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Litsk AnILS ee

ENTOMOLOGIC —
SOCIETY of
BRITISH COLUMBIA

‘Vol. 72 Issued December 31, 1975

ECONOMIC

DOWNING & MOILLIET — Preliminary trials with Citrazon—a selective
acaricide

PROVERBS & NEWTON — Codling moth centrol by sterile insect release:
importation of fruit & fruit containers as a source of reinfestation

: MADSEN & MORGAN — Mites and insects collected from vineyards in the
Okanagan & Similkameen Valleys, British Columbia

| Be RASKE & ROBINS — Wood borer control in spruce logs with p-dichlorobenzene
and plastic sheeting (Coleoptera: Cerambycidae)

GENERAL

RUBIN & BEIRNE — The European fruit lecanium, Lecanium tiliae (L.)
(Homoptera: Coccidae) in southwestern British Columbia

_ DYER, HALL & SAFRANYIK — Numbers of Dendroctonus rufipennis (Kirby)
& Thanasimus undulatus Say at pheromone-baited poisoned &
unpoisoned trees

| ‘ CANNINGS — Some Chironomidae (Diptera) new to British Columbia &

| CHO-KAI CHAN & FORBES — Life-cycle of a spiral gall aphid, Pemphigius
spirothecae (Homoptera: Aphididae) on poplar in British Columbia

TAXONOMIC

STAINER — The status of Conocephalus fasciatus vicinus (Morse, 1901)
(Orthoptera: Conocephalidae)

BOOK REVIEWS
NOTICE TO CONTRIBUTORS

JOURNAL

of the

ENTOMOLOGICAL
SOCIETY of
BRITISH COLUMBIA

Vol. 72 Issued December 31, 1975
ECONOMIC
DOWNING & MOILLIET — Preliminary trials with Citrazon—a selective
Sa UNGN CRG MME RC MNY fee fap cept tL oe nee hs os. hie a big Sy Sg Oe o te ees, lo ee ae ew we a
PROVERBS & NEWTON — Codling moth control by sterile insect release:
importation of fruit & fruit containers as a source of reinfestation ............ 6
MADSEN & MORGAN — Mites and insects collected from vineyards in the
Okanagan & Similkameen Valleys, British Columbia ..................-0000. 9
RASKE & ROBINS — Wood borer control in spruce logs with p-dichlorobenzene
and plastic sheeting (Coleoptera: Cerambycidae) ............... 000 cece eee 15
GENERAL
RUBIN & BEIRNE — The European fruit lecanium, Lecanium tiliae (L.)
(Homoptera: Coccidae) in southwestern British Columbia .................2.. 18

DYER, HALL & SAFRANYIK — Numbers of Dendroctonus rufipennis (Kirby)
& Thanasimus undulatus Say at pheromone-baited poisoned &

AM DUGIS ONC OMECES Beretta te hic elterg o seaco «© GER Rey Niece qe ee ook w aca foe ech oh ere rei See es 20
CANNINGS — Some Chironomidae (Diptera) new to British Columbia &

(CHUM, 4d eet Neen a pea eee a es ner eee MR Ser mr ee ae oe eee er 23
CHO-KAI CHAN & FORBES — Life-cycle of a spiral gall aphid, Pemphigius

spirothecae (Homoptera: Aphididae) on poplar in British Columbia ........... 26

TAXONOMIC

STAINER — The status of Conocephalus fasciatus vicinus (Morse, 1901)

‘Orthoptera: Conocephalidae)...< 6 c0cses 55 0 sew cee sd paw we 6 oe dese e wae 6 34
PAMPER TAMPERE VMIEAVY 9 etrcites Silas, Sis ie oia'se. 4:'o)sace wena aa este Wis eG Sue a e'w a Wieost! wie. Siew hah a oe aL 17, 35

J. ENTOMOL. Soc. Brit. CoLUMBIA 72 (1975), Dec. 31, 1975

Directors of the Entomological Society of
British Columbia for 1975 - 1976

President
J. R. CARROW

Pacific Forest Research Centre,
506 West Burnside Rd., Victoria

President-Elect

H. S. GERBER
B.C. Dept. of Agriculture, Cloverdale

Past President
T. FINLAYSON

Simon Fraser University,
Burnaby

Secretary-Treasurer

N. V. TONKS
2819 Graham St., Victoria

Honorary Auditor
D. G. FINLAYSON

Research Station, C.D.A., Vancouver

Editorial Committee
H. R. MacCARTHY

Vancouver
J. CORNER

Vernon

Directors

B. D. FRAZER (2nd) P. J. PROCTER (2nd)
J. MYERS (1st) B. AINSCOUGH (1st) R. CHORNEY (ist)

Regional Director of National Society
J. P. M. MACKAUER

Simon Fraser University, Burnaby

J. EnTomo.. Soc. Brit. CoLuMBIA 72 (1975), Dec. 31, 1975 3

PRELIMINARY TRIALS WITH CITRAZON—A SELECTIVE
ACARICIDE!

R. S. DOWNING AND T. K. MOILLIET

Research Station, Agriculture Canada,
Summerland, British Columbia

ABSTRACT

Citrazon (Ethyl O-benzoyl 3 chloro-2, 6-dmethoxy benzohydroximate)
was compared with two organotin acaricides Plictran and Vendex for mite
control on apples and pears. Citrazon controlled the phytophagous
European red mite, Panonychus ulmi (Koch) as effectively as Plictran and
Vendex and all were low in toxicity to the phytoseiid mites, Typhlodromus
occidentalis Nesbitt and T. columbiensis Chant. Unlike Plictran and Vendex,
Citrazon was much less toxic to another predatory mite, Zetzellia mali
Ewing, and to the pear rust mite, Epitrimerus pyri (Nal.).

An essential feature of a good acaricide for
integrated mite control is that it be selective.
The ideal one would be toxic to all harmful
mites but innocuous to the beneficial mites.
When used at the half-inch green bud stage,
mineral oil is very selective as it is toxic to the
eggs of the European red mite, Panonychus
ulmi (Koch), but has little toxicity to the pred-
aceous phytoseiid mites, eg. Typhlodromus
occidentalis Nesbitt, or to apple rust mite,
Vasates schlechtendali Nal., (Downing 1967).
Rust mites are an important alternate food
source for phytosiids as shown by Collyer
(1964) and help to make integrated mite con-
trol a success. Oil, however is not the ideal
acaricide as it can be phytotoxic and cannot
be used with safety during the summer season.
Propargite and the new organotin acaricides
such as Plictran and Vendex are selective as
they are toxic to European red mite, McDaniel
spider mite, Tetranychus mcdanieli McG., and
have low toxicity to the predaceous mite T.
occidentalis. However, these acaricides are
toxic to rust mites and to another predaceous
mite, Zetzellia mali Ewing, and may under
certain circumstances do more harm than good.
This is a report of laboratory and field trials
with a new acaricide, Citrazon.

MATERIALS AND METHODS
Citrazon was introduced by Nippon Soda
Co. Ltd., Tokyo, Japan, and is being developed
in Canada by Ciba-Geigy Canada Ltd. Its
chemical identity is Ethyl 0-benzoyl 3-chloro-
2, 6-dimethoxy benzohydroximate. Citrazon,
20% emulsifiable concentrate was compared
with the following selective acaricides in labora-
tory and orchard experiments:
Plictran 50% wettable powder,
tricyclohexyltin hydroxide. Vendex
50% wettable powder, Hexakis (beta,
beta-dimethylphenethyl)-distannoxane.

‘Contribution No. 415,
Canada, Summerland, B.C.

Research Station, Agriculture

Laboratory and Greenhouse Experiments

Toxicities of Citrazon and Plictran against
the native mite predators, T. occidentalis, T.
columbiensis Chant and Z. mali, were tested
in a Potter Spray Tower. Five predators were
placed on waxed black paper. This was floated
on cotton saturated with water in petri dishes.
Dishes were placed in the spray tower and ex-
posed to 2 ml of the spray mixture. Treatments
were replicated 6 times. Examination of the
predators with a steremicroscope was made
1, 2, and 3 days after treatment and the per-
centage mortalities obtained were corrected for
natural mortality in the check plots according
to the method of Abbot (1925).

European red mites were reared on potted
Red Delicious apple trees in a greenhouse and
these were sprayed on a turntable with a
Kellog-American compressed-air paint gun
sprayer that produced a fine even spray at a
pressure of 15 lb. per square inch (1 kg per sq.
cm). Volume of spray was not measured but
each tree was thoroughly sprayed to runoff.
Treatments were replicated 5 times. Estimates
of mite populations were made 3 and 10 days
after spraying by taking 5 leaves from each
tree and processing them by the method of
Henderson and McBurnie (1943) as modified
by Morgan et al. (1955).

Orchard Experiments

Sprays were applied with a high volume
hand gun sprayer operated at 425 p.s.1.
(30 kg per sq. cm) and the trees were sprayed
until dripping. Orchard trees were either Red
or Golden Delicious on semi-dwarf rootstalk
or Bartlett pears, all spaced 7% ft. by 15 ft.
(2.28 m x 4.57 m). Plot size was 3 trees with
3 replicates per treatment except for the ex-
periment summarized in Table 3 in which only
2 replicates were available. Estimates of mite
populations were made on 25-leaf samples
taken from the middle tree of each replicate and
processing these as above.

4 J. ENTOMOL. Soc. BRIT. COLUMBIA 72 (1975), Dec. 31, 1975

RESULTS AND DISCUSSION

Laboratory and Greenhouse Experiments

Table 1 shows that neither Citrazon 20%
E.C. 0.5 pt (284 ml) nor Plictran 50% W. P.
4 oz. per 100 gal. (25 gm per 100 1) were toxic
to the 2 predaceous phytoseiid mites, T.
occidentalis or T. columbiensis Chant: that
Citrazon was not toxic to the predaceous stig-
maeid mite, Z. mali, but Plictran was. T.
occidentalis is the most important of the 3

predators but under certain conditions the
other predators may be valuable in regulating
the densities of European red mite. T. colum-
biensis is much more cold-hardy than T. occi-
dentalis and sometimes after a very cold winter
is the only phytoseiid species that is present in
commercial orchards. Z. mali unlike T. occi-
dentalis, can usually survive when prey den-
sities are very low and is sometimes the only
predeaceous mite found in some commercial
orchards.

TABLE 1. Corrected percentage mortalities of mites in petri dishes 3 days after application of
acaricides in a Potter Spray Tower.

Acaricide per 100 gal.

Citrazon 20% E. C. 0.5 pt.
Plictran 50% W. P. 4 oz.

Citrazon and Plictran were equal in toxicity
to the European red mite and T. occidentalis
on apple trees in greenhouse trials. Both acari-
cides controlled the phytophagous mite and
allowed some survival of the predaceous mite
as shown in Table 2.

T. occidentalis T. columbiensis Z. mali
0 3 0
0 0 78

Orchard Experiments

Vendex and Citrazon showed a low toxicity
level when tested against JT. occidentalis on
Red Delicious apple trees. Even 1 pt per 100
gal. concentration (125 ml per 100 litre) of Cit-
razon, which is twice the concentration of

TABLE 2. Numbers of mites per 25 leaves after application of acaricides to potted apple trees
in a greenhouse.

Acaricide per 100 gal.

Citrazon 20% E. C. 0.5 pt
Plictran 50% W. P. 4 oz.
Check - no treatment

active ingredient of either Vendex or the lower
rate of Citrazon, allowed good survival of this
predatory species (Table 3). On Golden Delic-
ious trees, Citrazon gave quicker control of
European red mite and was almost non toxic to
Z. mali. Vendex, on the other hand, was slow
in controlling the red mite and quite toxic to
the predator Z. mali as summarized in Table 4.

European red mite T. occidentalis

3 days 10 days 3days 10 days
12 a 6 1
12 10 1 2
260 378 11 ue

Citrazon was compared with Plictran
against the pear rust mite, Epitrimerus pyri
(Nal.), and as shown in Table 5, Citrazon 20%
E.C. at 0.5 pt. or 1 pt. per 100 gal. (62.5 ml or
125 ml per 100 1) did not give adequate con-
trol whereas control with Plictran was excel-
lent.

TABLE 3. Numbers of T. occidentalis per 50 leaves before and after application of acaricides to
orchard apple trees with a high volume hand gun sprayer, 18 July 1973.

Acaricide per 100 gal.

Citrazon 20% E. C. 0.5 pt
Citrazon 20% E. C. 1.0 pt
Vendex 50% W. P. 4 oz.
Check - no treatment

Before spraying After spraying

July 17 July 24 Aug.1 Aug.9
90 21 23 24
119 11 9 8
99 15 17 10

112 29 28 17

J ENTOMOL. Soc. BRIT. COLUMBIA 72 (1975), DEc. 31, 1975 5

TABLE 4. Numbers of mites per 75 leaves before and after application of acaricides to orchard
apple trees with a high volume hand gun sprayer, 26 June 1973.

Before spraying After spraying

Acaricide per 100 gal.

June 26 July 3 July 11 Aug. 3 Sept. 5
European red mite
Citrazon 20% E. C. 1 pt 608 0 8 60 96
Vendex 50% W. P. 4 oz. 1208 121 192 7 33
Check - no treatment 688 348 3082 58 0
Zetzellia mali
Citrazon 20% E. C. 1 pt 10 8 37 113 204
Vendex 50% W. P. 4 oz. PA oS 0 3 OZ
Check - no treatment 29 44 251 174 62

This low toxicity to eriophyid mites such
as the pear rust mite or its close relative, the
apple rust mite, may be more of an advantage
for integrated control programs on apple be-
cause, as stated earlier, rust mites are an excel-
lent alternate food source for predaceous phy-
toseiid mites. Citrazon appears to have
qualities that will make it an excellent acaricide
for integrated mite control programs on apple.

red mite to reduce an outbreak to subeconomic
levels. The low toxicities of Citrazon to the
predaceous mites, T. occidentalis, T. colum-
biensis and Z. mali, and most likely to the
alternate food source for the predators, the
apple rust mite are very desirable properties
of a selective acaricide and would make Cit-
razon useful for integrated mite control pro-
grams on apple.

It seems to be sufficiently toxic to European

TABLE 5. Numbers of pear rust mite per 75 leaves after application of acaricides to Bartlett pears
with a high volume hand gun sprayer, 16 July 1974.

Before spraying After spraying

Acaricide per 100 gal.

July 15 July 22 July26 Aug.7 #Aug.13
Pear rust mite
Citrazon 20% E. C. 0.5 pt 30,500 245 296 417 940
Citrazon 20% E. C. 1.0 pt 19,400 80 170 543 846
Plictran 50% W. P. 4 oz. 30,200 4 8 6 28
Check - no treatment 18,900 3016 2016 1704 2108
References
Abbott, W. S. 1925. A method of computing the effectiveness of an insecticide. J. econ. Ent. 18:

265-267.

Collyer, E. 1964. The effect of an alternative food supply on the relationship between two Typh-
lodromus species and Panonychus ulmi (Koch) (Acarina). Entomologia exp. appl. 7:
120-124.

Downing, R. S. 1967. Petroleum oils in orchard mite control. J. Entomol. Soc. Brit. Columbia,
64: 10-13.

Henderson, C. F., and H. Y. McBurnie. 1943. Sampling technique for determining populations
of citrus red mite and its predators. U.S. Dep. Agric. Circ. 671.

Morgan. C. V. G., et al. 1955. Methods for estimating orchard mite populations, especially with
the mite brushing machine. Can. Ent. 87: 189-200.

CODLING MOTH!
IMPORTATION

J ENTOMOL. Soc. Brit. COLUMBIA 72 (1975), DEc. 31, 1975

CONTROL BY STERILE INSECT RELEASE:
OF FRUIT AND FRUIT CONTAINERS

AS A

SOURCE OF REINFESTATION 2

M. D. PROVERBS AND J. R. NEWTON

Research Station, Agriculture Canada
Summerland, British Columbia

ABSTRACT

A program of codling moth, Laspeyresia pomonella (L.), control by the
sterility principle is planned for the entire Similkameen Valley of British
Columbia. If the program is successful, reinfestation by moth fly-in is un-
likely because the Valley is fairly well isolated. Importation of host fruits
and fruit containers (bushel boxes) for roadside fruit stands could lead to
reinfestation unless the boxes are fumigated. Localized annual releases of
sterile moths around fruit stands may also be necessary. Orchard bins, used
by commercial packinghouses, are unlikely to be a serious source of

codling moth reinfestation.

INTRODUCTION

It has been shown that the codling moth,
Laspeyresia pomonella (L.), can be controlled
effectively by release of sterile moths, but the
method is about twice as expensive as
chemical control if releases have to be made
over the entire area every year (Proverbs 1974).
Results of small scale sterility programs, in
which treated orchards were exposed to fly-in
of inseminated female moths from nearby
orchards, have indicated that even under these
conditions of reinfestation it is usually un-
necessary to apply control measures in the
first year following termination of sterile moth
release, and that in the second year only one
spray is required instead of the normal 3-spray
program.

An area-wide sterile moth release program is
planned for the Similkameen Valley of British
Columbia. Because this Valley is semi-isolated,
moth fly-in would be virtually eliminated and
the effects of the program should persist for
some years. Pockets of reinfestation would
likely occur from time to time, but it should be
possible to eliminate these incipient infesta-
tions by localized release of sterile moths. Con-
sequently, in the long run, area-wide control
by the sterility procedure probably would be
cheaper than chemical sprays.

The validity of this premise was questioned
by fruit growers who pointed out that there
is some movement of fruit and fruit contain-
ers into the Similkameen Valley from distant
fruit-growing areas. Plywood bins used for
transporting fruit from orchards to packing-
houses are moved annually into the Similka-
meen to service a few growers who have their
fruit packed in the neighboring Okanagan
Valley. The imported empty bins may contain

‘Lepidoptera: Olethreutidae.
*Contribution No. 417, Research Station, Summerland

spun-up larvae and pupae of the codling moth.
A more likely source of reinfestation, however,
is from boxes of apples and pears that are
brought into the Similkameen for sale at road-
side fruit stands. Before the fruit is sold and
transferred to the purchaser’s container, some
mature larvae leave the fruit and spin-up in the
boxes where they complete development and
emerge as adult moths the following spring.
This report examines the importance of fruit
and fruit containers imported into the Simil-
kameen Valley as sources of codling moth re-
infestation after a _ theoretically successful
program of moth control by the sterility
method.

MATERIALS AND METHODS

The numbers of moths likely to emerge
from empty fruit containers in spring were
determined as follows. In early April, before
the start of adult moth emergence, 50 one-
bushel (ca. 36 dm*) wooden boxes, the stan-
dard fruit container used by fruit stand opera-
tors, were taken at random from each of 5 fruit
stands in the Similkameen Valley. The boxes
were placed in a mothproof room in which the
daily temperature fluctuation was between 21°
and 27° C and the light/dark regime was 18/6
hr. A screen-mouthed glass jar containing
ca. 100 laboratory-reared diapausing larvae
was placed in the room to determine whether
environmental conditions were satisfactory
for pupation and subsequent adult emergence.
A similar jar of larvae was held in the labora-
tory at ca 27° C and a light/dark regime of 18/6
hr. Because there was some doubt about the
health of the diapausing insects, 20 mature
nondiapausing larvae and 20 pupae were also
placed in the room in separate jars. Control
nondiapausing insects were kept in the labora-
tory. A 40-watt black light trap was installed
to capture the wild moths as they completed
development and emerged from the boxes.

J. ENTOMOL. Soc. BRIT. COLUMBIA 72 (1975), Dec. 31, 1975 ff

The efficiency of the trap was determined,

prior to the start of the adult emergence, by
introducing into the room a known number of
laboratory-reared moths that were marked
externally with Day Glo® fluorescent powder.
Later, when emergence of wild moths from the
boxes had commenced, the efficiency of the
trap was rechecked with moths marked in-
ternally with calco oil red. This marking
method was adopted to prevent pigment trans-
fer to wild moths which could lead to misidenti-
fication of the wild insects. The experiment
was discontinued 2 weeks after the last capture
of a wild moth.
_ The procedure for estimating the numbers
of moths likely to emerge from bins was essen-
tially the same as that used for boxes. The ex-
periment was conducted in a large storage room
in a packinghouse with 500 so-called standard
bins (0.8 m*) from the Summerland district.
The daily temperature fluctuation in the room
was between ca. 23° and 29° C and the light/
dark regime was 17/7 hr. Three screen-
mouthed glass jars, each with ca. 100 diapaus-
ing larvae, 3 with 10 nondiapausing larvae
and 10 pupae, and 2 with ca. 30 adult moths
each, were placed at different locations among
the bins. Four black light traps were installed,
and trapping efficiency estimated, prior to
emergence of wild adults, by release of a known
number of marked moths. The numbers of
traps were later increased to 8, and trapping
efficiency reassessed before emergence of wild
adults. The experiment was discontinued 3
weeks after the last capture of a wild moth.

Boxes

The environment in the room used for pro-
cessing the boxes was satisfactory for codling
moth development; adult emergence from the
caged nondiapausing insects was 95.0% in
the room vs. 92.5% in the laboratory. Emer-
gence from caged diapausing insects was much
less than that—an estimated 40% in the room
and laboratory. Microscopic examination of
dead and moribund larvae indicated that poor
emergence with caged diapausing insects was
due to a severe infection of granulosis virus.

Use of a single black light trap proved to be
an effective way of capturing adult moths in
the room. In the first trapping efficiency test
25 marked moths were released and they were
all captured within 3 days; in the second test
92 moths were released and 84 were captured.
Thus the average trapping efficiency was
93.16%.

Twelve wild (unmarked) moths were cap-
tured in the black light trap in the 7-week
period in which the 250 boxes were exposed to
long photophase at 21-27° C.

With respect to importation of fruit during
the growing season, only a very small number
of codling moths are likely to be introduced

with cherries, plums, apricots, and peaches. The
fruit itself would not be a carrier for only very
rarely are stone fruits infested with the codling
moth in British Columbia. If the boxes were
used the previous year for handling apples and
pears, virtually all the overwintered larvae
that were spun-up in the boxes would have
completed development and emerged as adult
moths before the commencement of stone fruit
imports, usually in early and mid July.

Moths could be introduced with imports of
late maturing cultivars of peach if the boxes
were used earlier in the year for very early
maturing cultivars of apples and pears. How-
ever, the numbers of moths introduced in this
way probably would be extremely small.

Very early maturing cultivars of apples,
which might be imported during the third week
of July, could be infested with small numbers
of late maturing first generation larvae. How-
ever, such imports would not contribute
measurably to reinfestation since the volume of
these imports is relatively small and by the
third week in July many or most of the first
generation larvae have already completed
development and left the fruit.

Large-volume imports of apples and partic-
ularly pears normally start in mid August
and it is these imports which could play an im-
portant role in reinfestation. Some of the fruit
would be infested with second generation larvae
and virtually all of those that develop to the
fifth instar would enter diapause and be po-
tentially capable of starting a new infestation
next spring.

We do not know what percentage of the
diapausing larvae spin up in the boxes, but
because the number of infested apples and
pears per box is very small, it seems reasonable
to assume that the vast majority of the larvae
would hibernate in or on the boxes for there
are many attractive spin-up sites in cracks and
corners of the boxes. Future investigations will
show whether larvae do leave the boxes and
whether artificial oviposition sites are needed
to trap these larvae.

Fruit stand operators normally use each
box several times yearly, sometimes for im-
ported fruit, other times for locally-grown fruit.
Despite this it is still possible to estimate the
approximate number of overwintered moths
that originate from imported fruit if we know
the total number of boxes used in the fruit
stand business, and the respective volumes of
imported and locally-grown fruit sold through
this outlet. We must also assume (and there is
no reason to believe otherwise) that the per
cent codling moth infestation is about the same
for imported and locally-grown fruit.

Fruit stand operators use a total of ca.
17,800 boxes in their business, and we estim-
ate that ca. 20% of apples and pears sold after
mid August (i.e, that period in which fruit is

8 J. ENTOMOL. Soc. BRIT. COLUMBIA 72 (1975) Dec. 31, 1975

infested with second generation larvae) are
imported. On the basis of the experiment con-
ducted with the Similkameen boxes, we would
expect 917 moths to emerge in spring from
17,800 boxes. About 20% of these, i.e. 183
moths, would be from imported fruit. Since
most of the moths would emerge in a 2-3-week
period, they could easily start new infestations
once sterile insect release is discontinued. The
most practical method of eliminating this
source of reinfestation is by fumigation of all
boxes with methyl bromide during winter.

Even though only small numbers of non-
diapausing insects are likely to come into the
Valley in boxes of stone fruits and early matur-
ing cultivars of apples and pears, they could
conceivably start new infestations. Traps, bait-
ed with the synthetic sex pheromone of the
codling moth, should be deployed around all
fruit stands to monitor adult moth populations.
Results of monitoring would indicate whether
yearly localized releases of sterile moths should
be made around all fruit stands, at least until
fruit stand owners can be convinced that they
should discontinue importing apples and pears,
and that only codling moth free boxes should
be used for importing stone fruits.

Bins

The environment in the room used for pro-
cessing the bins was satisfactory for comple-
tion of codling moth development; adult emer-
gence from caged nondiapausing insects was
93.3%. Emergence from caged diapausing
larvae was abnormally low, as in the previous
experiment with boxes.

Four black light traps were too few to give
maximum moth capture in the large room of
the packinghouse. When 49 marked adult
moths were released only 42 were captured.
Caged adult moths lived for several days indi-
cating that the relatively low trapping effi-
ciency (85.7%) was not due to poor adult sur-
vival. There was an appreciable increase in
trapping efficiency when the number of traps
was increased to 8; 94 of 100 released moths
were captured within 4 days.

Five wild (unmarked) moths were captured
in the light traps during the 7-week period in
which the 500 bins were exposed to long photo-
phase at 23-29° C. On the basis of 94% trapping
efficiency, emergence in spring would be 1.06
moths/100 bins.

About 2% of the Similkameen fruit growers
use imported bins to ship their fruit to Okana-
gan Valley packinghouses or to outside mar-
kets. Import of so-called half bins (0.4 m‘)
for the stone fruit harvest is unlikely to con-
tribute to codling reinfestation. Since Golden
Delicious is the only host fruit cultivar shipped
in half bins, their re-use for host fruits in any
one year is very restricted. Consequently,
there is only a very limited opportunity for
diapausing larvae to spin-up in the bins.

Furthermore, the few overwintered larvae
that might have been present would have
mostly completed development and emerged
as adult moths by the time the bins were im-
ported.

We estimate that ca. 530 standard and 290
half bins are shipped into the Similkameen
Valley every year for the apple and pear har-
vest. Empty bins are sometimes imported in
spring before adult emergence from overwin-
tered insects is complete. On the other hand,
imports are sometimes delayed so long that
some of the bins may have already been used

for early-maturing host fruits, and consequent-

ly may harbor small numbers of nondiapausing
larvae and pupae of the first generation. How-
ever, the probability of reinfestation is likely
to be very low since only ca 820 bins are in-
volved, and only ca. 8 moths should emerge in
spring from these bins on the basis of the
experiment conducted with Summerland bins.
The chances of reinfestation could be further
reduced by importing as many bins as possible
in early July, i.e., after adult emergence of over-
wintered insects, but about one week before
harvesting host fruits.

There soon may be another potential source
of codling moth reinfestation. The British
Columbia tree fruit industry is being reorgan-
ized and it is possible that some packinghouses
may eventually handle only certain species or
cultivars of fruit. This would entail a fairly
considerable movement of fruit and bins be-
tween fruit-growing areas, with consequent
increase in the chances of reinfesting the Simil-
kameen Valley. There is only a slight chance
that mature larvae will leave infested fruit after
it has been imported because the bins of fruit
are put into cold storage immediately on arrival
at the packinghouses. It is prior to transport,
when harvested fruit is often left in orchards
for 1 or more days, that mature larvae are
likely to leave the fruit and spin-up in the bins.
These will be almost entirely diapausing larvae.
Consequently, the contribution of imported
bins to reinfestation would be limited almost
exclusively to the following spring.

The number of moths that emerge from bins
in spring evidently is not large enough to create
a serious problem of reinfestation. About
11,500 bins are used in the packinghouse opera-
tions in the Similkameen Valley. On the basis
of our experiment at Summerland, this number
would contribute 122 adult moths to the over-
wintered codling moth population. However,
it seems unlikely that more than one-fourth of
the bins, i.e. 30 moths, would originate from
outside the Valley. If the standard bins were
held at Similkameen Valley packinghouses
until early July, it should be possible, by re-
leasing small numbers of sterile moths around
the packinghouses, to prevent emerging adults

J. ENTOMOL. Soc. BRIT. COLUMBIA 72 (1975), Dec. 31, 1975 9

from starting new infestations. The half bins
can be fumigated if they have to be distributed
to stone fruit growers before all the overwin-
tered insects have emerged. Of course, no bins
should be imported before early July in order
to avoid introducing overwintered insects.

In conclusion, it seems that the greatest
danger of codling moth reinfesting the Similka-
meen Valley after discontinuance of sterile

moth release would be through importation of
boxes of apples and pears for the fruit stand
trade. Incipient infestations could be sup-
pressed or avoided by fumigating the empty
boxes and by localized release of sterile moths.
At this time the numbers of imported bins are
so small that they are unlikely to contribute
to codling moth reinfestation.

Reference Cited
Proverbs, M.D. 1974. Codling moth control by the sterility principle: estimated cost and some
biological observations related to cost. Pages 81-88. In Proc. Panel on The Sterile-Insect
Technique and its Field Applications. I.A.E.A., Vienna, Austria.

MITES AND INSECTS COLLECTED FROM VINEYARDS IN THE
OKANAGAN AND SIMILKAMEEN VALLEYS,
BRITISH COLUMBIA!

B. J. MADSEN AND C. V. G. MORGAN
Research Station, Agriculture Canada,

Summerland, B.C.

ABSTRACT
Five species of mites and 122 species of insects were collected from
leaves, stickyboards and beating trays in 14 vineyards in 5 different areas
in southern British Columbia between May and October 1972. Two mite
species and 5 insect species are potential economic pests in British Columbia
but only one insect species, the Virginiacreeper leafhopper, Erythroneura

ziczac Walsh requires control measures.

INTRODUCTION
A survey of vineyards in the Okanagan and
Similkameen Valleys was made in 1972 to deter-
mine the species of insects and mites present,
their distribution, parasites and predators.

METHODS
Mites and insects were collected from yellow
stickyboards hung in vineyards, from grape
leaves examined under a binocular micro-
scope and from beating trays. In each vineyard
and for each variety the samples consisted of
10 leaves collected randomly, one beating tray

‘Contribution No. 403, Research Station, Summerland, B.C.

count from each of 10 vines and one yellow
stickyboard hung on the top trellis wire.
Samples were taken and stickyboards changed
at weekly intervals from 30 May to 6 October.
Insects were mounted or pinned and sent to
taxonomists at the Biosystematics Research
Institute, Ottawa, for identification. Mites
were identified by us along with R. S. Downing
and T. K. Moilliet of the Research Station,
Summerland, British Columbia. Varieties of
grapes sampled were Foch and Bath at West-
bank; Campbell Early, Patricia, Himrod, and
Sheridan at Kelowna; Riesling, Bath, Diamond
and S-10878 at Oliver; Foch at Cawston;
S-9549, Diamond and numerous experimental
varieties at Summerland.

10

J. ENTOMOL. Soc. Brit. COLUMBIA 72 (1975), DEc. 31, 1975

Insects and Mites Collected in Vineyards in the Okanagan and
Similkameen Valleys, British Columbia, 1972

Species Nos.
ACARINA
Phytoseiidae
Typhlodromus pyri Scheuten 370
Typhlodromus occidentalis (?) 36
Tetranychidae
Tetranychus urticae Koch 33
Panonychus ulmi (Koch) 250
Tydeidae
Tydeus sp 954
COLEOPTERA
Anobiidae
Coelostethus quadrulus LeC 1
Anthicidae
Anthicus sp. 2
Lappus nitidulus LeC. 4
Buprestidae
Anthaxia deleta LeC. 1
Anthaxia sp. a
Carabidae
Bembidion mutatum Gemm. 1
& Har.
Bradycellus californicus LeC. 1
Lebia guttula LeC. 1
Lebia viridis Say 1
Chrysomelidae
Crioceris duodecimpunctata(L.) 1
Epitrix tuberis Gentner 1
Phyllotreta sp. 2
Cleridae
Phyllobaenus humeralis Say or 9
near
Coccinellidae
*Cycloneda polita Csy. i
Hippodamia convergens Guerin 3
Hippodamia quinquesignata 6
(Kirby)
Microwesia sp. 4
Scymnus sp. 1
Stethorus sp. 3
Curculionidae
Brachyrhinus sulcatus (F.) 2,
Miccotrogus picirostris (F.) 1
Sitona cylindricollis Fahr. 1
Dermestidae
Cryptorhopalum sp. 1
Elateridae

Agriotes ferrugineipennis LeC. 1

Locality

Kelowna

Westbank, Summerland

Oliver, Cawston

Westbank, Summerland

Kelowna, Westbank,
Summerland

All areas

Kelowna

Oliver
Kelowna, Westbank

Kelowna

Kelowna, Summerland

Cawston

Cawston
Westbank
Kelowna

Oliver
Westbank
Cawston, Oliver

Cawston

Vernon

Kelowna, Westbank,
Cawston

Kelowna

Kelowna, Westbank,
Summerland
Cawston

Kelowna, Westbank,
Summerland

Kelowna, Westbank
Summerland
Westbank

Summerland

Cawston

*Collected at Vernon, B.C. at single sampling.

Collection
Method

leaves
leaves

leaves
leaves

leaves

board

tray
tray

board
board

board

board
tray
board

board
board
tray

board

board
board

board

board,
tray
board
board,
tray

tray
board
tray
board

board

Month
Collected

May-Sept.
May-Oct.

July-Oct.
June-Oct.

May-Oct.

July

July-Aug.
July

July
June

June
June
June
June
Sept.
June
June & Aug.
July
Sept.
June
June & Aug.
Aug.
June

July-Sept.

July & Oct.
July
Oct.
July

June

J. ENTOMOL. Soc. BRIT. COLUMBIA 72 (1975), Dec. 31, 1975

Cardiophorus edwardsi Horn

Dalopius sp.
Limonius infuscatus Mots.

Melanotus longulus oregonensis

LeC.

Lathridiidae
Lathridius minutus L.
Melandryidae
Anaspis atrata Champion
Anaspis sp.
Melyridae

Anthocomus sp. nr. nigrinus

Fall
Eurelymis atra LeC.
Listrus sp.

Malachius antennatus R. Hopp.

Mordellidae

Mordella atrata Melsheimer

Scarabidae

Onthophagus nuchicornis L.

Tenebrionidae

Coelocnemis californica Mann.

COLLEMBOLA
Entomobryidae
Entomobrya sp. perhaps
nivalis (L.)
Willowsia buskii Lubbock

DIPTERA
Ceratopogonidae
Atrichopogon sp.
Forcipomyia sp.
Chironomidae
Ablabesymia sp.
Chironomus sp.
Dicrotendipes sp.
Micropsectra sp.
Parachironomus sp.
Phaenopsectra sp.
Tanytarsus sp.
Dolichopodidae
Chrysotus sp.
Drosophilidae
Drosophila sp.
Ephydridae
Philygria opposita Lw.
Sciaridae
Bradysia sp.
Conioscinella sp.

Thaumatomyia glabra var.

EPHEMOROPTERA
Baetis sp. ?

HEMIPTERA
Anthocoridae
Orius tristicolor (White)

17

le a ee oe Nl el NS)

Summerland, Cawston
Oliver

Westbank

Westbank, Summerland

Cawston

Summerland
Kelowna, Summerland

Summerland
Kelowna
Summerland

Summerland

Kelowna, Westbank,
Summerland

Summerland

Westbank

Oliver

Kelowna

Oliver
Summerland

Summerland

Westbank

Westbank, Summerland
Westbank

Westbank

Summerland

Westbank

Kelowna
Summerland
Summerland
all areas

Summerland, Cawston
Kelowna, Oliver

Westbank

Kelowna, Westbank
Summerland

11
board June
board June
board April
board June-July

tray June
tray June
board June-July
board July
board June
board July
board June
board July
board Aug.
soil at base Nov.
of grapevine

tray Aug.
tray July
tray Oct.
tray June
tray Sept.
tray Sept.
tray Sept.
tray Sept.
tray Sept.
tray Sept.
tray June
board June
tray June
tray Sept.
tray June-Oct.
tray July & Sept.
tray June & Aug.
tray Aug.
board June-Sept.

tray

12 J. ENTOMOL. Soc. Brit. COLUMBIA 72 (1975), Dec. 31, 1975

Lygaeidae
Geocoris bullatus (Say) 1
Nysius ericae (Schilling) 13
Rhyparochromus chiragra 12

californicus Van D.
Sphragisticus nebulosus (Fallen) 1
Miridae

Campylomma verbasci (Meyer) 1
Ceratocapsus sp. 1
Deraeocoris (Camptobrochis) 19

brevis (Uhler)

Ilnacorella sulcata Kngt. 1
Lygus columbiensis (Kngt). 1
Lygus desertus (Kngt.) 1
Lygus elisus (Van D.) 1
Plagiognathus obscurus Uhler 2
Prepops sp. 1
Nabidae
Nabis ferus (Linn.) 67
Neididae
Neides muticus (Say) 2
HOMOPTERA
Aphididae
Esigella sp. 5
Cicadellidae
Aceratagallia sp. 1

Erythroneura ziczac Walsh 5000 +

Euscelidius schenki ( Kirsch.) 1

*Helochara communis Fitch 1)

Osbornellus borealis DeL. & Mohr 1

Stenocoelidia lineata (Baker) 1
Coccoidea

Lecanium sp. prob. coryli L. 200+

Phylloxeridae

Phylloxera vitifoliae (Fitch) 450+

Psyllidae
Psylla pyricola (Forster)
Psylla sinuata group 3

—

HYMENOPTERA
Bethylidae
Goniozus sp. 1
Braconidae
Bracon xanthonotus (Ashm.) 1
Lysiphlebus sp. 1
Orgilus sp i
Praon sp. 1
Torymidae
Torymus sp. 1
Encyrtidae
Aphycus maculipes How. 65
Aphycus sp. 1
Copidosoma bakeri How. 1
Microterys sp. i
Ooencyrtus nr. clisiocampae 1
(Ashm.)

Summerland
Summerland, Cawston

Oliver, Cawston
Summerland

Kelowna
Summerland
Kelowna, Oliver

Westbank, Oliver
Oliver

Oliver

Oliver
Summerland
Oliver

all areas

Westbank, Oliver

Summerland

Missing when specimens returned from Ottawa

all areas

Summerland
Vernon
Kelowna
Summerland

All areas

Kelowna, Westbank,
Oliver

Summerland
Oliver

Summerland

Summerland
Kelowna

Summerland
Summerland

Summerland

Oliver, Cawston
Kelowna

Oliver

Oliver

Kelowna

board July
board June-July
board July-Aug. |
board Aug.
board Aug.
board July
board July
tray

board Aug.
tray June
tray Aug.
board Aug.
tray July
tray Aug.
tray Aug.-Oct.
tray Aug.-Sept.
tray Sept.
tray, June-Oct.
leaves, board

tray June
board Sept.
tray Sept.
tray Aug.
leaves July-Sept.
board Aug.
tray Sept.
board Aug.
tray June
tray Sept.
tray Sept.
tray Oct.
tray Sept.
tray Oct.
board, tray Aug.
tray Sept.
tray Aug.
tray Aug.
tray Aug.

J. ENTOMOL. Soc. Brit. COLUMBIA 72 (1975), Dec. 31, 1975

13

Eulophidae
Euplectrus platyhypenae How. 2 Summerland tray Oct.
Eurytomidae
Harmolita sp. 1 Westbank board June
Figitidae
Anacharis nr. marginata (Prov.) 1 Oliver tray Aug.
Ichneumonidae
Campoletis argentifrons (Cress.) 2 Kelowna board June
Cremastus incompletus (Prov.) 2 Cawston board June
Diplazon laetatorius Fab. 1 Oliver board July
Itoplectis quadricingulata (Prov.) 1 Westbank tray Sept.
Mesoleiini 1 Oliver board Aug.
Stenomacrus sp. i Summerland board July
Symplecis sp 1 Cawston board June
Mymaridae
Anagrus epos Girault 475 all areas board July-Sept.
Polynema sp. il Oliver tray Aug.
Platygasteridae
Platygaster sp. 1 Kelowna tray June
Proctotrupidae
Proctotrupes rufigaster Prov. 1 Cawston board July
Pteromalidae
Habrocytus sp. 1 Summerland tray Sept.
Sphegigaster (poss. n. sp.) 1 Summerland tray Sept.
Scelionidae
Telenomus sp. A+ B 6 Oliver board July
Trissolcus sp. A 1 Kelowna tray June
Trissolcus sp. B il Westbank tray June
Trichogrammatidae
Oligosita sanguinea sanguinea 1 Oliver board July
Girault
LEPIDOPTERA
Lyonetidae
Bucculatrix sp. prob. 150 Summerland, Oliver tray Sept.
salutatoria Braun Cawston
Lyonetia sp. 1 Oliver tray July
NEUROPTERA
Chrysopidae
Chrysopa oculata Say 1 Summerland board July
Raphidiidae
Agulla adnixa (Hagen) 4 Summerland board June
PSOCOPTERA
Psocidae
Lachesilla pedicularia (L.) 12 Oliver, Cawston tray Sept.
Psocus sp. nr. oregonus 1 Summerland tray Sept.
THYSANOPTERA
Thripidae
Frankliniella tritici (Fitch). 9000+ all areas leaves, June -Oct.
board, tray
RESULTS phylloxera, Phylloxera vitifoliae (Fitch),

A total of 122 species of insects representing
54 families was collected by the three sampling
methods. Six of these species are grape pests
in the Okanagan-Similkameen area but only
one, the Virginiacreeper leafhopper, Erythro-
neura ziczac Walsh which causes leaf and fruit
injury requires control measures. The grape

although important in other grape growing
regions, has not yet been determined to be an
economic problem in British Columbia. Other
potential grape pests which at present cause
only minor injury and do not warrant control
measures in British Columbia are the flower
thrips Frankliniella tritici (Fitch); a lecanium

14 J. ENTOMOL. Soc. BRIT. COLUMBIA 72 (1975), DEc. 31, 1975

scale, Lecanium species probably coryli L.,
which may heavily infest grape vines (Phillips
1965); the black vine weevil, Brachyrhinus
salcatus (F.) and the clickbeetle Limonius
infascatus (Mots.).

Several predaceous insects were collected
by each sampling method and two parasites
were reared from their hosts, Anagrus epos
Girault the egg parasite of the Virginia-
creeper leafhopper and Aphycus maculipes
How., which parasitizes L. coryli. Six species
of Coccinellidae were collected including a
Stethorus sp. which is predaceous only on
mites. Other predaceous insects were three
Hemiptera, Neides muticus (Say), Nabis ferus
(Linn.), and Orius tristicolor (White) which feed
on thrips, aphids and other small insects; and
two Neuroptera. Agulla adnixa (Hagen) and
Chrysopa oculata Say, which attack a wide
range of insects.

Five species of mites were found on the leaf
samples. The twospotted spider mite, Tetrany-
chus urticae Koch, and the European red mite,
Panonychus ulmi (Koch), are _ potential

economic pests. The other three species are
mite predators with one, Typhlodromus pyri
Scheuten, having been recorded only once
previously in the Okanagan Valley (Downing
and Moilliet 1971). Another phytoseiid,
Amblyseius andersoni Chant found in 1974
on grape leaves from Westbank, had not been
recorded previously in the Okanagan Valley
(Chant and Hansell 1971).

The majority of insects collected from the
boards and beating trays were not directly
associated with grape plants, but originated
from cover crops or native plants near vine-
yards. For example, 150 specimens of Buccu-
latrix salutatoria Braun whose host is the sage-
brush, Artemisia tridentata Nutt., were taken
from beating trays.

Vineyard pests not encountered in the 1972
survey are several species of cutworms, a Pul-
vinaria scale and the grape erineum mite,
Eriophyes vitis (Pgst.). These pests have been
found in separate isolated vineyards in the
Okanagan-Similkameen area.

References
Chant, D. A., and R. I. C. Hansell. 1971. The genus Amblyseius (Acarina: Phytoseiidae) in
Canada and Alaska. Can. J. Zool. 49(5): 703-758.
Downing, R. S., and T. K. Moilliet. 1971. Occurrence of phytoseiid mites (Acarina; Phytoseiidae)
in apple orchards in central British Columbia. J. Entomol. Soc. Brit. Columbia 68: 33-35.
Phillips, J. H. H. 1965. Notes on species of Lecanium Burmeister (Homoptera: Coccoidea) in the
Niagara Penninsula, Ontario, with a description of a new species. Can. Entomol. 97:

231-238.

J. ENTOMOL. Soc. BRIT. COLUMBIA 72 (1975), Dec. 31, 1975 15

WOOD BORER CONTROL IN SPRUCE LOGS WITH P-DICHLORO-
BENZENE AND PLASTIC SHEETING
(COLEOPTERA: CERAMBYCIDAE)

A. G. RASKE'! AND J. K. ROBINS?

Canadian Forestry Service, Northen Forest Research Centre,
Edmonton, Alberta

ABSTRACT

Fumigation under plastic sheating of white spruce (Picea glauca
(Moench) Voss) logs with crystalline p-dichlorobenzene (PDB) for 26 days
killed more than 95% of cerambycid and other wood borer larvae under the
bark and in the wood, at the lowest dosage of 8g of chemical per cubic meter
of log plus air space volume. The long treatment-duration promoted the
discoloration of logs by stain fungi. When treatments were shortened to 2,
4 and 7 days, and the PDB was dissolved in trichloroethylene, the lowest
dosage at the shortest duration killed more than 80% of the wood borer

larvae.

INTRODUCTION

The lumber industry has expressed growing
concern over the degrading of lumber caused by
wood borers in decked logs. Some methods of
chemical preventative control have been pub-
lished (Becker and Abbot, 1961, Ross and
Downton, 1966, Gardiner 1970), and one study
(Buffam and Lucht 1968) reported that excess
heat in slash piles covered with clear poly-
ethylene sheeting killed bark beetles under the
bark. This paper reports the results of a pilot
study testing the effects of fumigation with
p-dichlorobenzene (moth balls), under plastic
sheeting, on mortality of wood borer larvae
under the bark.

METHODS

Two trials were made with borer-infested
logs of white spruce (Picea glauca (Moench)
Voss), in a clearing at the Kananaskis Forest
Experiment Station, Alberta. The logs were
covered with 6-mil clear plastic sheeting and
chemical placed under the covering. All logs
were collected about 80 km W of Olds. They
were less than one year old, and were severely
infested with mature wood borer larvae.

In the first test crystalline p-dichloro-
benzene (PDB) was used on fifteen log ‘‘decks’’,
three for each of the following: a control, plas-
tic covering only, plastic covering plus 8, 32,
and 128 g of PDB per cubic meter of wood plus
air space volume. The decks were about 0.6 m?
in volume and consisted of three to seven logs
each 67 cm long. Treatments began on 23 Sep-
tember 1968, and the decks remained covered
till 19 October 1968, when all the fumigant of
the largest dosage had evaoporated. Then all
live and dead larvae under the bark and in the
wood were removed, identified and counted.

' Present address: Canadian Forestry Service, Newfoundland
Forest Research Centre, St. Jon’s, Newfoundland.
* Present address: Box 514, Devon, Alberta.

About one-tenth of the larvae classified as dead
were kept at room temperatures for 24-48 hours
to verify this.

In the second test dissolved PDB was used
on one replicate each according to the experi-
mental design of Table 2. Treatment decks were
about 0.4° in volume and consisted of two 130
cm long white spruce logs, about 36 cm in dia-
meter. Treatment began on 22 May 1969 and
lasted 2, 4 or 7 days. The fumigant was dis-
solved in trichlorethylene’® at the rate of 1 gm
of PDB per 1 ml of solvent, distributed over the
deck, and the deck then covered with plastic
sheeting. The cover was removed after the pre-
scribed duration and all dead and live larvae
under the bark and in the wood were removed,
counted and identified about 10 days after
treatment.

RESULTS AND DISCUSSION

More than ninety percent of the wood
boring insects present in all logs were Tet-
ropium parvulum Casey (Cerambycidae). The
larvae of other species present in decreasing
numerical order were: Buprestidae— mainly
Melanophila supp.; Cerambycidae-Monocham-
us spp., Anoplodera spp., Acmeops sp., Tet-
ropium cinnamopterum (Kirby); and Meland-
ridae-Serropalpus sp. Differential mortality
among species apparently did not occur, and
the data were therefore combined.

Crystalline PDB The fumigant in crystalline
form gave effective control of wood borer lar-
vae under the bark at all dosages (Table 1).
The total mortality given in Table 1 includes a
percentage of natural mortality, which is
assumed to approximate the percentage mor-
tality (20%) in the controls. Natural mortality
was recognized by a brown discoloration of the

‘Supplied by Dow Chemical of Canada Ltd. of Calgary un-

der the trade name of ‘‘Neu-tri’’.

16 J. ENTOMOL. Soc. BRIT. COLUMBIA 72 (1975), Dec. 31, 1975

TABLE 1—Mortality of wood borer larvae in three replications of white spruce log ‘‘decks’’ fumi-
gated with granular crystalline p-dichlorobenzene for 26 days, under plastic sheeting.

Treatment

Control

Plastic sheeting only
8 g/m?’ of PDB

32 g/m?’ of PDB

128 g/m’ of PDB

larvae, or by fungal growth on the dead larvae.
Heat built up under the plastic apparently did
not contribute appreciably to larval mortality
in this experiment since mortality was also
low (26%) in the plastic-only treatment.
Crystalline PDB also penetrated into the logs
or into the plugged larval tunnels, killing larvae
in the pupal cells 10 cm in the log.

In all PDB treatments, live larvae were very
sluggish compared to those in control and plas-
tic-only logs. Bark beetle larval mortality was
estimated at 60%, 90%, and 98% at dosages
of 8, 32, and 128 g per m’ of log deck, respec-
tively.

Of special interest is that parasitic larvae,
mainly Braconidae, exhibited a much greater
tolerance to PDB than did the wood borer
larvae. Mortality of parasites in cocoons could
not be judged, but mortality of free parasitic
larvae was negligible, except at the heaviest
dosage, when it reached about 75%.

The high humidity and temperatures main-

tained under the plastic sheeting promoted:

severe discoloration of logs by blue-stain fungi,
which would degrade lumber from logs treated
in this way as much as would the ‘‘worm-

No. live No. dead
wood borer wood borer Percent
larvae larvae mortality

Totals of three replications

265 66 199
378 138 26.8
16 379 96.0
7 305 97.8
2 398 99.5

holes’. It is therefore important that decks be
covered with plastic for a short fumigation
period only.

Dissolved PDB The dissolved fumigant
treatments increased mortality of wood borer
larvae compared to the control, at all durations
(Table 2), but the total mortality was less than
it was with crystalline PDB. Many live larvae
were found where logs contacted the soil, indi-
cating that the fumigant apparently did not
penetrate these areas within seven days. Treat-
ed logs showed no perceptible increase in wood
stain from fungi during treatment.

A treatment with only the solvent, which
is slightly toxic, was not done. The addition of
the solvent did not increase mortality appreci-
ably, because the total mortality of chemical
plus solvent was lower than that with crystal-
line PDB.

Since both the plastic and PDB are
inexpensive compared to the value and volume
of the logs treated, utilizing this chemicaal in
liquid form may be feasible if applied in June or
July when wood borer larvae are in the early
stages of development, and have not yet bored
into the wood. Estimated cost for insecticide
and 6-mil plastic sheeting, based on a deck 5 m

TABLE 2 — Mortality of wood borer larvae in white spruce log ‘‘decks’’ fumigated with dissolved

p-dichlorobenzene under plastic sheeting.

2 days 4 days 7 days
No. No. % No. No. % No. No. %

Treatment live dead dead live dead dead live dead dead
Control 42 12 2252
Plastic

sheeting 11 10 47.7
only

8 g/m? 8 62 88.6 15* 48 76.2 | 47 87.2
32 g/m? 0 22, 100 5 35 85:3" “tar 24 68.6
128 g/m? 1 28 96.7 0 Pag 100 9* 25 67.6

*Live larvae in portion of log in contact with soil.

J. ENTOMOL. Soc. BRIT. COLUMBIA 72 (1975), Dec. 31, 1975 17

wide, and 60 m long is 10° to 15° per 2.36 m°
(=M bd. ft.) (1969 prices). If care is taken
to prevent snagging and tearing, the sheeting
can be reused, thus greatly reducing the cost
of treatment.

A present PDB is one of the _ safest
chemicals in use agains insects. Its ability to
penetrate into wood and kill boring insects in

a relatively short time may have wide applica-
tion in the lumber industry.
Acknowledgements

We thank B. M. Dahl for his help in setting
up the experiment and in collecting data, Dow
Chemical of Canada who supplied the p-
dichlorobenzene and solvent, and Dr. H.
Cerezke for critically reading the manuscript.

Resume

La fumigation des billes d’Epinette blanche (Picea glauca (Moench)
Voss) au p-dichlorobenzéne (PDB) cristallin pendant 26 jours a tue plus de
95% des larves de perce-bois sous |’ecorce des billes et dans le bois ’ 4 la dose
minimale de 8 g de produit chimique par metre cube de bille plus volume
spatial d’air.LLalongue duree du traitement a cause la decoloration des billes
par des Champignons de decoloration. Les periodes de traitement ont éte
reduites a 2, 4 et 7 jours et le PDB a eté dissous dans du trichloroethyléne.
La dose minimale a la plus courte duree a tue plus de 80% des larves de

perce-bois.

References
Becker, W. B., and H. G. Abbott. 1961. Prevention of insect damage to decked pine sawlogs in
Massachusetts with BHC emulsion sprays. J. Forestry 59: 366-369.
Buffam, P. E., and D. D. Lucht. 1968. Use of polyethylene sheeting for control of Ips spp. in log-

ging debris. J. econ. Ent. 61: 1465-1466.

Gardiner, L. M. 1970. New northern Ontario spruce beetle compels May start on log spraying.

Canadian Forest Industries, July 1970.

Ross, D. A. and J. S. Downton. 1966. Protecting logs from long-horned borers with lindane

emulsion. For. Chron. 42: 377-379.

BOOK REVIEW
Borden, J. H. and Herrin, B.D. 1972. Insects
in the Classroom. B.C. Teachers’ Federation,
Vancouver. 147 pp. $3.50

Years ago this society discussed the idea
of producing a school book on insects and even
struck committees to investigate the problems.
It is ironic that when a member independently
authored such a book, the society as a whole
appeared to be unaware of it. Another society
has taken note, and with approval (see Bull.
Ent. Soc. America 20(3) p. 218. 1974).

The book is a three-way collaboration. Pro-
fessor Borden of Simon Fraser University
supplied the basic knowledge; his co-author, a
teacher in Vancouver, supplied the presenta-
tion; and the artist, Poul Neilson, supplied
much of the interest. The Teachers’ Federation
and some named individuals also contributed.
Physically, the book is 8% x 7 inches, with
Paper covers, perforated pages and plastic
spine, so that it lies perfectly flat when open.
Some of the typography is open to criticism.
Chapter and sub-heads in lower case letters
with no capitals are followed by sub-sub-heads
in large, block capitals. Both gimmicks are out
of place, but perhaps the authors are not re-
sponsible. The line drawings range from ade-
quate to excellent.

There are two parts. The first covers the
necessary systematics, including four non-

insectan Arthropod Classes and 22 Orders of
insects. Each taxon is given one page on which
is included: a line drawing of a typical repre-
sentative; the derivation of its ordinal name and
the common names; and characteristics, habits
and importance in a paragraph apiece. Within
the constraints of available space, these are
very well done. Short chapters on metamor-
phosis, populations, and good and bad insects
complete Part 1.

Part II is more ambitious, with longish
chapters on collecting, rearing, experimenting
and getting information, plus a bonus of three
pages on possible and probable disasters.
Little is missed that could possibly be included,
except a note on avoiding otherwise inevitable
damage by dermestids in collections. Experi-
ments with choice chambers, temperature
preferences, tasting and feeding in flies, soil
insects, flight mills, nutrition, etc. are described
with a maximum of ingenuity and a minimum
of expense. Good directions are given for rear-
ing Drosophilia, flour moths, blowflies, meal-
worms and locusts.

The last chapter (9) is a useful annotated
list of biological supply houses, books, films
etc., Provincial Entomologists and State Ex-
tension Directors. A detailed 8-page index
completes this excellent, and for its avowed
purpose, highly recommended book.

H. R. MacCarthy

18

J ENTOMOL. Soc. BRIT. COLUMBIA 72 (1975), Dec. 31, 1975

THE EUROPEAN FRUIT LECANIUM, LECANIUM TITLIAE (L.)
(HOMOPTERA: COCCIDAE), INSOUTHWESTERN
BRITISH COLUMBIA

by

AMOS Y. RUBIN* AND B. P. BEIRNE

Pestology Centre, Department of Biological Sciences,
Simon Fraser University, Burnaby, B.C. V5A 1S6

ABSTRACT

Lecanium tiliae normally has one annual generation in southwestern
British Columbia. There was a partial second in a year following a mild
winter. The heaviest infestations were on horse chestnut, Japanese plum,
hawthorn, and maple, in that order. Hawthorn was damaged. The propor-
tion of males tended to be higher in high than in low populations, and to
decrease with increasing altitude. Severe winter cold caused marked popu-
lation decreases and cold weather in June noticeable decreases. Natural

enemies found in 1969-72 are listed.

The European fruit lecanium, Lecanium
tiliae (L.) (formerly referred to as L. coryli
(L.)), was introduced into southwestern
British Columbia about 1903, probably from
Holland (Lyne 1927). There were severe in-
festations in the Vancouver area in 1925-30,
1937-46, and 1964-72. The following observa-
tions on the biology and ecology of this scale
were made in 1969-72, during a study of its
natural enemies reported elsewhere (Rubin and
Beirne 1975). They supplement observations
by Glendenning (1925, 1931, 1933, 1934) and
by Graham and Prebble (1953) on earlier in-
festations, and are based on collections of
infested leaves or twigs.

Life-Cycle

There is normally one generation per year
in British Columbia. The crawlers hatch from
the eggs in May and feed on the leaves until
late August when they become second instar
larvae and migrate to the twigs and small
branches, where they feed until September or
October. Here they overwinter. No evidence
could be found that they overwinter or fallen
leaves, which sometimes happens in Europe
(Krassilstchik 1915). The males appear early
in April, after a pupation period of about a
month. Egg-laying starts in May.

Host-Preferences

The lecanium scale feeds on various deci-
duous trees and shrubs. Regular surveys were
made of the number of scales on leaves and on
50 cm of twig or branch, on six species of trees,
selected as being common host-plants in the
Vancouver area. A total of 241 random samples,
containing 50,022 scales, were taken from the

trees at different times. In addition, six
selected samples, containing a total of 6,401
scales, were taken from heavy infestations on
unidentified maple.

The average numbers of scales in the ran-
dom samples of 50 cm of twig or branch were:
horse chestnut 319 (17 samples); Japanese
plum 81 (41); hawthorn 67 (48); maple 60 (29);
black cherry 37 (25); and red alder 33 (15).
Average on apple was 52 (3) and on sweet
cherry 7 (2). The average for the selected
samples from the heavy infestations on maple
was 1,089 (6). The single most heavy infesta-
tion had 3,072 scales per 50 cm of maple
branch.

Pest Significance

The scale becomes a pest by sucking juices
from leaves and twigs of the trees and by pro-
ducing honeydew that is a nuisance when it
drops on cars and clothing and on which grows
a black fungus or “sooty mould’, Fumago
spp., that inhibits photosynthesis.

Its pest importance is not always related
directly to its population density. Trees such as
horse chestnut that have large crowns suffer
less damage than do trees with small crowns
such as Japanese plum and hawthorn, even
when horse chestnut has a more dense popula-
tion than the others. Young trees are damaged
most because they have the highest proportion
of the young twigs on which the scales tend to
concentrate. Hawthorn appeared to be par-
ticularly affected by scale attack in 1969-72:
many infested twigs and small branches dried
up and died; and infested leaves were usually
smaller and sometimes thicker than non-infest-
ed ones. Tree damage in the 1925-30 infestation
was sufficiently severe to warrant extensive

*Present address: Nature Reserves Authority, 16 Hanatziv Street, Tel-Aviv, Israel.

J ENTOMOL. Soc. BRIT. COLUMBIA 72 (1975), Dec. 31, 1975 19

spraying annually, which, incidentally, may
have intensified that infestation by killing
parasites of the scale.

Scales, especially males, were sometimes
found trapped and drowned in the honeydew
and in the secretions from the buds of some
trees, notably of red alder.

Sex Ratio

In Europe males are usually rare, repro-
duction commonly is parthenogenetic, the sex
ratio can be much influenced by climate, and
the proportion of males decreases with increas-
ing altitude (Thiem 1932). Glendenning (1925)
found that males were much more numerous
than females by about 3:1. In the present
study, 19,359 scales were examined to de-
termine their sex: 19.7% were males, or about
5.

There was wide variation in the proportion
of males in scale populations on different host
plants. It was above the average on Japanese
plum (30%), horse chestnut and sweet cherry
(27% each), but lower than the average on haw-
thorn (16%) and maple (14%, but 18% on the
heavily infested trees), and much lower on red
alder (8%) and black cherry (7%). In general,
the proportion of males tended to be higher on
hosts with high scale densities than on hosts
with low ones.

Surveys of infestations at altitudes of up
to 500 m indicated that, as in Europe, there is
a decrease of 19% in the proportion of males
with each increase of 100 m of altitude (signi-
ficant at 5%). There was a decrease of 8% in
the proportion of males with each increase
of 10°C (significant at 5%).

Influences of Weather

At times in 1969-70 scale populations, as
indicated by numbers per 50 cm of branch,
decreased markedly. Some of these decreases
coincided with the occurrence of weather ex-
tremes, as follows:

There were decreases on three species of
host plants between November 26 and Decem-

ber 31, 1971: from 307 to 122, 301 to 83, and:

396 to 82 scales per 50 cm. December 1971
was very cold, with average temperatures of
-0.6° and 0.6°C at Burnaby Mountain and
Vancouver Airport, respectively, as compared

with the long-term winter monthly averages
at those locations of 0.5°C and 1.7°C. Decreases
on various host plants in the fall of 1970, from
31 to 7 between September 9 and 24, 62 to 12
between September 24 and October 8, 2,346 to
114 between November 15 and 21, coincided
with a cold autumn and the beginning of a
severe winter. There was also a decrease from
121 to 61 between February 1 and 16 and, ona
similar plant, from 226 to 59 between March 3
and 12, both in the severe winter of 1970-71.

In 1971 a cold June was followed by a
warmer than average July and August. Some
scale populations decreased on various host
plants from 133 to 35 between June 24 and
July 15, 39 to 3 between June 30 and July 31,
and 102 to 39 between June 30 and August 31.

The scale became active earlier than usual
in the spring of 1970, following a very mild
winter. This extension of its active period pre-
sumably was why there was an abnormal
partial second generation in the fall of 1970.

It appears from these observations that
temperature can be important in regulating
scale populations.

Natural Enemies

The most important natural enemies in
1969-72 were the hymenopterous parasites
Blastothrix longipennis (How.), Metaphycus
kincaidi Timb., and Coccophagus lycimnia
(Walk.). They are discussed elsewhere (Rubin
and Beirne 1975).

The following is a list of the predators en-
countered:

Arachnida. Araneae (det. D. J. Buckle):
Araneus diadematus Cl., Araneus sp., Por-
homma sp., Coriarachne brunneipes Banks;
Acarina (det. R. S. Downing): Typhlodromus
pyri Scheut., Amblyseius masseeit Nesb., A.
morgani Chant, and various Tydeiade and
saprophytic mites.

Insecta. Dermaptera (det. R. J. Lamb):
Forfiucula auricularia L.; Hemiptera (det. G. J.
Fields): Anthocoris antevolens White; Cole-
optera (det. J. .V. Richerson): Chilocorus fra-
ternus LeC.; Neuroptera (det. K. H. Martin):
Hemerobius_ pacificus Banks, Hemerobius
sp. prob. humulinus L., Chrysopa_harrisii
Fitch.?, C. carnea Steph.?.

References
Glendenning, R. 1925. The lecanium scale outbreak in Vancouver, B.C. Proc. Ent. Soc. Br.

Columb. 22:21-26.

Glendenning, R. 1931. The lecanium scale, an insect affecting fruit and shade trees on the Pacific
coast. Canada Dept. Agric. Circ. No. 77. 4 pp.
Glendenning, R. 1933. A successful parasite introduction into British Columbia. Can. Ent. 65:

169-171.

Glendenning, R. 1934. On the control of Eulecanium coryli (L.) in British Columbia by the para-
site Blastothrix sericea (Dalm.). Proc. Fifth pac. Sci. Cong., Canada 1933, 5: 3543-3545.

Graham, K. and M. L. Prebble. 1953. Studies on the lecanium scale, Eulecanium coryli (L.), and its
parasite Blastothrix sericea (Dalm.), in British Columbia. Can. Ent. 8% 153-181.

20 J. ENTOMOL. Soc. Brit. COLUMBIA 72 (1975), Dec. 31, 1975

Krassilstchik, I. M. 1915. (Report on the work of the Bio-Entomological Station (of Bessarabia)
during 1914. Govt. of Bessarabia, Kishinev, 1915, 49 pp. In Russian) Abstract in Rev.

Appl. Ent. 3: 395-398.

Lyne, W. H. 1927. Lecanium coryli. Spec. Publ. Calif. Dept. Agric. No. 73, p. 35.
Rubin, A. and B. P. Beirne. 1975. Natural enemies of the European fruit lecanium, Lecanium tiliae
(L.) (Homoptera: Coccidae), in British Columbia. Can. Ent. 107: 337-342.
Thiem, H. 1932. Pleisozontie als Arterhaltungsprinzip. Jenaische Z. naturw. 67: 488-492.

NUMBERS OF DENDROCTONUS RUFIPENNIS (KIRBY) AND
THANASIMUS UNDATULUS SAY AT PHEROMONE-BAITED
POISONED AND UNPOISONED TREES

b
E. D. A. DYER, P. M. H

y
ALL AND L. SAFRANYIK

Department of the Environment
Canadian Forestry Service
Pacific Forest Research Centre
Victoria, B.C.

ABSTRACT

Four times as many spruce beetles, Dendroctonus rufipennis (Kirby),
were killed at spruce trees (Picea engelmannii Parry, Picea glauca (Moench)
Voss) baited with frontalin and sprayed with insecticide than at trees baited
but unsprayed. Many clerid predators, Thanasimus undatulus Say, were also
killed at the baited and sprayed trees. Their numbers were correlated with
those of killed spruce beetles. Other correlations show that sprayed and
unsprayed trees were exposed to the same attacking spruce beetle popula-
tion and that predation on the spruce beetles was occurring.

INTRODUCTION

A synthetic pheromone, frontalin (Kinzer
et al., 1969) causes aggregation in both sexes
of spruce beetle (Dendroctonus rufipennis
(Kirby)) and a clerid predator (Thanasimus
undatulus Say), when released from polyethy-
lene capsules on living spruce trees (Picea
glauca (Moench) Voss, P. engelmannii Parry)
(Dyer, 1973). Insecticide sprayed onto the lower
3.0 m (10 ft) of tree boles kills all arriving in-
sects, and thus prevents the establishment of
galleries by spruce beetles and predation by
T. undatulus (Dyer, 1973). Without insecticide,
some arriving spruce beetles enter the bark of
baited trees and attempt to reproduce, even
though resistance by the tree may prevent
subsequent egg hatching or development of
brood. The predators, attracted to baited trees,
arrive at about the same time as the first
beetles, which gives them an opportunity for
predation, which would probably not occur
during natural attacks when some _ spruce
beetles would have entered the bark before
producing pheromone (Dyer, 1973). The follow-
ing experiments carried out in 1973 and 1974
were designed to determine any differences in
numbers of spruce beetles and predators at
baited trees sprayed with insecticide, and the
numbers of spruce beetles in baited, unsprayed
trees.

METHODS

Near Prince George, B.C., 133 spruce trees,
about 20.1 m (66 ft) apart in a line around a
stand perimeter in the Naver forest, were
baited with 1.0 ml of 1 part frontalin and 2
parts alpha-pinene, in May 1973. Two polyethy-
lene capsules, containing the frontalin-pinene
mixture, were placed on each tree on opposite
sides at breast height. Every tenth tree was
sprayed to drip with insecticide (lindane
0.5% in water) on the basal 3.0 m and was fitted
with a wire-screen basket at the base (Dyer,
1973).

Collections from the baskets were made
about twice a week, from June 14 to the end of
August. In August, bark samples of 20.3 x 25.4
cm (8 x 10 inches) were removed from 25 trees
randomly chosen out of the 91 attacked trees.
A minimum of four samples was taken from
each tree, one from each of the north and south
aspects at breast height and at the base. If the
attack height was greater than 1.8 m (6 ft) a
further two samples were taken from the north
and south aspects midway between breast
height and attack height. The number of
attacks, i.e. entrance holes, was counted for
each sample.

In 1974, ten pairs of spruce trees were
selected at about 403.3 m (1320 ft) intervals,
in the Naver forest near the 1973 experiment.

J. ENTOMOL. Soc. BRIT. COLUMBIA 72 (1975), DEc. 31, 1975 21

Each pair had approximately the same dbh
(+5 cm) and the trees were spaced about 20 m
apart. Both trees of a pair were baited with
frontalin and alpha-pinene, as was done in the
1973 experiment and one tree from each pair
was sprayed with lindane and fitted with a
screen basket as described. Screen baskets
were also placed on seven of the ten unsprayed
trees. Collections were made from all screen
baskets about twice per week, from June 4 to
August 28. Fragments of spruce beetles, such
as pairs of elytra, were collected from baskets
on unsprayed trees as evidence of arthropod
predation.

At the end of the spruce beetle flight period
in August, from five to 14 randomly distributed
(20.3 x 25.4 cm) bark samples were removed
from the unsprayed trees to obtain an estimate
of the mean attack density. The estimated num-
ber of beetles was calculated by using the total
attacked surface area of each tree, attack

density, and the male to female ratio found in
the sprayed-tree collections. Analysis of these
data included three correlations: (1) between
the number of spruce beetles and the number of
Thanasimus caught on each date at the sprayed
trees; (2) between the number of Thanasimus
caught at each sprayed tree and the number
of predator-killed spruce beetles at the corres-
ponding unsprayed tree, and (3) between the
number of spruce beetles caught at each spray-
ed tree and the estimated numbers under the
bark of each corresponding unsprayed tree.

RESULTS AND DISCUSSION

In 1973, the average numbers of spruce
beetles and T. undatulus killed per sprayed
tree were 130.5 and 73.7, respectively. The aver-
age number of spruce beetles in the unsprayed
trees was 43.5 (Table 1), or one-third the num-
ber killed at sprayed trees. At the sprayed
trees, the ratio of JT. undatulus to spruce
beetles was 1 to 1.8.

TABLE 1. Numbers of D. rufipennis and T. undatulus caught at insecticide-sprayed and unsprayed
trees baited with frontalin in 1973.

Dendroctonus caught at
sprayed trees

Thanasimus caught at
sprayed trees

Estimated no. of
Dendroctonus in attacked
unsprayed trees

1/ 95% confidence belt

In 1974, the average numbers of spruce
beetles and T. undatulus killed per sprayed
tree were 1703.8 and 418.0, respectively. The
average number of spruce beetles in the un-
sprayed trees was 395.7 (Table 2); about one
fourth the numbers at sprayed trees. One T.
undatulus was killed for each four spruce
beetles on the sprayed trees, nearly half the
ratio found previously. Fragments of spruce
beetles were found in the screens on the un-
sprayed trees (Table 2), indicating that preda-
tion was occurring.

In the 1974 study, the follwing three pairs
of variables were linearly related with signifi-
cant (P <.01) correlation coefficients: (1) the
number of D. rufipennis caught at sprayed
trees and the number in unsprayed trees
(r=0Q.77); (2) the number of D. rufipennis and
T. undatulus caught at sprayed trees (r=0.87);
and (3) the number of 7. undatulus and the
number of predator-killed D. rufipennis at
paired trees (r=0.88).

Since the numbers of D. rufipennis at spray-

No. of trees Mean no./ Std. error %33/
sampled tree of mean

130.5 44.68 40.1+0.2

ed and unsprayed trees were significantly
correlated, each of a pair of trees was exposed
to the same or similar attacking populations.
Therefore, some factor other than available
population determined the difference in num-
bers at the sprayed and unsprayed trees. Since,
at sprayed trees, the number of J. undatulus
caught was correlated with the number of D.
rufipennis caught and, at unsprayed trees, with
the number of D. rufipennis destroyed, preda-
tion was one factor that reduced the number
of beetles entering unsprayed trees. However, a
precise count of the number of D. rufipennis
killed by T. undatulus is difficult to obtain
because some evidence of predation is lost in the
bark crevices and spider webs on the tree boles;
moreover, other insect predators may have
killed attacking beetles. Table 2 shows that each
T. undatulus would have had to remove about
three spruce beetles to account for the reduced
number in the unsprayed trees compared to
those caught at the sprayed trees.

In 1974, the estimated ratio of predator to

22 ~ J. Entromot. Soc. Brit. COLUMBIA 72 (1975) Dec. 31, 1975

TABLE 2. Numbers of D. rufipennis and T. undatulus caught at insecticide-sprayed and unsprayed
trees baited with frontalin in 1974.

Dendroctonus caught at
sprayed trees

Thanasimus caught at
sprayed trees

Estimated no. of
Dendroctonus in attacked
unsprayed trees

Predator-killed
Dendroctonus at
unsprayed trees

1/ 44.4% 3 + 0.16% (95% confidence belt)

No. of trees
sampled

Std. error
of mean

Mean no./
tree
1703.8'/ 274.21

2/ Based on parts of D. rufipennis, such as pairs of elytra, in screen baskets at tree bases.

prey decreased from that of 1973, which should
have resulted in a higher proportion of the
arriving spruce beetles entering the trees,
if predation were the only factor influencing
attack density. However, the proportion was
less in 1974 (0.23: 1) than in 1973 (0.33:1),
indicating that some mechanism other than
predation influenced the number of beetles
entering the unsprayed trees. Nijholt (1973),
studying another’ scolytid, Trypodendron
lineatum (Oliv.), showed that the presence of
males masked the secondary attraction of fe-
males. Hedlin' found that when using an in-
secticide on logs, the natural secondary
attraction of Trypodendron females in the logs
continued to attract other beetles longer and in

‘A. F. Hedlin personal comminciation.

greater numbers to treated rather than to un-
treated logs, presumably because the males
were killed before they could join the females.

An _anti-aggregative pheromone MCH
(3-methyl-2-cyclohexen-l-one) is produced by
spruce beetles after entering the host tree
(Kline et al., 1973; Rudinsky et al., 1973).
MCH repelled D. rufipennis from attractive
host logs and felled trees when released nearby.
Since it is probable that MCH was produced by
the beetles after both sexes had entered the un-
sprayed trees, later arriving beetles in similar
numbers would have been repelled from entering
the unsprayed trees while the sprayed trees
would have continued to be attractive through-
out the flight period.

Résume

Les auteurs rapportent que 4 fois plus de Dendroctones de l’Epinette,
Dendroctonus rufipennis (Kirby), furent tues sur des Epinettes (Picea en-
gelmanii Parry, Picea glauca (Moench) Voss) appatees avec de la frontaline
et arrosees avec un insecticide, que sur des arbes appates mais non arrosés.
Plusieurs predateurs Clérides appartenant a Thanasimus undatulus Say,
ont également eté tues sur des arbres appates et arroses. leurs nombres ont
ete misencorrélation avec ceux des Dendroctones. D’autres corrélations
ont demontré que les arbres arroseés et non arroses ont egalement éte
exposes aux attaques par la meme population de Dendroctones et que la
predation sur les Dendroctones avait lieu.

References
Dyer, E. D. A. 1973. Spruce beetle aggregated by the synthetic pheromone frontalin. Can. J. For.

Res. 3: 486-494.
Kinzer, G. W., A. F. Fentiman, Jr.,

T. F. Page, Jr.,

R. L. Foltz, J. P. Vité, and G. B. Pitman.

1969. Bark beetle attractants; identification, synthesis and field bioassay of a new com-
pound isolated from Dendroctonus. Nature 221: 477-478.

Kline, L. N., R. F. Schmitz, J. A. Rudinsy and M. M. Furniss. 1974. Repression of spruce beetle
(Coleoptera) attraction by methylcyclohexenone in Idaho. Can. Ent. 106: 485-491.

Rudinsky, J. A., C. Sartwell, Jr., T. M. Graves and M. E. Morgan. 1974. Granular formulation
of methylcyclohexenone: an antiaggregative pheromone of the Douglas fir and spruce
bark beetles (Col., Scolytidae). Z. ang. Ent. 75: 254-263.

Nijholt, W. W. 1973. The effect of male Trypodendron lineatum (Coleptera: Scolytidae) on the
response of field populations to secondary attraction. Can. Ent. 105: 583-590.

J. ENTOMOL. Soc. Brit. COLUMBIA 72 (1975), DEc. 31, 1975 23

SOME CHIRONOMIDAE (DIPTERA) NEW TO
BRITISH COLUMBIA AND CANADA

ROBERT A. CANNINGS

Department of Zoology, University of British Columbia,
Vancouver

During recent research on the chironomid
fauna of saline lakes in the southern interior
plateau region of British Columbia, a number of
species new to Canada or British Columbia
were encountered.

The following list cites those species that
have been identified to date with certainty
and gives the water bodies from which these
insects have been taken in emergence traps.
Species new to Canada are identified in the
text by a double asterisk (**) and those new to
British Columbia by a single asterisk (*).

The lakes studies are shown in Table 1
and are the same as those considered by
Scudder (1969). Further details of the study
area and the ecology of the chironomid species
will be published later.

Family Chironomidae
Subfamily Tanypodinae
Tribe Macropelopiini
Subtribe Macropelopiina

*Derotanypus (Merotanypus)
(Malloch)

alaskensis

B.C.—Barnes L., Round-up L., L. Lyle, Boi-

tano u., L. Jackson, L. Greer, Rock L., Near
Phalarope, Westwick L., Sorenson L., Near
Opposite Crescent, Box 17, Barkley L.,
East L. and Box 27.

Previous records: Alaska, Yukon Territory,
Northwest Territories, Alberta, Sask-
atchewan and Manitoba (Roback, 1971).

Subtribe Procladiina

*Procladius (Procladius) dentus Roback

B.C.—Barnes L., Round-up L., L. Lye, Boitano
L., Rock L., Westwick L., Sorenson L., Near
Opposite Crescent, Barkley L. and East L.

Previous records: Alaska, Northwest Terri-
tories, Saskatchewan, Manitoba, Quebec
and Labrador (Roback, 1971).

*Procladius (Procladius) clavus Roback

B.C.—Barnes L., Round-up L., L. Lye and
Boitano L.

Previous records: Spence Bay and Ceillini
Lake, Northwest Territories (Roback, 1971).

Tribe Pentaneurini
*A blabesmyia (Karelia) peleensis (Walley)
B.C.—Barkley L., East L. and Box 27.

Previous records: Alberta and Ontario, Wis-
consin and Iowa east to New York and
south to South Carolina (Roback, 1971).

Subfamily Orthocladiinae
Tribe Orthocladiini

*Cricotopus abanus Curran

B.C.— Box 17, Barkley L., East L., and Box 27.

Previous records: Manitoba (Sublette and
Sublette, 1965; Sublette, 1967).

*Cricotopus flavibasis Mailoch

B.C.— Round-up L., L. Lye, Boitano L., L. Jack-
son, L. Greer, Rock L., Near Phalarope,
Westwick L., Sorenson L., Near Opposite
Crescent, Box 17, Barkley L. and East L.

Previous records: Alberta (Strickland, 1938)
and Illinois (Sublette and Sublette, 1965).

*Cricotopus trifasciatus (Meigen)

B.C.—L. Greer, Near Phalarope and Barkley L.

Previous records: Germany, Idaho, east to
Ontario and New York, south to Missouri
and Florida (Sublette and Sublette, 1965).

** Acricotopus nitidellus (Malloch)

B.C.—a single male from Sorenson L.

Previous records: Illinois and New York (Sub-
lette and Sublette, 1965; Sublette, 1970).

*Psectrocladius barbimanus Edwards

B.C.—Barnes L., Round-up L., L. Lye, Boitano
L., L. Jackson, L. Greer, Rock L., Near
Phalarope, Westwick L., Sorenson L., Near
Opposite Crescent, Box 17, Barkley L.,
East L. and Box 27.

Previous records: northern and western Europe

and Stoughton, Saskatchewan (Saether,
1969).

**Psectrocladius zetterstedti Brundin

B.C.— Box 27

Previous records: Sweden (Brundin, 1949).

First record for North America.

Subfamily Chironominae
Tribe Chironomini

*Chironomus atrella (Townes)

B.C.—one male from Sorenson L.

Previous records: Alberta to Prince Edward
Island and south to California, Colorado and
Massachusxetts (Sublette and Sublette,
1965).

*Finfeldia pagana (Meigen)

B.C.—Barnes L., Round-up L., L. Lye, Boitano
L., L. Jackson, L. Greer, Rock L., Near

24

J. ENTOMOL. Soc. BRIT. COLUMBIA 72 (1975), Dec. 31, 1975

Table 1. Location and characteristics of water bodies studied in the Cariboo and Chilcotin areas of
British Columbia. Names in parentheses are those used by Scudder (1969).

Area Mean depth Max. depth

Mean conductivity
(microhmos / cm.

Water body Location (ha) (m) (m) at 25°C)
Barnes L* 52°0’30’’N 122°28’00’°W 17.20 2.0 4.5 11816
(Box 47)

Round-up L.* 52 02 122 30°30 30.84 2.6 6.2 6885
(Phalarope?T)

L. Lye* _ 52 O1 122 29 30 46.50 2.8 5.4 6548
(Box 20-21T)

Boitano L.** 5157 122 08 80.70 2K 4.5 4108
L. Jackson* 52 00 122,27 30 5.83 1.4 2.3 2766
(Nr. Opposite

Box 4T)

L. Greer* 51 59 30 122 26 15.18 1.0 2:3 1602
(Box 897)

Rock L.* 51 58 122725 34.60 del 2.5 1496
Near 52 02 122,31 5.06 1.3 3.0 1334
Phalaropet

Westwick L.** 51 59 122,09 58.32 3 4.5 1287
Sorenson L.tt 52 00 122-10

Nr. Opposite 515930 12227 6.88 1.4 3.3 810
Crescentt

Box 177 51 59 30 122 26 30 2.67 hel 3.3 741
Barkley L.* 52 00 122 28 4.53 0:7 Zee 592
(Opposite Box 47)

East L.* 5s 9 30 122,26 27.03 1.9 6.5 372
(Racetrack?)

Box 27t o1 59 122-25 4.30 0.5 1.5 16

**Official names cited in the Gazetteer of Canada. British Columbia Canadian Board of Geograph-
ical Names, Ottawa (1953).

* Official names adopted on the Chilcotin Training Area Composite Map MCE 120 (Edition 2).
Mapping and Charting Establishment, Department of National Defence, Ottawa (1968).

+t Unofficial names used by Scudder (1969). The ‘‘Box’”’ series refer to duck nest boxes put up
near the water body by the Game Branch of the B.C. Department of Recreation and Conserva-
tion in the 1950s: other names are convenience descriptive terms used for the water bodies by
Scudder and his students over the years.

++Unofficial name used locally for the western half of the old Westwick L. which is now split into
two by a road. The name Westwick L. as used here refers to the lake to the east of the road.

Note: Characteristics of water bodies taken from Scudder (1969) and Topping (1969).

J. ENTOMOL. Soc. BRIT. COLUMBIA 72 (1975), DEc. 31, 1975 20

Phalarope, Westwick L., Sorenson L., Near
Opposite Crescent, Box 17, Barkley L.,
East L. and Box 27.

Previous records: Europe; Idaho, South
Dakota, Michigan and New York (Sublette
and Sublette, 1965). In Canada the only
other record is from Saskatchedwan (Driver,
1971).

*Cryptochironomus psittacinus (Meigen)

B.C.— Round-up L., L. Lye and Boitano L.

Previous records: Europe; Alaska to New
York and south to Oregon and Kentucky
(Sublette and Sublette, 1965).

*Cryptotendipes ariel (Sublette)

B.C.—Barnes L., Round-up L., L. Lye and

Tribe Tanytarsini

*Tanytarsus gracilentus Holmgren

B.C.—Barnes L., Round-up L., L. Lye and
Boitano L.

Previous records: northern Europe, Alaska and
Northwest Territories (Ellesmere Is.) (Sub-
lette and Sublette, 1965).

**Tanytarsus holochlorus Edwards

B.C.—Barnes L., L. Lye, Boitano L., Westwick
L., Sorenson L., Box 17, Barkley L. and
Box 27.

Previous records: Europe (Mundie, 1957).

ACKNOWLEDGEMENTS
I thank Dr. D. R. Oliver and Dr. J. E.
Sublette for identifyting the species. Dr. Oliver

Boitano L.
Previous records:
Sublette, 1965).

also kindly criticized the manuscript. The re-
search was supported by a National Research
Council grant to Dr. G. G. E. Scudder.

California (Sublette and

References

Brundin, L. 1949. Chironomiden und andere Bodentiere der Sudschwedischen Urgebirgsseen.
Rep. Inst. Freshwat. Res. Drottningholm 30: 1-914.

Driver, E. A. 1971. Range extensions and habitat data of two Chironominae ( Diptera: Chirono-
midae) from Saskatchewan. Can. Ent. 103: 1017-1019.

Mundie, J. H. 1957. The ecology of Chironomidae in storage reservoirs. Trans. R. ent. Soc. Lond.
109: 149-232.

Roback, S.S. 1971. The adults of the subfamily Tanypodinae (=Pelopinae) in North America.
Monogr. Acad. Nat. Sci. Philad. 17: 1-410.

Saether, O. A. 1969. Some Nearctic Podonominae, Diamesinae and other Orthocladiinae (Diptera: -
Chironomidae). Bull. Fish. Res. Bd. Canada. 170: 1-154.

Scudder, G. G. E. 1969. The fauna of saline lakes on the Fraser Plateau in British Columbia. Verh.
int. Ver. Limnol. 17: 430-439.

Strickland, E. H. 1938. An annotated list of the Diptera (flies) of Alberta. Canad. Jour. Res., Sect.
D, zool. Sci. 16: 175-219.

Sublette, J. E. 1967. Type specimens of Chironomidae (Diptera) in the Cornell University
collection. J. Kansas Entomol. Soc. 40: 477-564.

Sublette, J. E. 1970. Type specimens of Chironomidae (Diptera) in the Illinois Natural History
Survey collection, Urbana. J. Kansas Entomol. Soc. 43: 44-95.

Sublette, J. E. and M.S. Sublette. 1965. Family Chironomidae (Tendipedidae) in Stone et al. (ed.).
A catalogue of the Diptera of America north of Mexico. U.S. Dept. Agr. Handbook.
276: 1-1696.

Topping, M. S. 1969. Giant chromosomes, ecology, and adaptation in Chironomus tentans. Ph.D.
diss., University of British Columbia.

26 J. ENTOMOL. Soc. BRIT. COLUMBIA 72 (1975), Dec. 31, 1975

LIFE-CYCLE OF A SPIRAL GALL APHID, PEMPHIGUS
SPIROTHECAE (HOMOPTERA: APHIDIDAE), ON POPLAR IN
BRITISH COLUMBIA!

CHO-KAI CHAN ANDA. R. FORBES

Research Station, Agriculture Canada
Vancouver, British Columbia

ABSTRACT

Pemphigus spirothecae Pass. was inadvertently introduced into North
America only recently. Upon hatching in spring on lombardy poplar, the.
fundatrix feeds on a leaf petiole, which bends and then spirals into a spiral
gall. The fundatrix produces about 100 fundatrigeniae within the gall. These
produce winged sexuparae which leave the gall and settle on the poplar
bark, where they produce up to eight progeny, males and females. Each
female lays a single large egg which overwinters on the bark. This aphid

is thus monoecious and holocyclic.

INTRODUCTION

The gall aphid, Pemphigus spirothecae
Pass., was studied on lombardy poplar, Populus
nigra L. var. italica, on the campus of the Uni-
versity of British Columbia during 1973 and
1974. This aphid produces unique spiral galls
(Fig. 1) on the petioles of the leaves. P. spiro-
thecae is apparently common in Europe but
was found only recently in North America in
Quebec (Alleyne & Morrison 1974) and at about
the same time in British Columbia. Its life-
cycle in Europe has been described by Toth
(1939). The present stydy was undertaken to
determine the life-cycle of the aphid in British
Columbia and to describe the aphid-host plant
interaction.

DEVELOPMENT OF THE GALL

In general, the formation of a gall has an
early phase, a trophic phase, and a post-trophic
phase (Mani 1964). In the spiral gall of P. spiro-
thecae the early phase can be sub-divided into
three stages: bending, spiralling and swelling
(Gerhardt 1922); swelling of the gall continues
through the trophic phase. Upon emerging
from the egg, the fundatrix or stem mother,
begins to feed on the petiole of a leaf produc-
ing first bending (Fig. 2b) then spiralling until
three loose spirals have been produced (Fig. 2,
c & d). Subsequent swelling of the gall seals
the gall cavity and increases its size (Fig 2,
e,f & g).

The time taken to produce the three coils
on petioles of lombardy poplar outdoors at
Vancouver was 3-4 weeks, considerably longer
than the 6 days reported by Dunn (1960) for
attaining the same stage in the laboratory.
If the first instar stem mother dies while the
gall is forming, no further development takes
place and incomplete galls result with one or

‘Contribution no. 362, Research Station, Agriculture
Canada, 6660 N. W. Marine Drive, Vancouver, British Colum-
bia, V6T 1X2.

two coils. Subsequent feeding by the newly
enclosed fundatrix stimulates the coils of the
gall to grow laterally, sealing the walls. In-
crease in length of the coils expands the gall
and increases the size of the cavity.

The galls reach maturity in late August
and September, gradually changing from green
to orange-red or brown. When mature, the
galls measure about 15 x 13 x 9 mm. The gall
cavity is lined by numerous short, papillate
unicellular hairs, with some longer multicellular
ones among them. When the gall is mature,
one or two ostioles develop (Fig. 3) between the
coils to serve as emergence holes for the aphids,
or sometimes the coils loosen, producing a long
slit in the gall, allowing a mass escape of the
inhabitants. In this post-trophic stage, the
galls deteriorate and fall from the tree with the
leaves. The total life of a gall is from 20-25
weeks.

We could find no evidence that the presence
of a gall on a leaf weakened the leaf or reduced
its size. Galled leaves, however, fell from the
tree sooner than non-galled ones.

LIFE CYCLE OF THE APHID

In late March or April at Vancouver the
fundatrix emerges from the overwintered egg,
at a time when the young poplar leaves begin
to appear. The first instar fundatrix (Fig. 4)
is small, brownish green, and has very well
developed hind legs, 4-segmented antennae
(Fig. 4a) and normally developed labium and
stylets (Fig 5). In fact, its stylets are very
much like those of Myzus persicae (Sulzer)
(Forbes 1969) with each madibular stylet inner-
vated by two dendrites. The fundatrix settles
to feed on a leaf petiole, initiating the formation
of the gall. The fundatrix moults for the first
time as soon as the spiralling of the petiole has
been completed, or almost completed ie.,
about 3-4 weeks after hatching. After the
fourth moult the fundatrix is mature and starts
to reproduce parthenogenetically. The mature

at

COLUMBIA 72 (1975), Dec. 31, 1975

J. ENTOMOL. Soc. BRIT.

*
N
|
<
N
N
N
N

aC Oty

9

lombardy poplar.

Fig. 1. Fully formed spiral gall of Pemphigus spirothecae Pass. on the petiole of a leaf of
Fig. 2. Stages in the formation of the gall: a, a non-galled leaf; b, bending of the petiole

spiralling of the petiole; e, f, & g, swelling of the gall.

Fig. 3 Mature gall with an ostiole (arrow).

28 J. ENTOMOL. Soc. Brit. COLUMBIA 72 (1975), Dec. 31, 1975

Fig. 4. First instar fundatrix of P. spirothecae with an enlargement of an antenna (4a).
Magnification: whole aphid | |= 0.5 mm
antenna | —_____}= 0.1mm

Fig. 5. Transmission electron micrograph of a cross section of the stylets of a first instar

fundatrix. | |= lu

Fig. 6. Mature fundatrix with an enlargement of an antenna (6a).
Magnification: whole aphid Tmt RAD aS aaa a 018)
antenna pos 0.1 mm

Fig. 7. Mature fundatrigenia with an enlargement of an antenna. Magnification as for Fig. 6.

Fig. 8 Sexuparae inside an opened gall.

J. ENTOMOL. Soc. BRIT. COLUMBIA 72 (1975), Dec. 31, 1975

* RS
\S
H9sqy

9. Mature sexupara with an enlargement of an antenna (9a). Magnification as for Fig. 6.

Fig. 10. Mature male (sexuale) with an enlargement of an antenna (10 a). Note the rudimentary
mouthparts. Magnification as for Fig. 6.
Fig. 11. Mature female (sexuale) with an enlargement of an antenna (11a). Note the rudimentary

mouthparts. Magnification as for Fig. 6.
Fig. 12. Female laying her egg.
Fig. 13. An egg with wool-like wax.

20

30 J. ENTOMOL. Soc. BRIT. COLUMBIA 72 (1975), Dec. 31, 1975

fundatrix (Fig. 6) is pale yellow and has short
4-segmented antennae, (Fig. 6a) and well-de-
veloped labium and stylets.

At Vancouver the fundatrices mature be-
tween mid-june and the beginning of July.
During July and August each fundatrix pro-
duces about 100 progeny, the fundatrigeniae.
The mature fundatrigenia (Fig 7) is pale and
can be distinguished from the mature funda-
trix by its longer, 6-segmented antennae (Fig.
7a). The fundatrigeniae moult four times before
they start producing the sexuparae.

The sexuparae are produced in August and
September and are present in the galls (Fig. 8)
from early August until lat November. The
mature sexupara (Fig. 9) is winged and has 6-
segmented antennae with transverse secondary
sensoria on the third and fourth antennal seg-
ments (Fig. 9a). The head and thorax are black
and the abdomen is_ yellow-green. Each
sexupara produces a maximum of six females
and two males on the bark of the tree and then
dies. The females and males moult three times
in a period of 36-40 hours and then mate. The
male (Fig. 10) is small and pale green with
4-segmented antennae (Fig. 10a). The female
(Fig. 11) is also small with 4-segmented anten-
nae (Fig. lla) but the abdomen is long and
contains a single, very large egg (Fig. 12) which
is laid in the crevices of the bark or under the
lichen (Cetraria sp.) often found on the bark.
The newly laid egg (Fig. 13) is 0.55 x 0.28 mm
and is almost the size of the female’s abdomen.
It is white and covered by wool-like waxy secre-
tions from the abdominal wax glands. In 3 or
4 days the egg changes to light green and then
to a bright yellow-brown. The egg overwinters
on the bark.

The sexuales do not feed since they do not
have functional mouthparts. The labium is re-
duced to a small papilla and stylets are absent.
The rudimentary condition of the mouthparts
can be seen on the heads in the photomicro-
graphs of the antennae in Figs. 10 and 11.

Thus all the morphs of P. spirothecae are
found on the bark or in the galls on lombardy
poplar. The aphid is therefore monoecious and
holocyclic.

DISCUSSION

The formation of the spiral gall on the
petiole of lombardy poplar is a dramatic ex-
ample of the way in which aphids can change
the growth processes of plants for their own
advantage. The plant tissue completely sur-
rounds and encloses the fundatrix and her pro-
geny. Only late in the season does the gall open
and release the sexuparae.

Other species of Pemphigus living on poplar
produce markedly different galls. The form of
the gall, therefore must be due to the specific
feeding behaviour of the aphid when gall forma-
tion is initiated and to chemical substances
injected into plants with the aphid’s saliva
(Miles 1968). The details of the feeding be-
haviour of the fundatrix of P. spirothecae have
been described by Dunn (1960).

The spiral gall provides the aphid with an
environment protected from parasites, preda-
tors and weather conditions; only the sexuales
spend their entire life outside of the gall. Prob-
ably just as important to the aphid is the fact
that the galling apparently supplies the aphid
with improved nutrition by changing the
physiology of the plant (Forrest 1971).

References
Alleyne, E. H., and F. O. Morrison. 1974. Pemphigus spirothecae (Homoptera: Aphidoidea), an
aphid which causes spiral galls on poplar in Quebec. Canad. Ent. 106(11): 1229-1231.
Dunn, J. A. 1960. The formation of galls by some species of Pemphigus (Homoptera-Aphididae).

Marcellia 30 (Suppl.): 155-167.

Forbes, A. R. 1969. The stylets of the green peach aphid, Myzus persicae (Homoptera: Aphididae).

Canad. Ent. 101 (1):31-41.

Forrest, J. M. S. 1971. The growth of Aphis fabae as an indicator of the nutritional advantage
of galling to the apple aphid Dysaphis devecta. Ent. exp. & appl. 14 (4): 477-483.

Gerhardt, K. 1922. Uber die Entwicklung der Spirallockengalle von Pemphigus spirothecae ander
Pyramidenpappel. Z. Pflkrankh. 32: 177-189. (Seen in Rev. appl. Ent. A10: 492 (1922)).

Mani, M.S. 1964. Ecology of plant galls. Monogr. Biol. 12. Junk (The Hague).

Miles, P. W. 1968. Insect secretions in plants. Ann. Rev. Phytopathol. 6: 137-164.

Toth, L. 1939. Uber die Biologie der Blattlaus Pemphigus spirothecae Pass. Z. angew. Ent. 26 (2): |

291-311.

J. ENTOMOL. Soc. Brit. COLUMBIA 72 (1975), DEc. 31, 1975 31

THE STATUS OF CONOCEPHALUS FASCIATUS VICINUS
(MORSE, 1901) (ORTHOPTERA: CONOCEPHALIDAE)

JOHN E. R. STAINER'

ABSTRACT

It has been common practice to divide Conocephalus fasciatus (DeGeer,
1773) into two subspecies: C. f. fasciatus from eastern North America and
C. f. vicinus (Morse, 1901) from the west. The criteria for this division are
examined and evidence introduced to show that the name vicinus should
be suppressed and that the entire taxon should be called Conocephalus

fasciatus (DeGeer, 1773).

LITERATURE REVIEW

The name of this taxon has undergone many
changes since DeGeer (1773) described a tetti-
goniid from Pennsylvania which he called
Locusta fasciata. Thunberg (1815) set up the
genus Conocephalus which was intended to in-
clude, among others, the ‘‘cone-headed grass-
hoppers’ now placed in Neoconocephalus
Karny, 1907, and the ‘“‘meadow-grasshoppers’’
presently placed in the group. Audinet-Ser-
ville (1831) briefly described a_ genus,
Xiphidion, which included among its species
Xiphidion fasciatum (DeGeer). Burmeister
(1839) emended the suffix so that the name of
the genus became Xiphidium. These two names
were thereafter used more or less _inter-
changeably for the balance of the nineteenth
century.

Kirby (1890) listed four references to
Xiphidion and one to Xiphidium. A_ few
authors, including Kirby (1906), used the name
Anisoptera Latreille, 1829, for the same taxon.
Rehn (1907) re-examined the situation and
pronounced, as had Kirby (1906), that Cono-
cephalus hemipterus Thunberg was identical
with Gryllus conocephalus Linnaeus, 1758.
As no other specias had previously been desig-
nated as type of the genus, this made G. cono-
cephalus the type of the genus by tautonymy.
Kirby had not accepted the tautonymic nomen-
clature. When Rehn and Hebard (1915a, 1915b)
published their monograms on American
species of the genus, the name Conocephalus
became well established and it remains so to
the present day. DeGeer’s species is now known
as Conocephalus fasciatus (DeGeer).

Xiphidium vicinum was described by Morse
(1901) from the Pacific Southwest of the United
States of America, as a species similar to
X. fasciatum but with the ovipositor almost
constantly longer than in the latter species.
The ratio of hind femur to ovipositor was in-
dicated as being greater than in X. fasciatus.
Karny (1912) listed the two as separate species
of Conocephalus, but Kirby (1906) had already

'Present address: Dept. of Entomology, Macdonald Campus
of McGill University, Ste Anne de Bellevue, P.Q., Canada.

recognized the two as full species, placing them
in Anisoptera, presumably because of his lack
of acceptance of tautonymic names, as noted
above. The position of the “‘variety”’ productum
of Morse (1901) remained confused, probably
because of a lack of clarity in the original
description. Karny (1907, 1912) considered this
form to be a synonym of C. fasciatus, while
Kirby (1906) and Rehn and Hebard (1915)
both placed it under vicinus, which the latter
authors further considered to be but a sub-
species although he referred to Conocephalus
fasciatus (DeGeer). The next author to devote
much space to these members of Conocephalus
was Cantrall (1943, 1968) who used the full
trinomen of the eastern subspecies on both
occasions, thus implying acceptance of the
existence of another subspecies.

The ranges of the two groups were discussed
by Rehn and Hebard (1915). Subsequent papers
have made slight extensions in most possible
directions. C. f. fasciatus was said to range over
North America east of the Rockies and north
as far as southern Canada. C. f. vicinus was
considered to be restricted to the west: Califor-
nia, Oregon, Washington and the _ other
American states to the west of the Atlantic-
Pacific divide (except Alaska), and British
Columbia.

MATERIALS AND METHODS

Only dried insects were used in this study.
The measurements made were similar to those
used by Morse (1901) as criteria for separating
fasciatus from C. vicinus. Only females were
used because Morse was unable to separate the
males on morphological grounds. The measure-
ments of the males have been made as part of
another study but will not be discussed further
in this paper.

The lengths of the ovipositor and one hind
femur were recorded for each specimen. All
measurements were made with a ‘‘Wild M5”
stereo microscope equipped with a calibrated
ocular micrometer. Measurements for reason-
ably-sized series of specimens from various
individual localities were made and averaged

a2 J. ENTOMOL. Soc. BRIT. COLUMBIA 72 (1975), Dec. 31, 1975

and the ratio of femur III to ovipositor-length
calculated. The ratios were then plotted on a
base map of North America.

A separate set of measurements was made
for all other available females (isolated speci-
mens and very short series). These were
grouped by state or province and averaged.
The averages were plotted on the same map to
provide an independent confirmation of the
results from data obtained from the longer
series.

RESULTS

The results are summarized in the accom-
panying map and table. The sample numbers
(which were quite randomly designated) and
localities follow: (1) Sainte Anne de Bellevue,
Quebec, (2) Antelope Springs, California,
(3) Eugene, Oregon, (4) Ames, Iowa, (5) Rock
Co., Minnesota, (6) Scott Co., Minnesota, (7)
Saint Anthony Park, near St. Paul, Minnesota,
(8) Ottertail Co., Minnesota, (9) Republic,
Anoka Co., Minnesota, (10) Rockaway Beach,

Long Island New York, (11) Juniper, Florida,
(14) South Ohio, Nova Scotia, (15) Avoca,
Quebec, (16) Evans, Washington, (17) Gaines-
ville, Florida, (18) Pequaming, Michigan, (19)
Thomasville, Georgia, (20) Jemez Hot Springs,
New Mexico, (21) Milford, Beaver Co., Utah,
(22) Klamath Falls, Oregon, (23) Castlegar,
British Columbia, (24) Malta, Montana, (25)
Lac Serpent, Quebec, (26) Morgan Arboretum,
Sainte Anne de Bellevue, Quebec, (28) Dorion,
Quebec, (29) Point Pelee National Park, On-
tario, (30) Sandbanks Provincial Park, Prince
Edward County, Ontario, (31) Salmon Arm,
British Columbia, (32) Saint Claude, Manitoba,
(33) Delorraine, Manitoba, (34) Alexandria,
Ontario.

DISCUSSION

An examination of the map (Fig. 1) reveals
that the ratio of femur III to ovipositor reaches
a maximum in California and a minimum in the
north-eastern part of the range. With minor
variations, which may probably be attributed

TABLE 1
Sample Ovipositor Femur III Ratio
number n length (mm) SD length (mm) SD ovipositor /femur III
ih 94 a 0.40 10.8 0.69 .66
1 94 aol 0.40 10.8 0.69 .66
2 9 10.7 0.37 11.6 0.56 92
3 11 8.6 0.30 11.4 0.51 £75
4 12 8.6 0.52 11.8 0.87 .73
9) 14 9.3 0.57 11.6 0.64 81
6 9 8.3 0.59 10.7 0.78 .78
7 10 8.6 0.49 11.4 0.35 75
7) T3 8,9 0,38 11,5 0,48 od,
10 Jia 7.4 0.55 8 0.74 .63
11 19 8.5 0.49 W272, 0.82 .70
14 13 7.6 0.36 11.6 0.39 .65
15 31 (es: 0.30 10.8 0.42 .68
16 7 9.4 0:99 T3 0.37 83
al 13 8.4 0.33 L238 Occ, .68
18 16 8.6 0.37 11.8 0.64 As
19 12 on 0.54 13.3 0.7 .68
20 8 9.0 0.44 PEZ 0.4 .80
>| 13 10.6 0.34 12.0 0.4 .88
22 8 10.3 0.27 11.4 0.56 .90
23 13 eh) 0.45 11.6 0.37 85
24 4 8.8 0.36 11.8 0.66 75
25 40 7.4 0.33 eZ 0.67 .66
26 24 el 0.28 NET 0.59 .66
28 10 8.1 0.28 1221 0.33 .67
29 24 7.8 0.55 12.2 0.71 .64
30 a, fies) 0.43 Use 0.60 .67
31 15 eZ 0.28 11.5 0.32 .80
32 19 8.6 0.37 10.8 0.71 .80
33 8 9.4 0.71 11.5 0.55 .82
34 25 7.9 0.84 11.5 0.42 .69

Conocephalus fasciatus: sample size; lengths of femur III and ovipositor and their ratios. Sample

numbers as in accompanying list of localities.

J ENTOMOL. Soc. Brit. COLUMBIA 72 (1975), Dec. 31, 1975 30

Fig. 1. Conocephalus fasiatus: ratio of lengths, femur III to ovipositor. A single sample. © state
or provincial average.

34 J ENTOMOL.

to the small sample size, the ratio changes
steadily between the two regions. Similar
changes take place between California and
British Columbia and between California and
Mexico.

There were two independent sets of data
as described above. the same pattern was found
in the two separate sets of data, i.e., those from
the long series and those grouped by state or
province from individuals or short series. The
pattern that emerged may be described as indi-
cating a cline extending from a maximum
ratio in California-Utah to minimum at the
northern, eastern and, probably the southern
limits of the range. The lowest ratios were
found at the greatest distance from California;
that is, in the northeastern portion of the
range.

The existence of this cline calls into question
the utility of Morse’s name vicinus. Morse
had examined material only from New England
and California-Oregon and, apparently, no-
where between the two. he produced no usable
criteria for the separation of males and was
himself in many cases unable to distinguish
between vicinus and fasciatus males. It should
also be noted that, among other species of
Conocephalus, it is the males that are most
easily separated, the females often proving
difficult. Morse was able to separate his fe-
males by use of the femur III/ovipositor ratio,
but even this resulted in a “‘gray”’ area. A
ratio of 0.50 to 0.67 was supposed to indicate
C. fasciatus, while 069. to 0.95 was indicative
of vicinus. Specimens between 0.67 and 0.69
mightbe regarded as belonging to either. In

Soc. Brit. COLUMBIA 72 (1975), Dec. 31, 1975

practice, the ratios do not appear to have been
much used to separate the two taxa. Anything
from east of the continental (Atlantic-Pacific)
divide has been called C. fasciatus and that
from the west has been called vicinus, either
at the species or subspecies level. If one applies
Morse’s ratios to mid-western material, most
specimens from west of Illinois would have to
be called vicinus and there would be a very
wide band of overlap with fasciatus. Thus it
would be pointless to continue to recognize
eastern and western entities as meriting sepa-
rate names.

To end the confusion it is proposed to sup-
ress the name vicinus althogether and to refer
to the whole taxon as Conocephalus fasciatus
(DeGeer, 1773) regardless of geographical
differences.

ACKNOWLEDGEMENTS

A project of this type necessitates borrow-
ing specimens from many sources. In this case
thanks are due to the curators of about twenty
different institutions in North America who
lent material. In addition, the Entomology
Laboratories of the Academy of Natural
Sciences, Philidelphia, and of the Universities
of British Columbia and Idaho, and of the
Museum of Comparative Zoology, Harvard
University, kindly permitted the use of their
facilities. Financial assistance came in part
from a grant from the National Research Coun-
cil of Canada to Dr. D. K. McE. Kevan. Thanks
are also owed to Dr. Kevan for reading and
criticizing the manuscript and to Dr. T. J.
Walker for collecting a series of specimens from
Florida.

References
Audinet-Serville, J. G., 1831. Revue méthodique des insectes de l’ordre des Orthopteres; II. Anns.

Sci. nat. 22: 135-167.
Blatchley, w. S.,

1920. Orthoptera of Northeastern America with especial reference to the faunas

of Indiana and Florida; The Nature Publishing Company, Indianapolis.

Burmeister, H., 1839. Handb. der Ent., Berlin.
Cantrall, I. J., 1

943. The ecology of the Orthoptera and Dermaptera of the George Reserve,

Michigan; Mise. Publs. Mus. Zool. Univ. Mich., 54: 182 + X.
1968. An annotated list of the Dermaptera, Dictyoptera, Phasmatoptera and

Orthoptera. Mich. Ent. 1: 9.

Geer, C. de, 1773. Memoires pour servir a l’histoire des insectes, Stockholm.
Karny, H., 1907. Revisio Conocephalidarum. Abh. zool. bot. Ges. Wein IV (3): 1-114.

, 1912. Genera Insectorum 135: 7-13.

Kirby, W. F., 1890. On the employment of the names proposed for genera of Orthoptera, previous
to 1840. Scient. Proc. R. Dubl. Soc. 6: 556-597.

—_____, 1906. A synonymic catalogue of the Orthoptera. Brit. Mus. Longmans, London.

Morse, A. P., 1901. The Xiphidiini of the Pacific Coast. Can. Ent. XX XIII: 201 -205.

Rehn, J. A. G.,

1907. Orthoptera of the families Tettigoniidae and Gryllidae from Sapucay,

Paraguay. Proc. Acad. nat. Sci. Philad.: 370-395.

and Hebard, M.,

1915a. A synopsis of the species of the genus Conocephalus found in

North America north of Mexico. Trans Am. ent. Soc. XLI: 155-224.
___, 1915b. VI—A synopsis of the species of the genus Conocephalus found in
enCn south of the southern border of the United States. Trans. Am. Ent. Soc. XLI:

225-290.
Thunberg, C. P.,

1815. Hemiptorum maxillosum, Genera _ Illustrata,

Plurimusque novis

speciebus ditata ac descripta. Zap. imp. Akad. Nauk V: 218.

J. ENTOMOL. Soc. BRIT. COLUMBIA 72 (1975), Dec. 31, 1975

BOOK REVIEW
Lamb, K. P. 1974. Economic Entomology in
the Tropics. Academic Press, London, 195 pp.
£4.00.

In this brave and successful book the pub-
lisher presents something of a puzzle. Well
printed and illustrated on good quality paper,
it is elegantly hard-bound in AP livery; but it
is a small book which would fit into a paper-
back format no bigger than a thinnish Penguin.
Even as a reference and teaching text it must
surely soon be replaced by more detailed, re-
gional texts. Perhaps, hopefully, the present
hard-wearing library format means that it is a
trail breaker and the forerunner of a series for
graduate students and district agriculturists
based on crops or insect groups or major re-
gions. Any of these subdivisions is enough to
absorb several lifetimes of research and review,
but in a chauvinistic world, the last-named
may be the most promising.

The organization by chapters is as follows:
four pages on insects, good and bad; five pages
on classification based on the C.S.I.R.0.’s
Insects of Australia (1970); then short chap-
ters on primitive and some aquatic insects;
cockroaches and mantids; termites; Orthoptera
and Dermaptera; Hemiptera; Lepidoptera;
flies and fleas; beetles; Hymenoptera; the
ecology of pest control; insecticides; malaria;
and a summary of major pests of coffee, tea,
cotton, cocoa, sugar cane, rice and coconuts.
These, except for part of the rice crop, are cash

35

crops and export items. Missing, except for
passing mention, are pests of major local sub-
sistence crops: bananas, citrus, cassava,
pulses, millet, sorghum, mango, and maize.

The chapters on various orders include
tables of selected pests, with common names,
hosts, and distribution. Since keys are not pos-
sible, the tables exist in something of a
vacuum, and become almost unmanageably
long even when subdivided by hosts or groups
of crops attacked. For instance, there are tables
dealing with 50 Pyralids, 36 Noctuids, 31
scales, and 81 weevils; with distributions given
as e.g.: the Americas, Africa, India, or even
in desperation, pan-tropical. Prof. Lamb
assumes’ considerable familitarity with
scientific nomenclature. His English is clear
and scholarly and by no means condescending
or over-simplified. Mistakes, misspellings and
misprints are at an irreducible minimum. The
five to eight references with each chapter are
carefully chosen. Most are generalized works,
monographs and books rather than research
papers. Eleven of the 97 are in French, four in
German.

The dust jacket calls this: ‘‘A short, highly
condensed, immensely practical book . . . the
first broad review of economic insects in the
tropics.’’ As such it promises to be an invalu-
able starting point for problem solving, a teach-
ing text, and the basis for more detailed
successors.

H. R. MacCarthy

36 J. ENTOMOL. Soc. Brit. CoLuMBIA 72 (1975) Dec. 31, 1975

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JOU RNAL_

_ ENTOMOLOGICAL
SOCIETY of
BRITISH COLUMBIA

Issued December 31, 1976

ECONOMIC

IL SON, k FINLAYSON & CAMPBELL—Controlling the European
Ww worm oot bagg obscurus L. in British Columbia..... agency we damien ke aut eats as

4 sean of adult ladybirds patie Ae Goccinellidael preying on field
| pe oo of pea aphids (Homoptera: Aphididae) ita She Steg nee aes

TAXONOMIC
BES & CHO-KAI CHAN—The aphids (Homoptera: Aphididae) of
ish Columbia 4. Further additions & corrections ..............000 eee eeee . 57
RTH & FRAZER—Compilation of taxonomic catalogues by
ea a te aa eRe ce Gite San pon Sig aU eldla ry Wig « Wie Wierkio wie sw biace ebro v.40 OO
REVIEW - 0000-0. e ese cece eee sees eee cee ee ete eee Pe pee UREN 67

JOURNAL

of the

ENTOMOLOGICAL
SOCIETY of
BRITISH COLUMBIA

Vol. 73 Issued December 31, 1976

ECONOMIC

WILKINSON, FINLAYSON & CAMPBELL—Controlling the European
Wireworm Agriotes obscurus L. in British Columbia.................0000000. 3

GENERAL

FRAZER & IVES—Homalotylus californicus (Hymenoptera: Encyrtidae),
a parasite of Coccinella californica (Coleoptera: Coccinellidae), in British

CUMIN Hae aes te eae eo oc oe Sos, curse ore Sa aia Ce aoe AS RNG Wig ee Ihe ea 6
MYERS & CAMPBELL—Predation by carpenter ants: a deterrent to the

Spread omeinnabar MOth “c. ccsicd ewe AAieu sews eS 0s ced be deals bua sae edie els 7
FINLAYSON & CAMPBELL—Carabid & Staphylinid beetles from agricultural

land in the lower Fraser Valley, British Columbia ....................0.00000- 10
SCHENK, MAHONEY, MOORE & ADAMS—Understory plants as indicators

of grand fir mortality due to the fir engraver ............ 0.0 ccc cece cee ence 21
KULHAVY, SCHENK & HUDSON—Cone & seed insects of subalpine fir during a

year of low cone production in Northern Idaho ........... 0.0.00 cece eee e ee eee OD
FORBES—The stylets of the large milkweed bug Oncopeltus fasciatus

(Hemiptera: Lygaeidae) & their innervation ........ 0.0... cece ee eee eee eens 29

FRAZER & GILBERT—Coccinellids & aphids: a quantitative study of the
impact of adult ladybirds (Coleoptera: Coccinellidae) preying on field

populations of pea aphids (Homoptera: Aphididae) .............. 220000 ees 38)
TAXONOMIC
FORBES & CHO-KAI CHAN—The aphids (Homoptera: Aphididae) of
British Columbia 4. Further additions & corrections ...............200000000 05070
RAWORTH & FRAZER—Compilation of taxonomic catalogues by
COCDITA) DY UIC H ae ae ga lee a aNd Ora YP ta aa Pe 63
Bo IMBEU LAY LIES Vn erroueucy cies e uic a tu arte, aie ee csc, sls iace ae’ 6 Gece wa laws wleenls aeans Oe eke aoe ete 67

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976 |

Directors of the Entomological Society of
British Columbia for 1976-1977

President |

H. S. GERBER

B.C. Dept. of Agriculture,
Cloverdale

President-Elect
A. L. TURNBULL

Simon Fraser University,
Burnaby

Past President
J. R. CARROW

Pacific Forest Research Centre,
Victoria

Secretary-Treasurer

B. D. FRAZER
6660 N.W. Marine Drive, Vancouver, B.C. V6T 1X2

Honorary Auditor
D. G. FINLAYSON

Research Station, C.D.A., Vancouver

Editorial Committee
H. R. MacCARTHY

Vancouver
J. CORNER

Vernon

Directors

J. MYERS (2nd) R. CHORNEY (2nd) B. AINSCOUGH (2nd)
R. COSTELLO (1st) N. V. TONKS (1st)

Regional Director of National Society
J. P. M. MACKAUER

Simon Fraser University, Burnaby

J. ENTOMOL. Soc. Brit. COLUMBIA 73 (1976), DEc. 31, 1976 3

CONTROLLING THE EUROPEAN WIREWORM,
AGRIOTES OBSCURUS L., IN CORN IN BRITISH COLUMBIA

A. T. S. WILKINSON, D. G. FINLAYSON
AND C. J. CAMPBELL

Research Branch, Agriculture Canada
6660 N. W. Marine Drive, Vancouver, B.C.

ABSTRACT

Six insecticides at various rates and formulations, applied by three
methods over three seasons, were evaluated for controlling the European
wireworm, Agriotes obscurus L. in corn planted in silt loam. The insecticides
were in granular form, applied as a broadcast, in a band, or in the seed
furrow. Most of the materials, rates and methods gave good protection. In-
secticide applied in the furrow was placed either in contact with the seed, or
just ahead of it and mixed with soil. When it was in contact with the seed
the yield was slightly lower, indicating some phytotoxicity. The furrow
methods were the most economical in material and labour.

INTRODUCTION

Damage caused by wireworms to suscep-
tible crops such as corn and potatoes is in-
creasing in the lower Fraser Valley. The
problem is serious in corn grown for the fresh
market, canning and ensilage, especially near
Agassiz where the wireworm Agriotes obscurus
L. was accidently introduced from Europe
about 1900 and has become well established
(King et al. 1952; Wilkinson 1963). Much of the
infested land in this area has been treated with
the cyclodiene chlorinated hydrocarbons, aldrin
and heptachlor, which gave protection for at
least nine years following a single application
(Wilkinson et al. 1964). Later tests showed that
the small amounts of insecticide remaining in
the soil were still toxic to young wireworms
even 13 years after the soil was treated. In
many fields the wireworms were eradicated by
these chemicals but nearby headlands and road
allowances provided a continuing source of rein-
festation. Restoration of this wireworm to its
previous levels is slow because the adults do
not fly and the life cycle takes 3 to 4 years, so

that an infestation may take several years to
build up to economic levels. The worst problem
at present involves land that was not cleaned
up with the long-lasting chemicals of the late
1950s and early 1960s, but in time all the fields,
treated or not, will need treatment.

A series of tests of short-lived insecticides
and methods of application, were made during
several seasons to find an effective, economic
control. The most effective chemicals and the
initial rates were determined in the laboratory
and the field tests were done near Agassiz in
silt loam.

MATERIALS AND METHODS

1970 Experiment: The land was infested
with 80 A. obscurus per m? which destroyed
corn planted in May. On June 10, insecticides
were applied in randomized blocks replicated
four times. The granular insecticides were
broadcast evenly over the surface and worked
in to a depth of 10 cm. Oats, peas, and vetch
were planted since these crops can be grown
successfully on heavily infested land. The effect
of the treatment was determined in September

TABLE 1. Average numbers and percentage reduction of A. obscurus after broadcast soil treat-
ments with various insecticides, Agassiz, B. C., 1970.

Insecticide % granules Toxicant (Kg/ha) Wireworms/m? Control (/)
Fonofos 20 5.6 12.16 a** 84.8
Carbofuran 5 5.6 12.16 a 84.8
Carbofuran 10 5.6 14:53 4 81.8
Bux* 15 5.6 19.37 a 75.8
Check —_ 79.97 b _

* A 3:1 mixture of m-(1-methylbutyl)phenyl methylcarbamate and m-(l-ethylpropyl) phenyl

methylcarbamate.

** Values followed by the same letter are not significantly different (Duncan, 1955).

4 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976 |

by counting the wireworms in 10 cylindrical soil
cores taken at random from each plot with an
augur. Each core was 103 cm? by 38 cm deep.
The results are shown in Table. 1.

1974 Experiment: The population was 75.3
A. obscurus per m’. Granular insecticides were
applied in a band, in the furrow and by the
broadcast method. The purpose of adding the
band and furrow treatments was to reduce the
amount of insecticide and thus the cost. Carbo-
furan was not included in the 1974 and 1975
experiments because of instability in some
soils. Bux was withdrawn by the manufacturer.

In the band method the insecticide was

applied in a strip 30 cm wide at 18.6 g toxicant |
per 100 m of row then worked into a depth of |
10 cm. The corn was seeded in the middle of |
the band. In the furrow method the insecticide
was applied with the seed at 9.3 g toxicant
per 100 m of row. The treating and planting ©
was done May 30. In September any differences |
in yield were shown by counting and weigh-
ing the corn stalks from 10 m of row. Wire-
worms were counted by sifting the soil and
examining the roots in five samples per plot,
each 15 cm square by 20 cm deep, dug with a
spade, with a corn root at the centre of the
sample. The results are shown in Table 2.

TABLE 2. Growth and yields of corn and average numbers of A obscurus per corn root after
various treatments with four granular insecticides at Agassiz, B.C., 1974.

Insecticide % Method of Toxicant
granules Application (Kg/ha)
Fonofos 10 Broadcast 5.6
Counter! 15 Broadcast 5.6
Fonofos 10 Band 2.0
N 2596? 10 Broadcast D6
Counter 1 Furrow 1.0
N 2596 10 Furrow 1.0
Bay 92114? 10 Furrow 1.0
Fonofos 10 Furrow 1.0
Bay 92114 10 Broadcast 5.6
Check — —

Avg. wt. Avg. no. Avg.no. Avg. wt./
plants wireworms/ stalks/ 10 m row
(Kg) corn root 10 m row (Kg)
1.04 a oa 47.5 a 44.3 a
1.03 a 50a 44.0 ab 40.1 ab
1.02 a 1.40 ab 41.7 ab 37.9 ab
1.0la 1.40 ab 41.2 ab 36.6 ab
.96 ab 1.85 ab 45.0 ab. 36.5 ab
.93 ab 1.40 ab 46.7 ab 35.5 ab
.92 ab 3.30 b 38.5 be 32.2 be
.89 ab 95a 40.7 ab 31.3 be
.87 ab 1.50 ab 31.5 cd 23.6 cd
.80 b 6.25 c Zieoa 19.2d

'AC 92100 S-([tert-butylthio] methyl) 0,0, diethyl phosphorodithioate
*S(p-chlorophenyl) o-ethyl ethane phosphorodithioate
*] methylethyl 2 [[ethoxy{ (1 methylethyl) amino] phosphinothioyl/oxy] benzoate

1975 Experiment: The methods of appli-
cation were the same as in 1974 except fora
modification of the furrow method. To deter-
mine if the insecticide applied with the seed
caused phytotoxicity and reduced the yield,
a second method was included whereby the in-
secticide was applied just ahead of the seed.
Rates of 9.3 and 13.9 g of toxicant per 100 m
were tested. The efficacy was determined by
differences in the number of stalks, weight of
the yield in 6 m of row and in wireworms count-
ed by the method used in 1974. The treatments
were made and the corn was planted May 138;
it was harvested September 26. The wireworm
counts were made September 30 and October 1.
The results are shown in Table 3. The data
were examined by analysis of variance and the
results compared with Duncan’s Multiple
Range Test (Duncan 1955).

RESULTS AND DISCUSSION
Based on population counts the broadcast
treatments of granules in 1970 all gave good
control of wireworms (Table 1). There were no
significant differences between the efficacy of

the chemicals even in the two granular formula-
tions of carbofuran.

In 1974 the results showed that in general
the broadcast treatments were slightly better
than the band or furrow treatments (Table 2).
With the exception of the Bay 92114 broadcast
treatment all the chemicals and methods gave
significantly better yields than the control and
all significantly reduced the number of wire-
worms. The furrow treatment of Bay 92114
was slightly, but not significantly, better than
the broadcast treatment.

In 1975 all the treatments gave significant
reductions in the number of wireworms over the
control but the differences in yield were less
clear, although significant differences were ob-
tained. The broadcast treatments generally
reduced the wireworm population more than
did the furrow treatments. There were differ-
ences between the two furrow methods; most of
the treatments in which the insecticide was
applied with the seed had low yields, which in-
dicated some phytotoxicity (Table 3). The
heavy rate used in the furrow seemed to have
little effect on yield but did give a greater re-

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976

Table 3. Growth and yields of corn and average number of A. obscurus per corn root after various
treatments with three granular insecticides, Agassiz, B.C., 1975.

Insecticide % Method of Toxicant Avg. no. Avg. no. Avg. wt./
granules Application (kg/ha) wireworms/ stalks/ (Kg/ 6 m
corn root 6m row row)
N 2596 10 Furrow* 1.8 .15 ab 30.5 abc 22 Ana
Counter 15 Furrowt LeZ — 33.2 ab 21.8 ab
Fonofos 10 Broadcast 5.6 0.0a ole2 ab 21.4 abc
Fonofos 10 Furrow* 1.8 .5 abc 31.0 abc 20.9 abcd
Fonofos 10 Furrow* 1.2 1.05 ¢ 29.7 abc 20.7 abcd
Counter 15 Furrow* 1.8 .15 ab 34.5 a 20.4 abcd
Fonofos 20 Furrow* Ly .55 abc 31.2 ab 20.4 abcd
N 2596 10 Broadcast 5.6 .1 ab 29.0 abcd 20.0 abcd
N 2596 10 Furrowt 1.8 o 27.5 abcde 19.9 abcd
Counter 15 Furrow* 12 .75 be 28.5 abcde 19.5 abcde
Fonofos 20 Furrowt 12 — 24.0 cde 18.8 abcde
N 2596 10 Furrow* 1.2 .5 abc 31.2 ab 18.6 abcde
Counter 15 Broadcast 5.6 .3 abc 28.2 abcde 18.2 abcde
N 2596 10 Furrowt 12 — 26.5 bede 18.2 abcde
Counter 15 Furrowt 1.8 — 28.0 abcde 17.6 bede
Fonofos 10 Furrowt 1.2 = 26.5 bede 17.2 cde
Fonofos 10 Furrowt 1.8 = 22.7 de 16.9 de
Untreated -— == — 225 0 22.0e 15.5e

*Insecticide applied ahead of the seed in the furrow.

tInsecticide applied with the seed.

duction in the number of wireworms than the
low rate. Four months after application, dead
and dying larvae were found in the plots treat-
ed by the furrow methods, which indicated that
there was some persistence in the chemicals.
Fonofos, N 2596 and Counter appeared to give
about equal control regardless of method of
application.

Over the years the broadcast treatments
have given the greatest reduction in the num-
ber of wireworms and generally the best pro-
tection to the corn crop. The differences in con-
trol are not great but the cost of insecticide
for the furow treatment is only % that of the

broadcast. Further savings are made because
it does not require extra passes over the land to
apply the insecticide or one or more additional
diskings or rototillings to work in the insecti-
cide. The band treatment requires about twice
as much insecticide as the furrow treatment
and does not have the advantage of easy appli-
cation. The fact that wireworms were still being
killed four months after the furrow treatments
were made indicates that all the chemicals
tested in 1975 remained toxic when in high con-
centrations in the soil. Thus, chemicals applied
by this method will give protection during a
growing season.

References
Duncan, D. B. 1955. Multiple range and multiple F tests. Biometrics 11:1-42.

King, K. M. R. Glendenning and A. T. S. Wilkinson. 1952. A wireworm (Agriotes obscurus L.) Can.

Insect Pest Rev. 30:269-270.

Wilkinson, A. T. S. 1963. Wireworms of cultivated land in British Columbia. Proc. Entomol.

Soc. Brit. Columbia. 60:3-17.

Wilkinson, A. T. S., D. G. Finlayson and H. V. Morley. 1964. Toxic residues in soil 9 years after
treatment with aldrin and heptachlor. Science 143:681-682.

6 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976 |

HOMALOTYLUS CALIFORNICUS (HYMENOPTERA:
ENCYRTIDAE(, A PARASITE OF COCCINELLA CALIFORNICA
(COLEOPTERA: COCCINELLIDAE) IN BRITISH COLUMBIA

B. D. FRAZER! AND P. M. IVES?

ABSTRACT

We record the first occurrence in British Columbia of Homalotylus
californicus Girault, a parasite of Coccinella californica larvae. Parasitized
larvae are mummified and hardened with an abnormal bluish tint so they
are easily recognized in the field. The rate of parasitization in the field was
13%. The significance of this and related parasites of Coccinellids is

discussed.

In our study of the population dynamnics
of aphids on oats and alfalfa, we made daily
estimates of the abundance of coccinellids of
all stages in our field plots. The procedure for
estimating adult numbers will be reported else-
where. When a pupa was encountered its
species was recorded and a spot of paint was
placed beside it to avoid confusion later.

In 1975, first generation pupae of Coccinella
californica Mannerheim began to appear in
mid-july. On July 30 an unusual larva was seen.
It was moribund, hard, and mummified, but
attached to a leaf at its caudal end. It looked
like a larva about to pupate except for its dull
bluish colour. Such ‘blue’ larvae were also
identified with paint, and recorded separately.
The last blue larva was found on August 19
at the end of production of pupae in the field.

In all, 30 blue larvae were taken. From six
of these, emerged 5, 5, 5, 4, 3 and 3 adult
Homalotylus californicus Girault, but the re-
maining 24 mummified larvae failed to develop
further. When they were dissected, all con-
tained dead parasite larvae oriented longitudin-
ally more or less two abreast. Cocoons inside
those larvae from which H. californicus had
emerged were positioned similarly.

We recorded 201 normal pupae during the
time when the 30 parasitized larvae were found.
The rate of parasitization by H. californicus
was therefore estimated at 30/(201+30) or
13%. This value cannot easily by compared to
parasitization rates in the literature because of
apparent inconsistencies in the use of names.
The situation is similar to the confusion in use
of two species names of Homalotylus in Europe
(Hodek 1973); one species being solitary and
the other gregarious. Muesbeck et al. (1951)
and Peck (1963) refer to H. californicus as a

‘Research Scientist, Agriculture Canada, Research Station,
Vancouver, B.C. Canada, V6T 1X2.

“Post-Doctoral Fellow of the Institute of
Resource Ecology, University of B.C., Vancouver, B.C.
V6T 1E5.

Animal

subspecies of H. terminalis following Timber-
lake (1919) who did not find a constant diagnos-
tic character to separate the two. But Leonard
(1933) records that each pupa of Cycloneda
sanguinea L. had a single emergence hole cause
by H. terminalis, whereas our specimens had
many holes, one for each adult parasite.
Leonard recorded a parasitization rate for
C. sanguinea as 90%; Kulman (1971) found
that 26% of the Anatis quindecimpunctata
larvae he observed were parasitized, each pro-
ducing from 1 to 21 H. terminalis; and Kapur
(1942), and Miller and Thompson (1926, 1927),
recorded parasitization by H. t. californicus
as high as 42%, and by H. terminalis up to 50%,
respectively.

Yet in spite of the apparently low rate of
parasitization we observed, we believe the
H. californicus is potentially important. Pre-
liminary field experiments on the survival of
larval coccinellids show that less that 1% of
newly hatched, first instar larvae survive to the
fourth instar even when supplied with an
abundance of prey. the 13% mortality caused
by H. californicus is applied to those few sur-
viving fourth instar larvae. Since the parasite
is gregarious, the potential for increase and
detrimental impact on C. californica is great,
as shown by the high rates of parasitization
reported for other gregarious species.

Homalotylus spp. have been considered
by Hodek (1973) to be a very significant mor-
tality factor which may limit the entomopha-
gous efficiency of certain coccinellids in Europe,
India, the U.S.S.R. and Israel. However, most
species of Homalotylus are known to have
parasites of their own; perhaps this accounts
for their lack of more general and consistent
impact.

ACKNOWLEDGEMENTS
The specimens of Homalotylus californicus
were identified by Dr. C. M. Yoshimoto,
Biosystematics Research Institute, Ottawa.

|
|

J. ENTOMOL. Soc. Brit. COLUMBIA 73 (1976), Dec. 31, 1976 gk

Literature Cited

Hodek, I. 1973. Biology of Coccinellidae, Junk, The Hague, 260 p.
Kapur, A.D. 1942. Bionomics of some Coccinellidae, predaceous on aphids and coccids in

North India. Ind. J. Entomol. 4:49-56.

| Kulman, H. M. 1971. Parasitism of Anatis quindecimpunctata by Homalotylus terminalis. Ann.

Entomol. Soc. Amer. 64 (4):953-54.
26: 294
Florida Entomol. 10:40-46, 57-59.

aphid. Florida Entomol. 11:1-18.

Leonard, M. D. 1933. A braconid parasite of a Coccinellid new in Puerto Rico. J. Econ. Entomol.
| Miller, R. L. and W. L. Thompson, 1926. Life histories of Lady-beetle predators of the citrus aphid.

Miller, R. L. and W. L. Thompson, 1927. Life histories of Lady-beetle predators of the citrus

Muesbeck, C. F. W., K. V. Krombein and H. K. Townes, 1951. Hymenoptera of America North of
Mexico. U.S.D.A. agr. Monograph 2, 1420 p.
Peck, O. 1963. A catalogue of the Nearctic Chalcidoidae (Insecta: Hymenoptera). Can. Entomol.

Suppl. 30, 1092 p.

PREDATION BY CARPENTER ANTS: A DETERRENT TO
THE SPREAD OF CINNABAR MOTH

JUDITH H. MYERS AND BARBARA J. CAMPBELL

Institute of Animal Resource Ecology

and

Department of Plant Science
University of British Columbia, Vancouver

ABSTRACT

Cinnabar moth, an introduced biological control agent for tansy ragwort,
suffers heavy predation by carpenter ants in recently logged areas of
Oregon. We suggest that this mortality factor will reduce the spread of Cin-
nabar moth, thus preventing it from attacking a major seed source of tansy
ragwort and reducing its potential as a biological control agent. Single
larvae escape predation by ants more often than those in groups which
suggests that carpenter ant predation may select for larval dispersal.

The Cinnabar moth, Tria jacobaeae L.
(Arctiidae), has been widely spread from its
native Europe because of its potential as a
biological control agent against the weed Tansy
ragwort, Senecio jacobaea L. The success of
these introductions has ranged from ‘‘never
seen again’ to ‘‘abundant and thriving’’ after
15 years. At Abbotsford, B.C. the failure of the
first releases was attributed to heavy predation
by ground beetles (Wilkinson, 1965). In the
Gippsland vicinity of Victoria, Australia a
mecopteran, Harpobittacus nigriceps, heavily
predated a newly introduced Cinnabar popula-
tion and a nuclear polyhedral virus assured the
failure of the attempted introduction (Borne-
missza, 1966). The causes for the lack of
success of other introductions are not known
(Hawkes, 1968, Harris et al. 1975, Isaacson
1973).

Van der Meijden (1971) records an almost
perfect correlation between the log % mortality
of Cinnabar larvae and log density of Lasius

alienus, a predaceous ant. Further studies of
Lasius predation led Van der Meijden (1973) to
conclude that this ant may limit Cinnabar
numbers in some sand dune areas of the Neth-
erlands.

The following observations on predation by
ants were made as a by-product of experiments
designed to investigate larval dispersal in the
Cinnabar moth.

Study Area and Methods

The study was carried out in Linn County,
Oregon which lies between the western slope of
the Cascade Mountains and the eastern edge of
the Willamette Valley. Larvae were collected
from the Silbernagel population which was
studied by Isaacson (1973), and were trans-
ported to an area about 10 miles to the south on
Neal Creek Road. This area was logged within
the last 10 years so that stumps and fallen logs
were abundant on the steep hillsides. Tansy
ragwort is a common component of the herb-

8 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976 |

TABLE 1. Survival after 2 days of 3rd and 4th instar Cinnabar larvae introduced to tansy ragwort |

plants in groups of approximately 20 individuals.

0-10%

Frequency
Total Survival = 98/329=30%

aceous vegetation which has invaded this area,
and moth populations occur sporadically along
the road.

We chose the particular site for the study
because while abundant, large ragwort plants
occurred there, Cinnabar moth larvae were
lacking. We placed third and fourth instar
larvae on plants in groups of approximately 20
individuals, and recorded their movement from
the central plant to surrounding plants.

Percent Survival

11-25% 40% 65% 80-90%
3 2 1 3
Results

The disappearance rate of larvae from tansy
ragwort plants was exceedingly high (Table 1).
Observations revealed that the reason for this
disappearance was the activity of carpenter
ants, Camponotus sp., which nested in sur-
rounding stumps. Ants were seen to attack and
carry off the Cinnabar moth caterpillars but
to verify that the high rate of disappearance
was due to ant predation we set up groups of

TABLE 2. A comparison of Cinnabar larval survival on tansy ragwort plants to which ants had
access and those which were ant-free. Larvae placed on plants in groups of 10.

Original Number
Number After 2 Days

Percent Survival

larvae on plants with the base coated with
“stickum’”’ which prevented ants from crawling
onto the plants. The comparative rates of dis-
appearance of larvae on ant-free plants and
those to which ants had access are compared in
Table 2.

We observed that those Cinnabar larvae
which dispersed from the original plant had
better short term survival than those which re-
mained behind (Table 3). The effect of group
size was further tested by comparing the sur-
vival of single larvae to those in groups of 10.
While the survival of these individual larvae
was not as high as that of the natural dis-
persers (Table 3), it was almost double that of
larvae in groups of 10 (Table 2) over a 2 day
observation period.

Plants Without Ants Plants With Ants
49 40
43 9
86 23

Discussion

The relationship of the carpenter ant to the
Cinnabar larvae is an interesting one. The
Cinnabar larvae feed preferentially at the tops
of the plants on the flower buds. Their feeding
activity releases sap and the carpenter ants
will feed beside the caterpillars taking the sap
from the freshly cut surface. The two species
have been observed to coexist in this way.
However, suddenly an ant may attack a cater-
pillar. The usual result is that the caterpillar
falls from the plant, sometimes taking its
attacker with it. If other ants are nearby they
too will join in the attack. On one occasion
eight larvae lived two days on a plant that was
occasionally visited by ants. Suddenly the
attack began, and within one hour only three
remained the others having been carried off

TABLE 3. Survival after 2 days of Cinnabar larvae which dispersed naturally from original tansy
ragwort plants or were placed individually on plants.

Original Number
Number After 2 Days

Percent Survival

Larvae Larvae Placed
Dispersed On Individual
Naturally Plants

10 31
) 13
90 42

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976 9

by the carpenter ants.

Tansy ragwort is common in Oregon on the
extensively logged slopes of the Cascades and
of the Coastal mountains to the West. Although
in many areas Cinnabar moths have become
established (Nagel and Isaacson, 1974) the
presence of carpenter ants in this environment
will undoubtedly influence the success of the
natural spread of the moth to tansy ragwort
areas. This will interfere with the attempt to
destroy the source for tansy ragwort seed
which these areas provide.

Predation by carpenter ants gives rise to

a situation in which dispersal of Cinnabar
larvae could be at a strong selective advantage.
The general interpretation has been that in
areas of high predation, survival of dispersing
larvae will be low (Green, 1974). However, al-
though larvae are exposed to predation while
traversing from one plant to another, aban-
donment of the usual clumped distribution of
Cinnabar moth larvae might make_ the
difference between success and failure of estab-
lishment. If there is a genetic component to
dispersal one might predict strong selection for
dispersal in these areas.

References
Bornemissza, G. F. 1966. An attempt to control ragwort in Australia with the Cinnabar Moth,
Callimorpha jacobaeae (L.) (Arctiidae: Lepidoptera). Australian J. of Zoology 14: 201-243.

Green, W. Q. 1974. An antagonistic insect/host-plant system: The problem of persistence.
Ph.D. thesis. University of British Columbia.

Hawkes, R. B. 1968. The Cinnabar moth, Tyria jacobaeae, for control of tansy ragwort. J. econ.

Ent. 61:499-501.

Harris, P., A. T. S. Wilkinson, M. E. Neary, L. S. Thompson, and D. Finnamore. 1975. Establish-
ment in Canada of the Cinnabar Moth, Tyria jacobaeae (Lepidoptera: Arctiidae) for con-
trolling the weed Senecio jacobaea. Can. Ent. 107:913-917.

Isaacson, D. L. 1973. A life table for the Cinnabar Moth, Tyria jacobaeae, in Oregon.

Entomophaga 18: 291-303.

Nagel, W. D. and D. L. Isaacson. 1974. Tyria jacobaeae and tansy ragwort in Western Oregon.

J. econ. Ent. 67: 494-496.

Van der Meijden, E. 1971. Senecio and Tyria (Callimorpha) in a Dutch dune area. A study on an
interaction between a monophagous consumer and its host plant. Dynamics of Popula-
tions (P. J. den Boer and G. R. Gradwell, eds) (Oosterbeek, 1970): 390-404.

. 1973. Experiments on dispersal, late-larval predation, and pupation in the
Cinnabar Moth (Tyria jacobaeae L.) with a radio-active label ('% Ir). Neth. J. Zool.

23: 403-445.

Wilkinson, A. T. S. 1965. Releases of Cinnabar Moth, Hypocrita jacobaeae (L.) (Lepidoptera:
Arctiidae) on tansy ragwort in British Columbia. Proc. Ent. Soc. Br. Columbia. 62: 10-13.

10 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), Dec. 31, 1976

CARABID AND STAPHYLINID BEETLES FROM AGRICULTURAL
LAND IN THE LOWER FRASER VALLEY, BRITISH COLUMBIA

D. G. FINLAYSON AND C. J. CAMPBELL

Research Station, Agriculture Canada
Vancouver, British Columbia, V6T 1X2

ABSTRACT

Pit-traps were emptied every two or three days for two seasons in crop,
fallow, and grass plots to determine the species and population density of
Carabidae and Staphylinidae associated with agricultural land, and their
relationship with brassica crops. Half of the plots were enclosed by plastic
barriers and the beetles were trapped to extinction; half were not enclosed.
Thirty-three carabid and 16 staphylinid species were captured. The
dominant species was the small, generalized, European carabid predator,
Bembidion lampros, which had a population on crop and fallow land of about
29000/hectare. It was almost absent in grass. Other numerous carabids were
Harpalus aeneus, Calathus fuscipes, and Clivina fossor, all introduced
European spp., with populations of almost 2000, 5600, and 11000/hectare
respectively. The first and third of these were scarce in grassland but the
second was abundant. In plots of Brussels sprouts Aleochara bilineata, a
staphylinid, was effectively parasitic on root maggots, and averaged more
than 6000/hectare. Soil cores taken in October centred on a Brussels sprouts
plant averaged 26.4 Hylemya puparia per core of which 44% were parasitized

by A. bilineata.

INTRODUCTION

In 1916 Gibson and Treherne reported
several important parasites of root maggots.
They included several species of Carabidae,
which readily devoured eggs, larvae and
puparia of Hylemya brassicae (Bouche) in the
laboratory with other species of Staphylinidae
which they believed to be predacious. Included
also was the staphylinid Baryodma ontarionis
Csy. (= Aleochara bilineata Gyll.) a_ well-
documented parasite of the pupal stage of the
cabbage root maggot, H. brassicae. In-
vestigations of the biotic factors acting against
root maggots (Wilkes and Wishart 1953)
revealed a second staphylind parasite, A.
bipustulata (L) which parasitized considerably
fewer cabbage root maggots than A. bilineata,
but was four times as abundant on seed-corn
maggots H. platura (Meig.), a smaller host.

Wright (1956) and Wishart et al. (1956)
demonstrated the importance of carabid and
staphylinid beetles as predators of the im-
mature stages of the cabbage root fly,
especially of eggs. In 1960, Wright et al. ex-
posed untreated crops to the first generation of
the cabbage root fly and showed that predatory
beetles could greatly reduce the root maggots
and the crop damage. They discovered and
Coaker confirmed (1965) that the principal
predator in England was the small carabid,
Bembidion lampros (Hrbst.). To determine
which beetles were predators of eggs, Coaker
and Williams (1963) trapped beetles at
Wellesbourne, exposed them to cabbage root
fly eggs, and identified the egg-feeding species
by means of the precipitin test.

In 1972 and 1973, at Wellesbourne, England
and Agassiz, B.C., Finlayson et al. (1975)
examined the effects of several herbicides and
insecticides on carabid and staphylinid beetles
associated with minicauliflowers. The identity
and numbers of beetles present in the treated
and untreated plots were determined by pitfall
trapping, a method discussed at length by
Greenslade (1964). We investigated these
predator populations in the lower Fraser
Valley, mainly to determine their species and
population density in agricultural land, and
their relationship with cropping practices,
especially in brassicas.

METHODS

The work was done at the Agriculture
Canada Sub-station at Abbotsford. Three
agricultural conditions were sampled: crop,
fallow and grassland. In 1974 the plots were
400 m’. Three of the plots were open so that the
beetles could migrate freely, and three were en-
closed by 4 mil black polyethylene barriers 15
cm high. The barriers were made by folding a
strip of polyethylene, 60 cm wide, over a nylon
cord, stapling the cord and polyethylene to 15
cm stakes about 2.5 m apart, and anchoring the
bottom flaps by covering them with soil. In
1975, the plots were reduced to 100 m’. There
were 12 plots, two each of crop, fallow and
grass enclosed by the barrier and two each left
open.

The pitfall traps (pit-traps) were new tin
cans, 7 cm diam x 11 cm deep. A hole, 2 cm
diam, was cut in the bottom and covered with
40-mesh Lumite screen to allow rain water to
drain while retaining the beetles. The pit-traps

Ce
=

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976 11

were sunk in the ground with their rims level
with the soil surface. After heavy rains the pit-
traps were wiped clean around the upper 5 cm
to remove accumulated dirt and ensure a
smooth surface and thus to prevent the beetles
from climbing out of the trap and escaping. In
1974 predation by birds, especially crows, Cor-
vus brachyrhynchos hesperis Ridgway, in the
pit-traps set in grass led us to insert a cone-
shaped wire barrier of 1 cm mesh chicken net-
ting, which allowed the beetles to enter but
kept out the birds.

In 1974 there were 45 pit-traps in each 10 x
40 m plot, three rows of 15 traps spaced 2.5 m
apart. Grass and fallow plots were sampled
from April 26, but the cropped plots only from
July 5 because barriers could not be erected un-
til the Brussels sprouts crop, seeded June 17,
was established. In 1975 each plot contained 16
pit-traps, evenly spaced throughout the plot,
four in each of four rows, 2 m apart. The pit-
traps and barriers were set in place in late Mar-
ch. Brussels sprouts plants were transplanted
on April 1, and collecting started immediately.

The beetles were removed from the pit-traps
usually on Monday, Wednesday and Friday of
each week, identified and recorded. The beetles
were identified in the field or if necessary sub-
mitted to the Biosystematic Unit in Ottawa for
identification or confirmation. Beetles captured
in the enclosed plots were released outside the
barrier, but those captured in the open area
were immediately released within the plot. Thus
the total numbers captured in the enclosed area
revealed the number per unit area, whereas
those taken in the open area revealed their
habitat preference and the cycle of the adult
stage. The numbers of beetles of each species
were recorded separately on each collecting
period during the week, then summed to give a
weekly total for each species.

Soil samples were taken from the Brussels
sprouts plots at harvest in 1975 to determine
the percentage parasitism of the overwintering
population of puparia of H. brassicae. Ten sam-
ples were taken from each of the four plots of
Brussels sprouts. Each sample, 15 cm diam x
12 cm deep, with the topped plant as the centre
of the sample, was cut with a core sampler on
October 7. The core was placed in a cardboard
tub, 18 cm diam x 13 cm deep, sealed with a lid,
placed in the greenhouse for 21 days to allow
immature larvae to complete development, then
stored at 3°C for 100 days to break diapause in
H. brassicae. The puparia were recovered from
the soil cores by floatation, placed in 30 ml bot-
tles, and held at room temperature till the
emergence of a fly or a parasite. Those puparia
which did not produce either were dissected to
determine if parasites were present but had
failed to emerge.

RESULTS AND DISCUSSION
Thirty-three species of Carabidae and 16
species of Staphylinidae were taken from the
pit-traps. They are listed alphabetically in ac-
cordance with Hatch (1953, 1957).

Carabidae

Amara apricaria (Payk.)
Amara californica De}.
Amara familiaris (Duft)*
Amara obesa Say
Amara sp. (lunicollis group)
Anisodactylus binotatus (F)*
Agonum mulleri (Hbst.)*
Agonum subsericeum LeC.
Bembidion lampros (Hrbst.)*
Bembidion obscurellum Mots.
Bembidion petrosum Gebl.
Bembidion sp.
Blethisa oregonensis LeC.
Bradycellus congener LeC.
Bradycellus nigrinus De}.
Calathus fuscipes (Goeze)*
Calasoma tepidum LeC.
Carabus granulatus L.*
* Carabus nemoralis Mill.*
Clivina fossor (L.)*
Harpalus aeneus (F.)*
Harpalus opacipennis Hald.
Harpalus somnulentus De}.
Leistus ferruginosus Mann.
Loricera decempunctata Esch.
Notiophilus nitens LeC.
Pterostichus adstrictus Esch.
Pterostichus lama Men.
Pterostichus vulgaris L.*
Scaphinotus marginatus Fisch.
Scaphinotus angusticollis Mannh.
Trachypachus holmbergi Mots.
Trechus obtusus Er.*

Staphylinidae
Aleochara bilineata Gyll.*
Aleochara montanica Cys.
Atheta sp.
Hyponygrus angustatus Steph.*
Lathrobium sp.
Megalinus linearis O1.*
Morychus oblongus LeC.
Ocypus aeneocephalus DeG.*
Oxytelus rugosus (F.)*
Philonthus concinnus Grav.*
Philonthus fuscipennis (Mann)*
Philonthus varius Grav.*
Quedius curtipennis Csy.
Rugilus oregonus Csy.
Tachyporus chrysomelinus L.*
Tachyporus n. sp. near chrysomelinus
*Introduced species

Of the species captured, six carabids, A. famili-
aris, B. lampros, C. fossor, H. aeneus, P. vul-
garis and T. obtusus, and two staphylinids,
A. bilineata and O. rugosus are listed as preda-
tors of eggs of the cabbage root fly by Coaker

12 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DrEc. 31, 1976

TABLE 1. Carabid and staphylinid beetles taken from pit-traps in crop, fallow and grass plots,
enclosed by barriers at Abbotsford, British Columbia in 1974 and 1975.

Number of beetles per hectare

Cropped Fallowed Grass

1974 1975 1974 1975 1974 1975
Aleochara bilineata* 0 6200 16) 25 0 0
Amara spp. 1550 5350 3225 4650 325 2400
Anisodactylus binotatus 25 550 700 400 100 400
Bembidion lampros 3825 31100 16100 38500 215 650
Bembidion obscurellum 475 1950 1100 1850 0 0
Bembidion sp 25 0 350 0 1525 50
Calathus fuscipes 5875 550 7900 2800 9775 6800
Carabus nemoralis 50 0 25 100 100 50
Clivina fossor 175 15500 6400 10850 25 450
Harpalus aeneus 525 2000 4300 1600 325 150
Megalinus linearis* 275 1000 2025 650 1650 = 15100
Ocypus aeneocephalus* 0) 50 0 150 1050 1450
Philonthus concinnus* 100 950 375 250 300 3850
Philonthus fuscipennis* 75 50 50 0 1275 1400
Philonthus varius* 25 450 250 250 375 500
Pterostichus vulgaris 2275 1950 4625 700 500 700
Trachypachus holmbergi 0 600 125 650 0 50
*Staphylinidae

and Williams (1963). Although the smaller
species feed on eggs and probably early instar
maggots, the larger species of Amara,
Calathus, Harpalus, Pterostichus and Philon-
thus are capable of feeding on third instar
maggots and even of cracking the puparia.

Some species were considerably more abun-
dant than others. At Abbotsford, 19 species
(13 carabids and 6 staphylinids) appeared most
frequently; the other 30 species were taken
only occasionally.

The numbers of 19 of the common species
trapped have been collated so that those from
the barrier plots afford a reasonable estimate
of the numbers of each species per hectare
(Table 1). The numbers of the same species
from the open plots show preferences for any of
three habitats (Table 2). Because of the diffi-
culty in separating the three common Amara
spp. in the field (apricaria, californica, and
familiaris), they have been grouped under
Amara spp. All three species appeared in crop,
fallow and grassland, and appeared to show
only a slight preference for the cropped area.

The populations of Carabidae tended to be
highest on cultivated land. B. lampros,
B. obscurellum, C. fossor, and H. aeneus on
crop and fallow land averaged approximately
35,000, 1,900, 13,000 and 1,800 respectively
per hectare in 1975. These are very high num-
bers. The large species, especially C. fuscipes
and P. vulgaris, were present in cultivated
and sod land in comparable numbers. Con-

versely, the Staphylinidae appeared in greatest
numbers in grass, with M. linearis the most
common followed by P. concinnus, O, aeneoce-
phalus and P. fuscipennis. A. _ bilineata
appeared almost exclusively in the cropped
area. Its numbers are directly dependent on the
available numbers of its host, Hylemya
puparia.

When the numbers of beetles from the
barrier plots (Table 1) are compared with those
from the open plots (Table 2), it is obvious that
the increase in numbers results from recapture
of the same beetle. The numbers of the larger
species of beetles tended to be more uniform
from year to year.

Of the 19 species most commonly captured,
six were examined in greater detail to establish
the period of greatest frequency, the number of
generations per year and the adult cycle in re-
lation to generations of root maggots. The data
tabulated as weekly totals were plotted to show
the numbers captured per week in _ barrier
(Fig. 1) and open (Fig. 2), plots.

B. lampros and C. fossor were collected in
early spring, i.e. late March and very early
April. The peak of the cycle for B. lampros in
both years (Fig. 2a, 2g) centered around the last
week of May and the first week of June. It co-
incided well with the heavy oviposition of the
first generation of the onion fly H. antiqua
(Meig.), and the cabbage root fly. C. fossor
(Fig. 2d, 2j) was present at an early date but in
much smaller numbers. This species is consider-

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976 13

TABLE 2. Carabid and staphylinid beetles taken from pit-traps in crop, fallow and grass plots, not
enclosed by barriers at Abbotsford, British Columbia in 1974 and 1975.

Number of beetles per hectare

Cropped Fallowed Grass

1974 1975 1974 SMES 1974 1975
Aleochara bilineata* 300 4550 25 250 0 0
Amara spp. 11075 8500 4375 4500 350 2800
Anisodactylus binotatus 25 1800 400 1350 3795 950
Bembidion lampros 1500 108250 38950 73250 450 850
Bembidion obscurellum Sia 7650 2475 16300 0 0
Bembidion sp. 0 50 125 50 O75 300
Calathus fuscipes 47250 26800 18150 ~=—-13550 29750 29900
Carabus nemoralis 75 0 (3 0) EPs) 700
Clivina fossor 50 3400 3850 4500 250 500
Harpalus aeneus 3450 26000 28100 21100 350 750
Megalinus linearis* Sy AD) 1400 1900 900 3350 15650
Ocypus aeneocephalus* 125 50 375 0 1450 2400
Philonthus concinnus* 75 1100 100 500 625 6600
Philonthus fuscipennis* 75 150 175 200 1600 2950
Philonthus varius* 25 400 125 100 L75 800
Pterostichus vulgaris 7225 1050 2300 500 6550 3100
Trachypachus holmbergi 0 5850 ATES) 4300 0 50
*Staphylinidae

ed beneficial as a predator of eggs of root mag-
gots, but it is also listed as a minor pest, causing
damage to corn seed similar to that caused by
wireworms (Tsinovskii 1961). Some of the larger
species including H. aeneus, H. rufipes (found
in eastern Canada), and P. vulgaris, have also
been reported to feed on strawberry fruits
(Briggs 1957).

C. fuscipes (Fig. 1c,i and 2c,i) was much
more numerous in 1974 than it was in 1975.
It peaked late in the year. Specimens were
taken from April through October, but the
greatest number coincided with the oviposition
of the third generation of cabbage root fly.
Its ability to feed on mature maggots and
puparia could assist considerably in reducing
Over-wintering populations.

Amara spp., B. obscurellum and H. aeneus
were generally common at the beginning of the
growing season but were still present over the
full period of trapping. H. aeneus showed a
tendency towards a spring emergence period
(Fig. le,k) but the Amara spp. were most
numerous in late summer and fall (Fig. 2f,1).

From the soil cores taken in October 1975,
20 plants within the barrier plots yielded 432
puparia and 20 plants in the open plots yielded

623. Hylemya flies emerged from 52.5% and
50.6% of these respectively. From the puparia
from the barrier plots which did not produce
flies 193 A. billineata, 44.7%, and 12 (2.8%)
cynipid wasps, Trybliographa probably rapae,
were recovered. From the puparia from the
open plots which did not produce flies 267
(42.8%) A. bilineata and 41 (6.6%) Trvyblio-
grapha were recovered. It is important to note
that the 40 plants sampled averaged only 26.4
puparia each and that these plants, trans-
planted on April 1, withstood the attack of
three generations of root maggots without the
protection of pesticides. For that reason it is
essential that research be continued to develop
chemical controls for brassica crops which
are not detrimental to the parasites and preda-
tors of the root maggot complex.

ACKNOWLEDGEMENT
We thank Drs. D. E. Bright, J. M. Campbell,
A. Smetana, and C. M. Yoshimoto, Entomology
Research Institute, Agriculture Canada,
Ottawa for identifying the specimens; and Dr.
H. R. MacCarthy for his advice and review of
the manuscript.

Fig. 1. Population curves for six carabid beetles on crop, fallow and grass plots, enclosed by
barriers, at Abbotsford, B.C. in 1974 (a-f) and 1975 (g-1).

Fig. 2. Population curves for six carabid beetles on crop, fallow and grass plots, not enclosed by
barriers, at Abbotsford, B.C. in 1974 (a-f) and 1975 (g-1).

250

200

150

100

©
| ed
oy
rei
st
oF
S)
a)
A
7)
tc
D
rei
ise)
Ct
s
fe
PS
=)
ie
fe)
O
E
a2
ea
oO
fo)
YN
=
S)
=
)
=
Z
ca
ar)

NUMBER OF BEETEES

14

3 10 17 2431

3.10 17 2431

BEMBIDION LAMPROS

(BARRIER PLOTS)

BRUSSELS SPROUTS
FALLOW GROUND £4-------
GRASS) 0 9) Bese eeeee asses

14 2128 5 I2 19 26 2 9 16 2330 6 13 2027 4 Il 18 25 |
JUNE

7 |4 2) 28 5
JUNE

JULY AUGUST SEPTEMBER OCTOBER

BEMBIDION
OBSCURELLUM

l2 19 26 2 9 16 2330 6 13 2027 4 Ii 18 25 |
JULY AUGUST SEPTEMBER OCTOBER

WEEKLY

250

BEMBIDION LAMPROS

(BARRIER PLOTS)

I975

200

150

BRUSSELS SPROUTS
FALLOW GROUND -—-—------
GRASS

100

saceneng rece cessccecnccee

50

see aoe -—~.

4 fl 1825 2 9 1623306 1320274 It 1825 | 8&8 15 2229 5 12 19 26 3
APRIL MAY JUNE JULY AUGUST SEPTEMBER

in BEMBIDION OBSCURELLUM

4 {| 1825 2 9 1623306 1320274 Il 1825 ! 8 15 22295 12 19 26 3
APRIL MAY JUNE JULY AUGUST SEPTEMBER

COLLECTIONS

15

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976

NUMBER? OF BEETLES

Ww
°

3 10 17 243)
MAY

CALATHUS FUSCIPES

7 14 21 28 5
JUNE

20

l2 19 26 2 9 16 2330 6 13 2027 4 fl 18 25 | 4 fl 18 25 2 9 16 23 30 6

JULY

AUGUST SEPTEMBER OCTOBER APRIL MAY

CLIVINA FOSSOR

h
\ / me ‘
N
V/ v
3 10 17 2431 7 14 21 28 5 12 19 262 9 6 23 30 6 13 2027 4 Il 18 25 |
MAY JUNE JULY AUGUST SEPTEMBER OC TOBER APRIL MAY

WEEKLY COLL EC TIONS

CALATHUS FUSCIPES

ia seise

Po erorecneece

Pee eeccenes

I3 2027 4 Il 18 25 1 8 15 2229 5 1l2 I9 26 3
JUNE JULY AUGUST SEPTEMBER

CLIVINA FOSSOR

JUNE JULY AUGUST SEPTEMBER

J. ENTOMOL. Soc. Brit. CoLuMBIA 73 (1976), DEc. 31, 1976

NUMBER OF BEETLES

16

25 e A

HARPALUS AENEUS

20

3.10 17 2431 7 14 21 28 5 12 1926 2 9 16 2330 6 13 2027 4 Ii 18 25 | 4 fl 825 2 9 1623306 13 2027 4 tl 1825 | 8 15 22295 12 I9 26 3

MAY JUNE JULY AUGUST SEPTEMBER OCTOBER APRIL MAY JUNE JULY AUGUST SEPTEMBER

ae /' AMARA SPECIES AMARA SPECIES

25

20

oete
se

10 17 2431 7 142128 5 12 1926 2 9 16 2330 6 13 2027 4 I) 18 25 | 4 {| 1825 2 9 1623306 1320274 li 1825 | 8 15 2229 5 12 19 26 3
MAY JUNE JULY AUGUST SEPTEMBER OCTOBER APRIL MAY JUNE JULY AUGUST SEPTEMBER

WEEKLY COLLECTIONS

3

Li

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), Dec. 31, 1976

25

BEMBIDION LAMPROS

a (OPEN PLOTS )
200 / \

- r A I9 74

BRUSSELS SPROUTS

I v \ j \ GRASS

-— ~

~

3 10 17 2431 7 14 2128 5 12 19 26 2 9 16 2330 6 13 2027 4 fi 18 25 |
MAY JUNE JULY AUGUST SEPTEMBER OCTOBER

«| b

BEMBIDION OBSCURELLUM

NUMBER OF BEETLES

3 10 17 2431 7 1421285 12 1926 2 9 16 2330 6 13 2027 4 fi_ 18 25 |
MAY JUNE JULY AUGUST SEPTEMBER OCTOBER

FALLOW GROUND ------

250 Gg

200

BEMBIDION LAMPROS

(OPEN PLOTS)

I975

150

100 BRUSSELS SPROUTS
FALLOW GROUND

GRASS

50

4 fl 1825 2 9 (623306 1320274 It 1825 1 8 15 22295 12 I9 26 3
APRIL MAY JUNE JULY AUGUST SEPTEMBER

.|

50

' : ; BEMBIDION OBSCURELLUM

40
30

20

4 il 1625.2 9 1623306 !3 20274 || 18 25-1 8 15 22:29-5 (2
APRIL MAY JUNE JULY AUGUST

I9 26 3
SEPTEMBER

WE Eel GOL |b LIONS

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976

NUMBER OF BEETLES

18

r
500 C :

CALATHUS FUSCIPES

CALATHUS FUSCIPES

300

200

! :. ~, =. se.
Sasseanet Se suse ors tacos eet a free” sees Batazrecerseres oo ote a 5
3 10 17 2431 7 42128 5 l2 19 26 2 9 16 2330 6 13 2027 4 fl 18 25 | 4 | 825 2 9 1623306 1320274 It 1825 1! 8 15 2229 5 12 |I9 26 3
MAY JUNE JULY AUGUST SEPTEMBER OC TOBER APRIL MAY JUNE JULY AUGUST SEPTEMBER
A
1\
1 \
boo “i
!
20: | 20
' CLIVINA FOSSOR

CLIVINA FOSSOR

3 10 17 2431 7 421285 12 19 26 2 9 16 2330 6 13 2027 4 fi 18 25 | 4 f| 1825 2 9 1623306 1320274 Il 1825 | 8 15 2229 5 12 I9 26 3
MAY JUNE JULY AUGUST SEPTEMBER OCTOBER APRIL MAY

WEEKLY COLLECTIONS —it—~tS

rr

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), Dec. 31, 1976

NUMBER OF BEETLES

HARPALUS AENEUS

100

75

25

ease ten, \ a = a =
3 10 17 2431 7 421 285 12 19 26 2 9 16 2330 6 13 2027 4 I) 18 25 |
MAY JUNE JULY AUGUST SEPTEMBER OCTOBER

f

AMARA SPECIES

60
50
40
30

20

3 10 17 2431 7 421 285 12 19 26 2 9 16 2330 6 13 2027 4 Ii 18 25 |
MAY JUNE JULY AUGUST SEPTEMBER OCTOBER

60

HARPALUS AENEUS

50

40

30

20

4 {| 1825 2 9 |6 23306 132027 4 Il 1825 | 8 15 2229 l2 19 26 3
APRIL MAY JUNE JULY AUGUST SEPTEMBER
25
AMARA SPECIES
20
15
10
A
A 4 \ /
7 \ / a \ 7
5 7 \ SG \ /
\ i 7, i
; \ <7 ~ 4
‘ fF
aN ‘ 5 ‘i
4 {1 1825 2 9 623306 1320274 Il 1825 1 8 15 22295 12 I9 26 3
APRIL MAY JUNE JULY AUGUST SEPTEMBER

WEEKLY COLLECTIONS

20 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DrEc. 31, 1976

References
Briggs, J. B. 1957. Some experiments on control of ground beetle damage to strawberry. 44th Rep.
E. Malling Res. Sta. 1955-1956. 142-145.

Coaker, T. H. 1965. Further experiments on the effect of beetlé predators on the numbers of cab-
bage root fly, Erioischia brassicae (Bouché), attacking brassica crops. Ann. appl. Biol.
56: 7-20.
Coaker, T. H. and D. A. Williams. 1963. The importance of some Carabidae and Staphylinidae
as predators of the cabbage root fly, Erioischia brassicae (Bouché). Ent. exp. et appl.
6: 156-164.
Finlayson, D. G., C. J. Campbell and H. A. Roberts. 1975. Herbicides and insecticides: their
compatibility and effects on weeds, insects and earthworms in the minicauliflower crop.
Ann. appl. Biol. 79: 95-108.
Gibson, A and R. C. Treherne. 1916. The cabbage root maggot and its control in Canada with
notes on the imported onion maggot and seed-corn maggot. Canada Dep. Agr. Entomol.
Branch Bull 12. 58 pp.
Greenslade, P. J. M. 1964. Pitfall trapping as a method for studying populations of Carabidae
(Coleoptera). J. Anim. Ecol. 33:301-310.
Hatch, M. H. 1953. The beetles of the Pacific northwest. Part I: Introduction and Adephaga.
Univ. of Wash. Press, Seattle.
Hatch, M. H. 1957. The beetles of the Pacific northwest. Part I]: Staphyliniformia. Univ. of Wash.
Press, Seattle.
Tsinovskii, Ya. P. 1961. Clivina fossor L. a pest of corn in the environment of Latvian SSR.
Tr. Inst. Biol. Akad. Navk. Latviisk. SSR 20: 163-164 (#15685 Biol. Abs. 42: 1237, 1963).
Wilkes, A. and G. Wishart. 1953. Studies on parasites of root maggots (Hylemya spp.; Diptera:
Anthomyiidae) in the Netherlands in relation to their control in Canada. Tijdschr. PPziebt.
59: 185-188.
Wishart, G., J. F. Doane and G. E. Maybe. 1956. Notes on beetles as predators of eggs of
Hylemyia brassicae (Bouché). Canadian Entomol. 88: 634-639.
Wright, D. W. 1956. Entomology report. Rep. Nat. Veg. Res. Sta. Wellesbourne (1955) 47.
Wright, D. W., R. D. Hughes, and J. Worrall. 1960. The effect of certain predators on the numbers
of cabbage root fly (Erioischia brassicae (Bouché)) and on subsequent damage caused by
the pest. Ann. appl. biol. 48: 756-763.

|

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976 raat

UNDERSTORY PLANTS AS INDICATORS OF GRAND FIR

MORTALITY DUE TO THE FIR ENGRAVER:

By

J. A. SCHENK, R. L. MAHONEY, J. A. MOORE, AND D. L. ADAMS?

ABSTRACT

Mortality of grand fir trees, caused by the fir engraver, Scolytus
ventralis, was monitored during 3 years on ten 0.1 acre (0.04 ha) circular
plots in each of nine stands in northern Idaho. Understory vegetation
was sampled on each plot on the basis of circular subplots of 0.03 acre
(0.012 ha). Analyses showed four species to be strongly correlated with
high and two with low tree mortality. The interaction between these
groups of plant species provided a variable that increased as the pro-
portion of high to low hazard plants increased. Various linear and non-
linear expressions were tested between the two plant groups and their
interaction regressed against killed trees per acre. The plant group
interaction term accounted for the most variation (r’=0.914) and
produced the lowest standard error of the estimate (1.55). The equation
for this variable took the form Y=2.291 + 0O.1llex, where X=plant
group interaction. This equation provides an indication of the susceptibility

of grand fir stands to mortality caused by the fir engraver.

Grand fir, Abies grandis (Dougl.) Lindl., is
a major component of the grand fir - western
larch - Douglas-fir type in the northwestern
United States and southern British Columbia
(Fowells 1965). In Idaho, this species com-
prises half (874 M acres) (349.6 M ha) of the
total acreage occupied by the spruce-fir group
of types (Wilson 1962).

Numerous insect species attack grand fir,
but most of them cause little damage and are
of relatively minor economic importance. The
western balsam bark beetle, Dryocetes confusus
Sw., and the fir engraver, Scolytus ventralis
LeConte, are the principal bark beetle pests
(Fowells 1965). Epidemic infestations of the
fir engraver are sometimes severe, but rela-
tively localized and may be correlated with epi-
demics of the Douglas-fir tussock moth,
Orygia pseudotsugata (McD.) (Berryman 1973).
As an example of their severity, Stevens (1971)
reported that about 37,000 grand fir trees were
killed in 1954 on 6,000 acres (4800 ha) of the
Cibola National Forest in New Mexico.

Parasites and predators may help to con-
trol the fir engraver in some years (Massey
1966, Ashraf and Berryman 1970), but
generally are considered ineffective in prevent-
ing outbreaks (Stevens 1971). Chemical control

‘Published with the approval of the Director, Forest, Wild-
life, and Range Experiment Station, University of Idaho,
Moscow as contribution No. 18. Supported in part by McIntire-
Stennis funds and Potlatch Corporation, Lewiston, Idaho.

*Professor, Research Technician, Research Associate, and
Professor, respectively, College of Forestry, Wildlife and Range
Sciences, University of Idaho, Moscow, Idaho.

methods under forest conditions are considered
by most workers to be limited because of the
wide variation in the pattern of attack and
injury to the host tree. Little or no benefit is
gained by chemically destroying fir engraver
broods in trees under mass attack, unless those
broods in top-killed and ‘‘patch’’ attacked
trees (having the potential to sustain or re-
generate an epidemic) are also identified and
destroyed (Keen 1952, Struble 1957, Stevens
1971).

Silvicultural methods probably offer the
best possibility for minimizing losses. This
approach requires cultural practices that re-
move trees predisposed to attack, and the
maintenance of stand vigor and resistance
through regulation of density and composition.
Attainment of these objectives necessitates a
stand hazard rating system that will help forest
managers to assign treatment priorities. The
system should be based on data easily obtained
during the taking of standard timber inven-
tories.

It has been demonstrated that, in the
northern Rocky Mountains, the subordinate
plant unions reflect differences in site charac-
teristics (Daubenmire and Daubenmire 1968).
Thus, it seemed likely that the presence or
absence of certain understory plant species
or species groups could indicate site conditions
favorable or unfavorable to high mortality
caused by the fir engraver. A plant species
group as used here is a collection of plants with
similar relationships to a specified variable.

The study was conducted in three experi-
mental areas (replicates), each consisting of
three study sites, established on lands of the

22 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976

Potlatch Corporation in northern Idaho. Two
replicates (Gold Creek and Lost Creek) are
located in Abies grandis/Pachistima myrsinites
habitat types in Latah County and the third
replicate (Jaype) is located in a Thuja plicata/
Pachistima myrsinites habitat type in Clear-
water County. In each study grand fir com-
prises between 63% and 76% of the stems per
acre of more than 3 inches dbh.

Ten circular plots each of 0.1 acre (0.04 ha)
were systematically located with a random
start within each of the nine study sites. Grand
fir mortality attributable to the fir engraver
was monitored in each plot for 3 years (1972-
1974). The total mortality per acre caused by
the fir engraver in each study site was then
calculated.

Understory vegetation was sampled on each
0.1-acre plot during late summer of 1974, using
0.03-acre (0.012 ha) circular subplots with
witnessed and staked plot centers. These veg-
etation plots were offset 18 feet from the 0.1-
acre plot centers to avoid the disturbance
resulting from frequent visits to the main plot
centers. All perennial shrubs, forbs, and gram-
inoids on each plot were recorded. An ocular
estimate of percent cover with low and tall
shrub species also was recorded for each plot.

Within any given study site, the subord-
inate plant complex was not influenced by
topography. We calculated the frequency or
percentage of the total number of understory
vegetation plots occupied by each herbaceous
and shrub species at each study site, and also
the average percentage cover for each shrub
species.

The frequencies or average percentage cover
of about 50 plant species were evaluated by
means of correlation matrices, using killed trees
per acre during three years as one variable and,
as the other, frequency of a herb or shrub
species, or the average percentage cover of a

shrub... We assumed that the composition of the
subordinate plant complex and its relationship
to the site would remain unchanged during the
three years in the absence of outside disturbance
and considering only perennial plant species.
Based on this assumption, plant data collected
at the end of the mortality period were used to
indicate a relationship to mortality in stands
where fir engraver populations were likely to be
present. Those species showing direct or in-
verse correlation coefficients of 0.80 or more
were subjectively accepted as indicating high or
low mortality caused by the fir engraver. Six
species were thus selected for further analyses.

Results

Four of the six plant species had frequen-
cies that were directly correlated (group A),
and two had frequencies that were inversely
correlated (group B), with killed trees per acre
during the three years (Table 1). Additional ana-
lysis showed a high degree of correlation be-
tween the frequency of a given plant species and
the frequency of other species having a similar
(direct or inverse) correlation. The frequency
of each group was then calculated for each
study site, based on the percentage of the total
number of understory vegetation subplots
within each study site in which any single mem-
ber species of the plant group occurred.

The interaction between the frequencies of
the two plant species groups produced a var-
iable that increased with the proportion of
group A or high hazard to group B or low
hazard plants. This is expressed by:

PGI=fA/1 + fB
where:
PGI=plant group interaction
fA=frequency of occurrence of plant
species in group A.
fB=frequency of occurrence of plant
species in group B.

Table 1. Correlation coefficients for plant species correlated with grand fir trees killed
per acre by the fir engraver during 3 years, in northern Idaho, 1974.

Plant species variable

Common name

Usual habitat1/ r

Carex deweyana Schw.
Arenaria macrophylla Hook. Sandwort
Satureja douglasii (Benth.) Breq.
Holodiscus discolor (Pursh) Maxim.
Clintonia uniflora (Schult.) Kunth.

Chimaphila umbellata (L.) Bart.

Yerba buena
Oceanspray
Blue-bead lily

Pipsissewa

Dewey’s sedge Moist woodlands to forest openings 0.886
Moist to dry, shaded to open woods 0.812
Coniferous woods 0.825
Open dry to moist woods 0.946
Moist coniferous woods ~0.822
Under conifers in woods - 0.820

1/Scientific name, common name and usual habitat from Hitchcock and Cronquist 1973.

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976 23

To develop a mathematical expression that
would relate understory vegetation variables
to trees killed per acre by the fir engraver
during the three years, we tested various linear
and non-linear expressions of plant species
groups A and B, and plant group interaction, re-
gressed against trees killed per acre. The best
mathematical equations for these variables
took the following form:

Y=1.922 - 0.809X 1? + 1.713X 4 (1)
Y=15.045 - 0.136X » (2)
Y=2.291 + 0.11le%3 (3)

where:
Y=trees killed per acre by the fir engraver

during 3 years (KTA)

X, =frequency of occurrence of plant species
in group A

X»=frequency of occurrence of plant species
in group B
X3=plant species group interaction
(X;/1+ Xe)

The correlation coefficients for equations
1—3 are 0.954, -0.917 and 0.956, and their
standard error of the estimates are 1.634, 1.765,
and 1.550 respectively. The variable that ac-
counted for the most variation and also produc-
ed the lowest standard error of the estimate
was plant group interaction (equation 3) which
accounted for 92% of the variation in KTA, and
is significant at an oc |level of .01.

Discussion

It is noteworthy that the plant species in
group A are considered seral and those in group
B are considered climax species when the sub-
ordinate plant union is Pachistima myrsinites
(Daubenmire and Daubenmire 1968). Thus, the
presence of group A species indicates a site
presumably less conducive, and the presence
of group B species indicates a site more con-
ducive, to the maintenance of favorable mois-
ture conditions and vigor of grand fir.

The value of the relationship reported here
is its use as a means of ranking sites support-
ing grand fir according to their potential sus-
ceptibility. The level of mortality is depend-
ent upon stand variables, upon the intensity of
stress imposed on the site by adverse abiotic
factors, and upon the population levels of the
fir engraver. Other predisposing factors include
the presence of root disease (Partridge and
Miller 1972), and the reduced ability of trees
to produce traumatic resin canals (Berryman
1969, Berryman and Ashraf 1970).

In practice the subordinate plant union
would be sampled at each plot center during the
regular timber inventory, using 0.03-acre circu-
lar plots, and recording the presence of each
plant species group. At each plot, a plant
species group would be recorded as present if
any of the member species were present. The
plant group interaction term (PGI) would be
calculated and used as the independent variable
in equation 3 to indicate the susceptibility of
the stand of grand fir to mortality caused by
fir engraver.

Table 2. Correlation matrix between the frequencies of plant species in two groups,

northern Idaho, 1974.

y/x 1 2 3 4 5 6

1 1.000

2 0.796 1.000

3 0.898 0.767 1.000

4 0.887 0.738 0.905 1.000

4) -0.783 -0.702 -0.701 -0.833 1.000

6 -0.912 -0.775 -0.973 -0.885 0.613 1.000

Plant Group B
5. Clintonia uniflora (Schult.) Kunth.
6. Chimaphila umbellata (L.) Bart.

Plant Group A
1, Holodiscus discolor (Pursh) Maxim.
2. Carex deweyana Schw.
3. Arenaria macrophylla Hook.
4. Satureja douglasii (Benth.) Briq.

24

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976

Acknowledgements and James E. Jewell, Professor, Assistant Pro-
The authors acknowledge the assistance of fessor, and Graduate Assistant, University of

Frederic D. Johnson, Douglass M. Henderson, Idaho, respectively, in plant species identifica-

tion.

Literature Cited

. Ashraf, M. and A. A. Berryman. 1970. Biology of Sulphuretylenchus elongatus (Nematoda:

Sphaerulariidae), and its effect on its host, Scolytus ventralis (Coleoptera: Scolytidae).
Can. Entomol. 102: 197-213.

. Berryman, A. A. 1969. Response of Abies grandis to attack by Scolytus ventralis (Coleoptera:

Scolytidae). Can. Entomol. 101: 1033-1041.

______i*d'Y73. Population dynamics of the fir engraver, Scolytus ventralis (Coleoptera:
Scolytidae), I. Analysis of population behaviour and survival from 1964 to 1971. Can.
Entomol. 105: 1465-1488.

and M. Ashraf. 1970. Effects of Abies grandis resin on the attack behaviour

and brood survival of Scolytus ventralis (Coleoptera: Scolytidae). Can. Entomo. 102:
1229-1236.

. Daubenmire, R. and J. B. Daubenmire. 1968. Forest vegetation of eastern Washington and

northern Idaho. Wash. State Univ., Agr. Exp. Sta. Tech. Bull. 60, 104 pp.

. Fowells, H. A. 1965. (ed.). Silvics of forest trees of the United States. U. S. Dept. Agr., Agr.

Handbk. 271, 762 pp.

. Hitchcock, C. L. and A. Cronquist. 1973. Flora of the Pacific Northwest. U. of Wash. Press.,

730 pp.

. Keen, F. P. 1952. Insect enemies of western forests. U.S. Dept. Agr., Misc. Publ. 273, 280 pp.
. Massey, C. L. 1966. The influence of nematode parasites and associates on bark beetles in the

United States, Bull. Entomol. Soc. Amer. 12: 384-386.

. Partridge, A. D. and D. L. Miller. 1972. Bark beetles and root rots related in Idaho conifers.

Plant Disease Reptr. 56: 498-500.

. Stevens, R. E. 1971. Fir engraver. U. S. Dept. Agr., Forest Service, Forest Pest Leafl. 13, 7 pp.
. Struble, G. R. 1957. The fir engraver, a serious enemy of western true firs. U.S. Dept. Agr.,

Prod. Res. Rept. 11, 18 pp.

. Wilson, A. K. 1962. Timber resources of Idaho. U.S. Dept. Agr., Forest Service, Intermt.

Forest and Range Exp. Sta., Forest Survey Release 3, 42 pp.

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976

CONE AND SEED INSECTS OF SUBALPINE FIR
DURING A YEAR OF LOW CONE PRODUCTION IN
NORTHERN IDAHO!

By
D. L. KULHAVY, J. A. SCHENK, AND T. J. HUDSON?

College of Forestry, Wildlife and Range Sciences
University of Idaho, Moscow, Idaho

ABSTRACT

Cone and seed insects destroyed 29 percent of the seed crop of subalpine
fir (Abies lasiocarpa) in the Freezeout Mountain area of northern Idaho
in 1972 during a year of low cone production. Larvae of a coneworm,
Dioryctria abietivorella destroyed 12 percent of the seed crop, accounting
for 42 percent of the total insect damage. A newly discovered midge pest,
a species of Dasineura, destroyed 11 percent of the seed crop, amounting to
40 percent of the total insect damage. The dipterans, Hylemya abietis,
Earoymia sp., and Asynapta keeni, and the chalcid wasp, Megastigmus
lasiocarpae, together destroyed 4 percent of the seed crop. Unknown causes
accounted for 1.5 percent of the total seed destruction. X-ray was used to
estimate seed lost to M. lasiocarpae and Dasineura sp. Regression equations
are given relating cone length (mm), and the seeds on the axial surface, to
total seeds. Sound and damaged seeds on the axial surface were highly
correlated with the totals of sound and damaged seeds, respectively, in the

25

cone.

INTRODUCTION

Insects inhabiting cones and seeds of sub-
alpine fir, Abies lasiocarpa (Hook.) Nutt., have
received little attention. Keen (1958) listed five
species of insects that cause damage to sub-
alpine fir cones: the fir coneworm, Dioryctria
abietella (Denis and _ Schiffermueller) (=
D. abietivorella (Grote)); a cone maggot,
Earomyia aquilonia McAlpine; two species of
seed chalcids in the genus Megastigmus; and a
cone midge, Asynapta keeni (Foote). Hedlin
(1974) states that E. aquilonia destroys most
of the seeds in infested cones in British
Columbia, and that the subalpine-fir chalcid,
Megastigmus lasiocarpae Crosby, is not a
serious pest. He constructed a key to the
insects damaging cones in British Columbia.
Moyer and Parker (1973), and Kulhavy, et al.
(1975) presented a list of insects reared from
these cones in Utah and Idaho. Kulhavy (1974)
also constructed keys to the damage and to the
insect pests of subalpine fir cones in Idaho.

Several methods are available to evaluate
the damage within a cone and the impact on
the seed crop. Cones can be halved longitudin-
ally and counts made of insect-damaged,

‘Published with the approval of the Director, Forest, Wild-
life and Range Experiment Station University of Idaho, Moscow
as contribution number 37. Supported in part by MclIntyre-
Stennis funds’’.

2Graduate assistant, Professor, and _ scientific aide,
respectively. This research is a portion of a Master’s thesis by
the senior author.

3An r” of 0.92 was obtained from a regression of seeds
from one-half of a cone to total seeds within a cone.

aborted, sound and the total seeds on the ex-
posed axial surface (Winjum and Johnson
1960, McLemore 1961, and Bramlett and
Hutchinson 1964). Seed-infesting insects may
be detected by x-ray and dissections (Speers
1968, Fedde 1973). This paper reports on
damage by cone and seed insects of subalpine
fir in a year of very low cone production in
northern Idaho, and on the reliability of estima-
ting the damaged, sound, and the total
numbers of seeds in cones.

Subalpine fir cones were collected from early
July through early September, 1972 from
a 1.0 x 0.3 km. area in the Freezeout Mountain
region of Shoshone County, Idaho. The collec-
tion area, primarily an Abies lasiocarpa/
Xerophyllum tenax habitat type (Daubenmire
and Daubenmire 1968), has a slope of less than
10 percent to the southwest with an average
elevation of 1800 m. From each of 15 cone
bearing trees in the study area, 15 to 20 cones
were collected for insect rearing and damage
evaluation. These cones represented about 15
to 20 percent of the production in the area. The
average height of the sampled trees was 9.3 m
(range 3.1 to 13.7 m). The ages, taken at 1.3m
height, averaged 27 years (range 20 to 40 years)
and diameters averaged 20.0 cm (range 4.5 to
34.8 cm). Cones collected were placed either in
one-gallon, single-light-source rearing cartons
at 24°C, or dissected for insect damage. In the
former case, the emerged adults were identi-
fied by specialists and included in a checklist
(Kulhavy, et al. 1975), and in a key to damage
(Kulhavy 1974).

26 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976

From the 250 cone sample, 72 were com-
pletely disected within two weeks after collec-
tion for insect damage and seed estimation.
These cones were cut in half lengthwise using a
modified cone-knife cutter, and the numbers
of insect-damaged seeds were counted on the
exposed axial surface. Seeds were then hand
extracted from one-half of each cone’ (the half
selected at random by the toss of a coin),
counted and the seedwings removed. The seeds
were then placed in plastic petri dishes and
x-rayed for seed-infesting insects. The radio-
graphs were made in Faxitron® Model 804
self-contained X-ray system at 15 kVP for 8 to
10 seconds using Polaroid® Type 52 Land film.
The film was then developed for 10 to 15
seconds and coated with Polaroid print coater.
The number of seed-infesting insects was
counted and added to the damage caused by
other insects. This value was regressed against
the observed axial damage to estimate total
insect damage.

The cone length (mm), width (mm), and axial
seed count were regressed against the total
number of seeds within one-half of a cone to ob-
tain an estimate of the sound and total number
of seeds within a cone. Observations on life
history and behavior of the various species also
were recorded.

RESULTS
Dioryctria abietivorella (Grote), fir coneworm

Larvae of this pyralid infested 20 percent of
the examined cones and destroyed 45.7 percent
of the seeds in the infested cones. It was the
most destructive of all species, and caused
41.6 percent of the total insect damage,
destroying 12.0 percent of the seed crop.
Damage by D. abietivorella has been described
by Keen (1958) and their feeding in subalpine
fir cones is similar to that of related species in
other trees species. The larvae often bore from
one cone to another and through previously
infested cones, leaving large masses of granular
frass on the exterior of cones held together
by webbing. Damaged cones turn brown and
brittle by early August.

Larvae of D. abietivorella are behaviorally
distinct from other lepidopteran pests of cones.
When exposed, a mature larva immediately
begins sealing its tunnel by spinning silk across
the opeing, adding frass pellets to the lattice,
then more silk. The behavior observed was
similar to that seen in construction of pupal
cells although the latter are lined with addition-
al silk. A new species of parasitic Diptera in
the genus Lixophaga (Tachinidae) was reared
by us from larvae of D. abielivorella. The
impact of this parasite is not known.

Dasineura sp., seed midge
Estimates of damage by the newly-discov-
ered cecidomyiid pest of subalpine fir seeds

were obtained from radiographs and seed
dissections because the larvae feed internally
in the seeds or underneath the seed coat. They
destroyed 11.4 percent of the seed crop and
accounted for 39.2 percent of the total insect
damage. Mature larvae of this species are
readily distinguished on radiographs from
larvae of the seed chalcid, Megastigmus lasio-
carpae. Late instar M. lasiocarpae larvae are
distinclty ‘‘C’’ shaped and tapered at both
ends, whereas larvae of Dasineura are straight
or curved in the seeds, but not tapered.

This species overwinters as mature larvae
but no pupae or adults were recovered. About
10 percent of the larvae were parasitized by a
small, black, braconid wasp.

Asynapta keeni (Foote)

The larvae of this cecidomyiid were more
abundant (700) then those of any other species.
However, they accounted for only 1.2 percent of
the total insect damage and destroyed 0.4
percent of the seed crop by resin exudation.
The life cycle of the species in cones of sub-
alpine fir is the same as it is in cones of grand
fir, Abies grandis (Douglas) Lindley, (Kulhavy
1974). Adults emerge in late August or the
following spring.

Hylemya abietis (Huckett)

One larva of this anthomyiid infested one
subalpine fir cone and destroyed 32 seeds. This
amounted to one percent of the insect-caused
loss, or 0.3 percent of the seed crop. Larvae
when removed from cones collected later became
sluggish and constricted. They overwinter in
puparia in the soil and adults emerge the follow-
ing spring.

Earoymia sp.

Larvae of this lonchaeid caused 3.9 percent
of the insect damage and destroyed 1.3 per-
cent of the total seed crop in 1972. Seeds mined
by the larvae become flat, resinous and dark
brown. Only a very small amount of fine frass
is produced. After the mature larvae leave a
cone they move frantically until they find a
suitable pupation site in the litter or soil. The
larvae travel by three methods: (1) they wiggle
the entire body, causing a rolling, twisting
motion; (2) they alternately constrict and
lengthen the body segments, resulting in a
forward motion; and (3) they grasp fleshy areas
near the posterior spiracles with one or both
mouthhooks, which constricts the body into a
“C” shape with the midbody segments
flattened dorso-ventrally. When the mouth-
hooks are released, the larva is propelled for a
distance of 8 to 15 cm. This snapping motion
was stimulated in the laboratory and observed
in the field, and has been reported previously
for E. aquilonia by R. W. Reid as cited by
McAlpine (1956).

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEC.

ol, 1976 27

TABLE 1. Summary of regression analyses for predicting total, filled, and damaged seeds in
subalpine fir cones, northern Idaho, 1972 (n=72).

Dependent’ Independent
Variables Variables Intercept

1] Length (mm.) -50.4
Yy Width (mm.) -82.7
Yq Length, Width 62.2
«I Axial seeds (Total) -21.6
Yo Axial sound seeds 14.0
Y3 Axial damaged seeds 9.2

** Significantly different from zero at a=.01

Standard
error of
Regression estimate Coefficient of
Coefficient (Sy.x) Determination (r’)
2.09 19.6 .6055**
6.86 25.0 1313 a
1.96, 01.7 19.7 .6073**
4.88 23.9 .4120**
3.47 28.0 .4668**
2.55 15.5 .6777**

1 Yy =Total seed in one-half of a cone; Y2=total sound seeds in one-half of a cone;

Y3=total damaged seeds in one-half of a cone.

Megastigmus lasiocarpae Crosby

Larvae of this torymid destroyed 2.2 per-
cent of the seed crop, which has 7.4 percent of
the insect-caused seed loss. Damage by this
seed-infesting chalcid was estimated from
radiographs and_ seed_ dissections. Our
observations agree with those of Keen (1958)
who suggested that the species has a one year
life cycle snychronized with cone development.
The eggs are deposited in the seeds early in
cone devlopment and the larvae feed singly.
Only one larva develops if more than one egg
is deposited within a seed. Overwintering occurs
as mature larvae or pupae, and adults emerge
the following spring. An undetermined por-
tion of the population entered extended
diapause in 1972 and emerged in 1974.
Unknown causes

These accounted for 1.5 percent of the total
seed destruction.
Estimation of Seed Production and Damage

The number of seeds within subalpine fir
cones can be reliably estimated (r’=.6055,

a=.01) from the cone length (Table 1). Neither
cone width, nor the inclusion of both cone
length and width improved the fit. Similarly,
expressing the independent variables in
logarithms, or fitting a second degree poly-
nominal failed to significantly increase the fit.

The number of damaged seeds/cone also can
be reliably estimated (r’?=.6777, a=.01) from
counts of damaged seeds on an axial section
(Table 1). However, the axial slice technique
did not provide as good an estimate of the total
number of seeds/cone (r’=.4120), or the num-
ber of sound seeds/cone (r?=.4668). Means and
standard deviations for all variables are shown
in Table 2.

DISCUSSION

Every cone dissected from the Freezeout
Mountain area had at least one seed destroyed
by insects. Insects destroyed 29.1 percent of
the total seed crop during a year of very poor
cone reproduction. This loss is magnified by the
high percentage of aborted seeds, the naturally
low viability of subalpine fir seeds (USDA

TABLE 2. Means and standard deviations for all variables for subalpine fir cones,
northern Idaho, 1972.

Variable Mean Standard Deviation
Length (mm) 737 11.5
Width (mm) 28.7 yAE |
Axial seeds (Total) 27.8 4.1
Axial sound seeds fit Tel
Axial damaged seeds 9.1 On
Total sound seeds Ble 38.0
Total damaged seeds 32.6 27.1
Total seeds 114.2 31.0

28 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), Dec. 31, 1976

1974) and the cyclic nature of cone crops.
Desiccation of the seeds adversely affects
survival and seedling establishment during
the first season of growth. In the Freezeout
Mountain area, the establishment of seedlings
was further hindered by the light intensity
(USDA 1965) which exceeded 50 percent full
sunlight. The similarity and proximity of the
insect pests of grand fir cones (Kulhavy 1974,
Kulhavy et al., 1975) indicate that the infesta-
tions probably were from overwintering or
emigrating insects. The most destructive insect
species, the coneworm, is an ubiquitous pest
of cones and was also the most destructive
pest of grand fir cones (Kulhavy 1974, Kulhavy
and Schenk in press).

To obtain a reliable estimate of loss to cone
and seed insects, damage by the insects feed-
ing internally must be taken into account.
Thus, a portion of the seeds should be
examined by radiography or dissected to esti-
mate the damage. Although reliable estimates
were obtained of the total damage from the

number of damaged seeds on the axial surface,
and of total seeds per cone from the cone
length, Kulhavy, (1974) has shown that there is
high variability over the range of grand fir.
Similar variability in subalpine fir is likely.
Thus, the equation for predicting seeds in sub-
alpine fir cones should be tested at different
levels of cone production and insect populations
and over a broader geographic range before
applying it indiscriminately.

The loss of seeds to insects, coupled with
the cyclic nature of cone crops and the
generally poor germination of subalpine fir,
are factors that should be considered before
planning a timber harvest where natural re-
generation is desired.

ACKNOWLEDGEMENTS
We thank Drs. R. W. Stark and E. R.
Canfield, University of Idaho, and P. J.
Gravelle, Potlatch Corporation, who reviewed
the manuscript, and Drs. R. J. Gagne’, G.
Steyskal, and B. D. Burks who provided insect
identifications.

LITERATURE CITED
Bramlett, D. L., and J. G. Hutchinson. 1964. Estimating sound seed per cone in shortleaf pine.
U.S. Dept. Agr. Forest Serv. Res. Note SE-18. 2 pp.

Daubenmire, R., and J. B. Daubenmire. 1968. Forest vegetation of eastern Washington and
northern Idaho. Wash. State Univ. Agr. Exp. Sta. Tech. Bull. No. 60. 104 pp.

Fedde, G. F. 1973. Impact of the balsam woolly aphid (Homoptera: Phylloxeridae) on cones and
seed produced by infested Fraser fir. Can. Entomol. 105:673-680.

Hedlin, A. F. 1974. Cone and seed insects of British Columbia. Pacific Forest Res. Cen.,

Victoria, Brit. Col. 63 pp.

Keen, F. P. 1958. Cone and seed insects of western forest trees. U.S. Dept. Agr. Misc. Bull.

No. 1169. 168 pp.

Kulhavy, D. L. 1974. Cone and seed insects of grand and subalpine firs in northern Idaho. College
of Forestry, Wildlife and Range Sciences, M.S. thesis, University of Idaho. 79 pp.

Kulhavy, D. L, J. W. Dale, and J. A. Schenk. 1975. A checklist of the cone and seed insects of
Idaho. Forest, Wildlife and Range Experiment Station, Univ. of Idaho, Info. Ser.

No. 6. 28 pp.

Kulhavy, D. L. and J. A. Schenk. 1976. An evaluation of damage by cone and seed insects of
grand fir in northern Idaho. Univ. of Idaho, Dept. of Entomol. 50th Anniversary Pub.

(in press).

McAlpine, J. F. 1956. Cone-infesting Lonchaeids of the genus Earomyia Zett, with descriptions of
five new species from western North America (Diptera: Lonchaeidae). Can. Entomol.

88: 178-196.

McLemore, B. F. 1961. Estimating pine seed yields. U.S. Dept. Agr. Forest Serv. SE Exp.

Sta. Rep. No. 134. 2 pp.

Moyer, M. M., and D. L. Parker. 1973. A revised list of seed and cone insects collected from native
conifers in the Intermountain Region. Branch of Forest Insect and Disease Prevention
and Control. U.S. Dept. Agr. Forest Serv., Ogden, Utah. 15 pp.

Speers, C. F. 1968. Insect infestation distorts Fraser Fir seed tests. U.S. Dept. Agr. Forest Serv.

Tree Planters’ Notes 18:19-21.

U.S. Dept. Agr. 1965. Silvics of forest trees of the United States. U.S. Dept. Agr. Forest Serv.

Handbook No. 271. 762 pp.

U.S. Dept. Agr. 1974. Seeds of woody plants in the United States. U.S. Dept. Agr. Handbook

No. 450. 883 pp.

Winjum, J. K., and N. E. Johnson. 1960. A modified knife-cone cutter for Douglas fir seed studies.

J. Forest. 58:487-488.

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976 29

THE STYLETS OF THE LARGE MILKWEED BUG, ONCOPELTUS
FASCIATUS (HEMIPTERA: LYGAEIDAE , AND THEIR
INNERVATION’

A. R. FORBES

Research Station, Agriculture Canada,
Vancouver, British Columbia

ABSTRACT

Sections of the stylets of the large milkweed bug were examined in the
electron microscope. They differ from those of 29 spp. of Homoptera studied
earlier, in having: flanges on the maxillary stylets that engage grooves in
the mandibular stylets; three large and three small dendrites in the central
duct within the mandibular stylets; and a large salivary canal.

INTRODUCTION

The large milkweed bug, Oncopeltus
fasciatus (Dallas), is a widely used research
animal since it is reasonably large and can be
reared easily in the laboratory throughout the
year. Its widespread usage prompted a review
of published information on its morphology,
physiology and behavior (Feir 1974). No in-
formation on the structure of its stylets is in-
cluded in this review, nor are there other repor-
ts on their fine structure. The present paper
describes the stylets of this bug and compares
them with the stylets of some Hemiptera
(Suborder Homoptera) studied previously.

MATERIALS AND METHODS

The large milkweed bugs were from colonies
maintained in the laboratory at the University
of British Columbia.

The stylets were dissected from the bugs
and immediately fixed simultaneously for 1 hr.
on ice in 2% osmium tetroxide and 4%
glutaraldehyde, both in 0.1 M cacodylate buf-
fer, washed in 0.1 M cacodylate buffer (pH 7),
post-fixed in 2% osmium tetroxide in the same
buffer for ’2 hr, dehydrated in ethanol, and em-
bedded in Epon 812 by the method of Luft
(1961). The sections were cut with glass knives
on a Reichert Om U2 ultramicrotome, mounted
on grids with carbon-collodion supporting films
and stained with uranyl acetate and lead
citrate. They were examined with Philips 200 or
300 electron microscopes.

RESULTS AND DISCUSSION

The piercing-sucking organs of the large
milkweed bug consist of a pair each of man-
dibular and maxillary stylets. Each stylet has
an enlarged base within the head capsule and
an elongated shaft mostly outside the head. Ex-
cept at the bases, the mandibular stylets en-
velop the maxillary stylets closely, so that in a
cross section of the stylet bundle (Fig. 1), the

‘Contribution No. 390, Research Station, 6660 N. W. Marine
Drive, Vancouver, British Columbia, V6T 1X2.

mandibular stylets are on the outside and the
maxillary stylets are on the inside. Except at
their bases, the maxillary stylets are in-
terlocked by a system of ridges and grooves.
On the inner surface of each maxillary stylet
there are two wide concavities which together
form the food and the salivary canals. The food
canal is anterior to and only slightly larger than
the salivary canal. The bug injects saliva into
the milkweed seed by way of the salivary canal
and sucks the food material into the gut by way
of the food canal.

More specific morphological details are as
follows:

The maxillary stylets are only slightly
longer (5%) than the mandibular stylets. The
length of the stylets, including the base is
about 6 mm. The tip of each mandibular stylet
has a series of transverse, barb-like teeth across
its outer face. A cross section of the whole
stylet bundle, about midway in the shafts (Fig.
1) shows the interlocked maxillary stylets with
the food and salivary canals between their ap-
posed inner surfaces. The stylet bundle is ap-
proximately 26 micrometers in diameter, the
food canal 9 micrometers in diameter and the
salivary canal 8 micrometers in diameter. The
salivary canal is thus only slightly smaller than
the food canal. The mechanism that interlocks
the maxillary stylets consists of three grooves in
the right maxillary stylet and two grooves and
three flanged ridges in the left. The maxillary
stylets are not bilaterally symmetrical. There is
a ridge with two flanges at the anterior margin
of the outer surface of each maxillary stylet
which fits into a groove on the inner surface of
each mandibular stylet. This produces a com-
pactly interlocked stylet bundle but the inter-
locking mechanism is such that independent
movement upon one another is possible for each
of the four stylets. The body of each maxillary
stylet also contains a narrow central cavity
which often appears in sections as two cavities
because of the apposition of parts of its walls.

Each mandibular stylet contains a central
duct running from the base to near the tip. The

30 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976

<<

half of the shafts. CC, cental cavity; CD, central duct; FdC, food canal;
MdS, mandibular stylet; MxS, maxillary stylet; SC, salivary canal.

Fig. 2 Electron micrograph of a section of the central duct in a mandibular stylet of O. fasciatus.
There are six dendrites in the central duct. k:ach dendrite (D) contains neurotubules (NT) and is
suirounded by a cuticular sheath (CS).

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976 Sul

fasciatus. 3. midway, about three mm from the tip, showing five dendrites in the duct 4. about
two mm from the tip, showing four dendrites in the duct and one (arrow) in the wall of the
stylet. 5. at the stylet tip, after the central duct has bifurcated. The two
branches of the central duct are indicated by arrows.

central duct is approximately 2 by 6 micrometers
and contains six dendrites. All the dendrites
were traced from the base of the mandibular sty-
let to midway along the stylet:bundle.' The den-
drites are of two types: three large dendrites
which are usually near the centre of the duct
and away from the walls; and three smaller
dendrites usually placed peripherally and close
to the wall (Fig. 2). About midway along the
stylet bundle one of the small, peripheral den-
drites leaves the central duct and proceeds to
the outside of the stylet and a receptor site,
leaving five dendrites in the central duct (Fig.
3). About 1 mm closer to the tip, another of the
small, peripheral dendrites leaves the duct (Fig.
4), leaving only 4 dendrites in the duct (Fig. 4).
The last small peripheral dendrite leaves the
duct. about 1 mm further distad, leaving only
the three large dendrites in the duct. Close to
the tip of the stylet, the central duct bifurcates
(Fig. 5); one branch contains two dendrites, the
other branch contains one.

The stylets of the large milkweed bug differ
in some respects from those of the Hemiptera
(Suborder Homoptera) previously studied by
me (Forbes 1969 & 1972, Forbes & Mullick
1970, Forbes & Raine 1973, Chan & Forbes
1975). The salivary canal of the large milkweed
bug is almost as large as the food canal,
presumably because large amounts of saliva are
needed to soften the somewhat dry food before
it can be sucked up the food canal; aphids, the
six-spotted leafhopper, the greenhouse

whitefly, the pear psylla, and the balsam woolly
aphid all have a salivary canal which is much
smaller than the food canal. These all suck
liquid plant sap, so that presumably less saliva
is required when they feed. The body of each
maxillary stylet of the large milkweed bug con-
tains a large, narrow central cavity, which is
apparently empty; the maxillary stylets of the
six-spotted leafhopper also have cavities but
these contain dendrites. There are ridges and
grooves that interlock the maxillary with the
mandibular stylets of the large milkweed bug;
no such interlocking mechanism occurs in any
of the homopterous insects mentioned. The cen-
tral duct in the mandibular stylets of the large
milkweed bug contain six dentrites, three of
which are smaller and go to receptor sites
proximad to the tip of the stylet and three of
which are larger and reach the stylet tip; all of
more than 25 species of aphids examined have
mandibular stylets with two similar dendrites
running to their tips (Forbes 1969 & un-
published, Chan & Forbes 1975). The
greenhouse whitefly and the pear psylla also
have two dentrites running to the stylet tips
but the balsam woolly aphid has three. The six-
spotted leafhopper’s mandubular stylets have
three dendrites which run to their tips or very
close to them.

The structure and function of the stylets of
other Hemiptera and the probable significance
of the nerves in the stylets have been discussed
in my earlier papers already cited.

29 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), Dec. 31, 1976

ACKNOWLEDGEMENTS Chan and Miss Bea Schroeder provided tech-
Dr. G. G. E. Scudder, Department of nical assistance and Mr. S. W. MacDiarmid
Zoology, University of British Columbia, sup- Prepared the figures for publication.
plied the large milkweed bugs. Mr. Cho-Kai

References
Chan, C-K, and A. R. Forbes. 1975. Life-cycle of a spiral gall aphid, Pemphigus spirothecae
(Homoptera: Aphididae) on poplar in British Columbia. J. Ent. Soc. Brit. Columbia.
72: 26-30.
Feir, D. 1974, Oncopeltus fasciatus: a research animal. Ann., Rev. Ent. 19:81-96.
Forbes, A. R. 1969. The stylets of the green peach aphid, Myzus persicae (Homoptera: Aphididae).
Can. Ent. 101:31-41.
. 1972. Innervation of the stylets of the pear psylla, Psylla pyricola (Homoptera:
Psyllidae), and the greenhouse whitefly, Trialeurodes vaporariorum (Homoptera: Aleyro-
didae). J. Ent. Soc. Brit. Columbia. 69:27-30.
Forbes, A. R., and D. B. Mullick. 1970. The stylets of the balsam woolly aphid, Adelges piceae
(Homoptera: Adelgidae). Can. Ent. 102:1074-1082.
Forbes, A. R., and J. Raine. 1973. The stylets of the six-spotted leafhopper, Macrosteles fascifrons
(Homoptera: Cicadellidae). Can. Ent. 105:559-567.

Luft, J. H. 1961. Improvements in epoxy resin embedding methods. J. Biophys. Biochem. Cytol.
9:409-414.

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976

COCCINELLIDS AND APHIDS:

A Quantitative Study of the Impact of Adult Ladybirds
(Coleoptera: Coccinellidae) preying on Field Populations
of Pea Aphids (Homoptera: Aphididae)

B. D. FRAZER

Agriculture Canada Research Station, 6660 N.W. Marine Drive,
Vancouver, B.C. Canada, V6T 1X2

N. GILBERT

Institute of Animal Ecology, University of
British Columbia, Vancouver, V6T 1W5

ABSTRACT

This paper examines the quantitative effect of predation by a ladybird
beetle, Coccinella trifasciata, on field populations of pea aphid, Acyrthosiphon
pisum. Field studies showed that no mathematical function, involving only
the current densities of predator and prey, can predict the true predation
rate. We studied the components of the predation process in detail, first
in the laboratory, and then in the field. We derived a new, empirical (not
theoretical) formula for predation rate, which includes predator and prey
densities, predator voracity, prey age-distribution, and temperature.
Temperature has a single effect on the rate of aphid development, but a
double effect on the predation rate, so that coccinellids are much more
effective predators at high temperatures, than at low. Field cage experi-
ments, with known numbers of beetles, revealed that all current methods
of counting adult coccinellids in the field greatly underestimate their true
numbers. When this fault is rectified, the new formula correctly predicts the
predation rate.

The study shows that it is possible to investigate a predator-prey.
relationship, in the field, in considerable detail, in order to predict the preda-
tion rate over a wide range of circumstances. The study reveals several
sharp, qualitative, differences between the predation relationship observed
in the laboratory, and the same relationship observed in the field. All
laboratory studies must therefore be suspect, until verified in the field. In
particular, arthropod predation studies must allow for effects of
temperature on both predation rate and prey population dynamics. The
coccinellid-aphid relationship permits no equilibrium, or steady state, so
that conventional definitions of stability do not apply. The coccinellid’s
functional response is inherently unstable: the relationship is stabilized
solely by a numerical response. Implications for biological control are
discussed.

Contents

1. Background
Sampling and field biology
Biological parameters
Population model

2. Predation in the laboratory
Method
Analysis

3. Predation in the field
Method
Analysis

4. Beetles and aphids combined —first attempt
Sampling and field biology
Effect of temperature on beetles
Synthesis

5. Beetles and aphids combined— second

attempt

Analysis of cage experiments
Discussion

33

34 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), Drc. 31, 1976

6. Conclusions

Laboratory v. field studies

Stability

Some technical considerations

References
7. Acknowledgments

Appendix 1. Aphid population model

Appendix 2. Algorithm to compute physiologi-
cal time in the field

Appendix 3. Field predation model

Appendix 4. Derivation of the expression for
survival rate

Appendix 5. Algorithm to compute weighted
average temperature for beetle

activity

Appendix 6. Aphid population model

Introduction

Morris et al. (1963) pioneered the use of life
tables for insects which have more or less dis-
crete generations. Hughes (1963) and Hughes
and Gilbert (1968) produced a ‘variable life-
table’ model of the cabbage aphid, which has
overlapping generations. That model assessed
the impact of a parasite on the aphid (Gilbert
and Hughes 1971). The parasite had no serious
effect on aphid abundance, which is restricted
by competition and crowding. In_ similar
analyses of other insects (Hassell 1969,
Gutierrez et al. 1971, 1974a, b; Wratten 1973,
Gilbert and Gutierrez 1973), natural enemies
also had scant effect on prey numbers. Yet
many parasites and predators effectively
reduce the numbers of their prey (e.g. Frazer
and van den Bosch 1973, DeBach 1974).

In 1972 we began to study field popula-
tions of pea aphid, Acyrthosiphon pisum
(Harris) on alfalfa, Medicago sativa L. After
the first year it was obvious (§1) that coc-
cinellid predators significantly affect aphid
density in the field. This paper analyses the
predation process (§§ 4 & 5). This is the first
time that Holling’s (1964) ‘‘component
analysis”’ has been applied to predation in the
field, and tied into the life table approach of
Morris et al (1963).

1. BACKGROUND

This section describes the field biology, and
proves that the predation rate cannot be a
function of current predator and prey densities
alone.

Sampling and Field Biology

Alfalfa, Medicago sativa L., cv. Alfa was
sown in 1971 at the University of British
Columbia. The plot consisted of 18 rows each
25 m long and 1 m apart. The crop was cut
three times during the summer of 1972, when-
ever about 10% of the plants were in flower.
This approximated the commercial practice
in the region.

A population of pea aphids, Acyrthosiphon
pisum (Harris), became established on plants

in 1971, overwintered as eggs, and reappeared
in 1972. Pea aphids normally infest the actively
growing terminals of alfalfa. We began sampl-
ing aphids in April and took samples about
once weekly throughout the summer. A sample
comprised 20 plastic bags, each containing ten
terminals collected directly in the field. Pea
aphids readily drop off a plant when it is cut,
but care was taken to ensure that no aphids
were lost. The bags were taken to the labora-
tory, where the aphids were beaten off the
plants onto a sheet of paper, sorted under the
microscope into four juvenile instars and
adults, and counted. The fourth instar and
adult aphids were separated into winged and
wingless morphs.

Hymenopterous parasites, Aphidius ervi
ervi Haliday, A. smithi Sharma & Subba Rao,
and Praon pequodorum Viereck, attack the
aphids. The parasites are themselves attacked
by the hyperparasites Asaphes_ vulgaris
Walker, A. californicus Girault, and Dendro-
cernus near niger Howard. To estimate the
parasitization rate we dissected all aphids of
the third and later instars in every sample, and
recorded the numbers and sizes of parasite
larvae they contained.

Large numbers of adult coccinellids invaded
the alfalfa plot between May 9 and July 18.
The commonest species were Coccinella tri-
fasciata perplexa Mulsant, C. t. subversa
Leconte, C. undecimpunctata undecimpunctata

“L., C. johnsoni Casey, C. californica Manner-

heim, and Cycloneda munda Say. To sample
for coccinellids, observers walked on either side
of each row of alfalfa counting all visible
beetles. At the same time we counted the para-
site mummies. Aphidiid parasites pupate in-
side or below the dead, eviscerated host aphid,
which is transformed into a shell, or ‘‘“mummy’”’.
This gives a second estimate of the para-
sitization rate.

At the start of the season, aphid numbers
began to increase (Fig. 1, May 9-25). After
the beetles had arrived (May 25-31), the aphid
population declined to a low level, which it

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976 35

180
Oe
iJ
a
=!140
=
=
P|
100
oO
i
(a)
die
<q
=
= (A) COCCINELLIDS
yy 20
iJ
_,40 ; ’
< (B) APHIDS
= e
ag
lJ 3.0
bf
a y APHIDS PER
rf INFESTED
o A TERMINAL >
y 2.0 : rs
2 / <
xr P =
<q
ee
: :
z 1.0
= §
Lad APHIDS PER
= TERMINAL

20 40 60 80 120
PHYSIOLOGICAL TIME (QUIPS)

RS aaa) RPE) OE aaa ay TT

MAY JUNE JULY

FIGURE 1A. Coccinellids of all species in the whole plot; 1B, aphids per terminal, both in 1972.
Each aphid sample contained at least 160 plants. The fall in ‘aphids per infested terminal’
beginning at q 84 is probably due to an inaccurate estimate of: p (see text). Curves
A and B (1B) are computed by Appendix 1 in the absence and presence of coccinellids.

36 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), Dec. 31, 1976

maintained throughout the period of maximal
coccinellid numbers (May 31-June 21). There-
after, coccinellid numbers fell sharply, and the
aphids again increased (June 21-July 18) until
the alfalfa was cut. We shall concentrate on
the early period shown in Fig. 1. Later in the
season, the aphids were attacked by many
other natural enemies of aphids, eg. Chryso-
pids, Nabids, Mirids, Spiders, Syrphids, and
Coccinellid larvae. At the same time, the alfalfa
plants grew so big that the aphid samples be-
came unreliable.Nevertheless, the aphid popu-
lation dynamics during the first half of the
season are sufficiently simple to permit some
understanding of the underlying processes.
Our task is to explain the course of aphid num-
bers shown in Fig. 1.

Biological parameters

An aphid goes through four instars before
becoming adult. We estimated the duration of
each instar, and the pattern of adult fecundity,
by rearing aphids in the laboratory at each of
four constant temperatures (10°, 15°, 20°, 25°).
The development rate increased linearly with
temperature in this range, so that a given in-
star required a constant amount of ‘physio-
logical time’, measured in day-degrees above a
threshold temperature of 4°C (Campbell et al.
1974). Since this physiological time-scale is
the aphid’s own time-scale, we adopted it for
this study. The first three instars each took
about the same amount of physiological time,
which we adopted as the aphid’s basic time-
unit, one ‘instar-period’. The fourth instar
took longer; 1% instar-periods for wingless
aphids, and 1% for winged. To accommodate
these varying periods, we adopted one quarter-
instar-period, or ‘quip’ (q), as the unit of
physiological time. For the pea aphid at
Vancouver, one quip equals 6.56 day-degrees C
above the threshold temperature of 4°C.

Parthenogenetic wingless aphids mature
after 18 q, begin to reproduce at 19 q and can
survive to 90 q. The physiological time-scale
compensates for the effects of temperature,
not only on development, but also on re-
production. For reproduction, the compensa-
tion is not quite perfect, but on the physiologi-
cal time-scale, the time pattern of reproduction
was nearly the same for the four temperatures.
In other words, on this scale, both the total
fecundity and the reproductive pattern are
effectively independent of temperature.

Population Model

These development times and fecundities
allowed us to predict the rate of aphid increase,
assuming that all individuals survive to age
90 q. This we did by a simple simulation model
(Appendix 1). We first converted calendar
time in the field to physiological time, using a
computer program (Appendix 2) which fitted
sine curves to daily maximum and minimum

air temperatures, and integrated them above
the developmental temperature threshold
(Morris & Bennett 1967). Each day in the field
calendar was converted to its equivalent in
physiological time, beginning arbitrarily on
May 1, 1972.

There was a large discrepancy between the
aphid model (curve A, Fig. 1) and observed
aphid densities. The data indicated heavy
mortality while the coccinellids were present.
The age distributions (not shown) agreed.
From 0-22 q, the aphids increased in numbers
(fig. 1) at the rate predicted by the simulation
model. No beetles were seen until 20 q. During
20-40 q, there was an influx of beetles, and the
aphid population began to decline. The beetles
remained in large numbers during 40-70 q,
and the aphid population remained low. Most
of the beetles left the plot between 70-120 q,
whereupon the aphid population resumed its
exponential increase.

The beetles had some direct effect on the
aphids, as indicated by changes in the average
number of aphids per infested terminal. The
probability p that a sample unit of n terminals
contains no aphids is f™ where f is the frequency
of uninfested terminals. From the values of p ob-
served in the samples we estimate the corres-
ponding f and p!,, . The average number of
aphids per terminal is then divided by (1-f), to
estimate the average number of aphids per
infested terminal. During the period May 9-19
(9-22 q, Fig. 1), that number increased from 1.9
to 4.2, since the population consisted of adults
and their progeny, living on the same plants.
The frequency f of unoccupied terminals was
considerably greater than would be predicted by
a random, i.e. Poisson, distribution with the ob-
served mean number of aphids per terminal.
When the beetles arrived during 20-40 q, the
average number of aphids per infested terminal
fell to its minimum level of one, a probable result
of the activity of the beetles. When beetles
search plants, they catch only a small propor-
tion of the aphids and scatter the rest on the
plants. When the beetles left, the aphids became
aggregated again as the mean density increased.

At first the simulation model used the
simplest possible predation function. The
beetle’s voracity was measured by feeding
average-sized aphids to adult C. trifasciata in
the laboratory. It was recorded as a number of
aphids; later, we used biomass. If there are 6
beetles per terminal, and each eats k aphids per
q, the demand for aphids will be kb per q. If
there are a aphids per terminal, each aphid
must expect to be eaten kb/a times per q. If
the beetles search at random, the aphids will
escape predation with a frequency equal to the
zero term of the Poisson distribution, which in
this case equals exp (-kb/a), a crude expression
that worked well in previous cases (Hughes &

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976 3d

Gilbert 1968, Gilbert & Gutierrez 1973). When
this survival rate, calculated in the model for
every q, was applied in the population model,
the aphid numbers rapidly decreased to zero

(curve B, Fig. 1). But the field counts of beetles

probably underestimated the true numbers,

since some beetles escape notice. We therefore
concluded that:

(1) The beetles were sufficient in timing and
numbers, to explain the early season re-
duction in the aphid population.

(2) The success of the beetles in finding aphids
at low density was considerably less than
that predicted by random search.

(3) No. conceivable mathematical function
which includes only the current average
numbers of predators and prey, can predict
the survival rate of the prey: aphid and
beetle numbers were much the same at 30 q
and 90 q, yet at 30 q aphid numbers de-
clined, and at 90 q they increased (Fig. 1).
The true predation rate must therefore be
affected by some other factor, which might
be some characteristic of the predator or
prey populations, e.g. age distribution or
aggregation (cf Hassell & May 1973), or
some environmental factor. We decided to
study the predation process in detail.

2. PREDATION IN THE LABORATORY

Holling (1966) has shown how to study the
actual process of predation with great realism.
Rather than invoke theoretical functions and
assumptions, Holling studied the detailed be-
haviour of the predators and prey, to determine
the important biological parameters which pre-
dict the ‘functional response’. But his approach
is too complex for application in the field. We
needed a simpler model of predation, at once
realistic but simple enough for field use. We
decided to study predation in an artificial
arena to identify those essential components
which must unavoidably be measured in the
field. To avoid duplication of symbols, we shall
freely mix algebraic and FORTRAN notations.

Methods

The tests were made in standard greenhouse
flats each containing 12 small alfalfa plants
arranged in a 3 x 4 grid. Each plant had a single
stem with many of its leaves removed, so that
the aphids could easily be seen. To make the
aphids visible when on the ground, the soil
was covered with white sand. The sand was kept
wet because the beetles made poor traction on
dry sand. The aphids and beetles were confined
by a transparent plastic cage 29 cm x 45 cm
and 21 cm high. To prevent the insects from
walking up the walls of the cage, its lower rim,
which rested on the sand at the edge of the flat,
was coated with Fluon (a brand of polytetra-
fluoroethylene dispersion supplied by Imperial
Chemical Industries Ltd.). All the coccinellid
species found in the field, except one, readily

flew off the plants and landed on the cage, so
nullifying the test. The exception was C.u.
undecimpunctata, which we adopted for the
laboratory work.

We re-defined ‘hunger’ as that weight of
aphids which a beetle will voluntarily eat until
satiated. We established the hunger curve
by feeding forty beetles until they refused to
eat aphids presented directly to them, then
starving them for various time periods at
24 + 1°C, and weighing them. Each was again
fed to repletion, and its increase in weight re-
corded. After 24 hours’ starvation, males of
C. u. undecimpunctata will eat a maximum of
2.0 mg. of aphid on average, and females about
3.0 mg. We therefore write HGR = 2.0xH for
males, and 3.0xH for females. The curve for
H (Fig. 2A) is of the type H = 1 - exp/(-kt)
(Holling 1966). Thus we shall use H for the
relative hunger, the same for both sexes, and
HGR for the absolute hunger.

The laboratory tests were done in a con-
trolled room at 24.0 + 1°. We placed aphids in
known numbers and instars on the 12 plants,
and left them to settle. Then we chose a beetle
of known sex, which had been starved for a
predetermined time at constant temperature,
so that its initial hunger HGR could be esti-
mated (Fig. 2A). Dixon (1959) has shown that a
coccinellid changes its search pattern when it
makes contact with an aphid, even if it does
not capture the aphid. Therefore, each time the
beetle climbed onto a plant, we recorded its
hunger HGR and the time TLC since the beetle
last contacted an aphid. At the start of each
test we allowed the beetle to make contact with
an aphid but not to capture it. Both HGR
and TLC were thus established at the start of
each test.

The beetle was placed on the sand inside the
cage, where it began to search the plants for
aphids. For every visit to a plant, we recorded
the following: plant height; the number of
trifoliate leaves; numbers and instars of the
aphids on the plant at the start of the visit;
numbers and instars of aphids which were
eaten, which fell from the plant but returned to
it, and which fell and left the plant for another;
whether or not the beetle made contact with
an aphid on the plant; and the lengths of time
which the beetle spent in searching the plant,
stationary on the plant, moving on the ground
after it had left the plant, and stationary on
the ground.

A beetle is stationary when it is eating,
cleaning its appendages or resting, usually
when it is not hungry. A beetle detects aphids
only when it contacts them with its maxillary
or labial palps. After contacting an aphid, the
beetle scours the locality very thoroughly,
making frequent turning movements. When a
beetle searches a plant, many of the aphids on

38 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DrEc. 31, 1976

S

@ MALE °
Oo FEMALE @

°

wo

y=3(1-e 9 !4T)

Ls)

yo 2tiae 2147)

WEIGHT OF APHIDS EATEN (Mg)

8 12 16
HOURS OF STARVATION

a

@® MALE
Oo FEMALE

y= 3.8(1-e 9-08T)

fw ou >

WEIGHT OF APHIDS EATEN (Mg)

10 60 70

20 30 40 50
HOURS OF STARVATION

FIGURE 2A. Hunger, HGR, curves of Coccinella undecimpunctata at 24°C; B, C. trifasciata at 20°C.
Each point is a mean value from about 40 beetles. The physiology underlying the variability
in hunger has not been explored, but females tend to vary more in weight than males
because captive females may lay eggs, and may or may not eat them.

that plant fall off, and so avoid predation. The
aphids rarely left plants unless disturbed. We
tallied the aphids as they moved from plant to
plant, by means of counters which were moved
correspondingly from square to square of a
checkerboard. In this way, the current popula-
tion of any plant was known whenever a beetle
climbed onto it. A beetle can capture and eat
aphids of all sizes, and the average time taken
to consume an aphid is directly proportional
to the aphid’s weight (Fig. 3). But not all pea
aphids are equally at risk. The older and larger
aphids drop from plants much more readily
than the young ones, so that first and second
instar nymphs are those most vulnerable to
predation. Large aphids which have fallen off
a plant can find their way onto a new plant
much more readily than can small aphids. In
particular, a winged adult is largely immune
from predation, partly because it readily falls
off the plant, and partly because the beetle
usually seizes the aphid by its wings and so

400

a
fe}
°o

200

CONSUMPTION TIME (SECS)
°
°

0.2

0.4 0.6 08
APHID WEIGHT (Mg)

cannot eat it without first letting go, where-
upon the aphid usually escapes.

We made fifty such laboratory tests, each
lasting an hour or more. Altogether, 2,020
plant visits were recorded, with varying num-
bers and distributions of aphids. When two
beetles were placed in the cage together, they
searched independently.

Analysis

The next step is to determine, from the data
collected in the laboratory tests, the ‘com-
ponents’ of the predation process (Holling
1966). The measurements taken were very
variable, but regression analysis revealed the
following relationships, which were similar for
both sexes. The probability, PC (Table 1) that
a beetle would make contact with an aphid on
a given plant was proportional to the beetles’
hunger, HGR, and to the number of aphids on
the plant. That probability was never very

1.0 1.2 1.4

FIGURE 3. Times taken by adult C. undecimpunctata to eat various instars of aphid at 24°C. Each
point is a mean of between 9 (adult) and 70 (1st instar) aphids.

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976 39

TABLE 1. Variable Names and Their Meaning
AWT—weight (mg) of one aphid; which varies with instar (Table 2).

HGR—hunger (mg) of aphid (Fig. 2).

H—hunger, on a relative scale from 0 (replete) to 1 (fully hungry).
PC—probability that a beetle will make contact with an aphid.
PE—probability that a beetle will eat an aphid.

PL—probability that an aphid will leave a plant.

TLC—time (sec) since a beetle last contacted or ate an aphid.

TS—time (sec) spent searching a plant.

great. If no contact was made, the time, TS,
which the beetle spent on the plant, increased
with plant size and decreased with TLC, the
time since last contact. According to the re-
gression analyses, ‘plant size’ is best expressed
as the simple product of plant height and the
number of leaves. The probability, PL, that any
given aphid shall leave a plant increases with
TS. If contact was made, the probability, PE,
that the beetle ate any given aphid was propor-
tional to HGR. Since older aphids fell off and
escaped predation more easily than younger
ones, the probabilities PL and PE had to be
corrected by factors appropriate to the
different aphid instars (Table 2) present on the
plant.

When no aphids were eaten, TS increased
with plant size: when some were eaten, TS in-
creased with the total number of aphids on the
plant, and additional time elapsed while the
beetle ate its prey and cleaned its mouth parts.
Time spent in eating was proportinal to the bio-
mass of the aphid eaten (Fig. 3). Whether or
not any aphid was contacted, PL increased
with TS: but PL (with contact) exceeded PL
(no contact), because the beetle searched the
plant more thoroughly after it had made con-
tact. The beetle also spent time on the ground,
while moving between plants. If the beetle was
hungry (HGR was large) or if it had recently
contacted an aphid (TLC was small), it spent
a relatively short time on the ground.

These relationships were built into a simula-
tion model of the predation process. Since the
relationships are all linear, the model uses aver-
age values; for example, TS is actually very
variable, even allowing for plant size, etc., but
the model uses the average value appropriate
to the particular circumstances. Since the
model represents events in the laboratory only,
we shall not describe it in detail: but later we
shall present a similar, but simpler, model of
predation in the field (Appendix 3). The labora-
tory model was checked, and the values of PE
and TS were altered in order to reproduce the
timing and frequencies of eating and leaving
observed in all the various experimental con-
ditions.

We then analysed the laboratory model to
see which features could safely be omitted—
especially those difficult to measure in the field.
The most important conclusion was_ that
although contact certainly influenced the be-
haviour of individual beetles, its effect could
be absorbed into the values of PE and PL,
and so the whole mechanism of contact could
be omitted, provided the PE and PL were modi-
fied appropriately. This was fortunate, since it
would be almost impossible to observe TLC in
the field. However, the contact mechanism
might cause PE to increase with the number of
aphids on the plant. But an analysis of the
numbers of aphids eaten on plants with varying
initial numbers of aphids, showed no tendency

TABLE 2. Values of AWT, FACTE and FACTL
Average weights (mg) of aphids in the field (AWT) in 1973 and 1974. Aphids in the laboratory
were generally lighter (cf. Appendix 3). When a beetle visits a plant, each aphid on that plant is
eaten or leaves the plant, with relative frequencies FACTE and FACTL respectively. The fre-
quencies were estimated during the laboratory tests. They must be multiplied by appropriate

constants to give absolute frequencies PE or PL.

Aphid

Instar 1

Instar 2

Instar 3
Instar 4

Adult wingless
Adult winged
Mummy

AWT FACTE FACTL
0.17 1.68 0.64
0.33 1.28 0.68
0.91 0.75 1.05
1.88 0.52 1.13
3.82 0.46 1.29
2.15 0.36 lots IF
1.88 0.57 —

40 J. ENTOMOL. Soc. BrIT. COLUMBIA 73 (1976), DEc. 31, 1976

for PE to vary; except that once one aphid had
been eaten, other aphids on the same plant
were slightly more likely to be eaten. The effect
could be ignored, leaving hunger as the sole
driving mechanism.

3. PREDATION IN THE FIELD

This section converts the laboratory preda-
tion model to represent the same process in the
field, and uses it to predict the survival rate of
aphids in the field. As far as possible, we
measured all the model’s parameters again, by
watching and timing beetles in the field.

Timing

In the first series of field observations,
we watched beetles searching at a low aphid
density of about 0.2 per terminal. One observer
followed the beetle’s progress over the vegeta-
tion, while another timed and recorded each
visit to a new plant. In this way, we estimated
the average time, TS, which a beetle spends on
a plant when no aphid is eaten. The estimate of
TS, i.e. 51.3 sec (Appendix 3), is the average
of 504 plant visits.

It was not necessary to measure the sizes
of the alfalfa plants in the field. They were
generally larger than those in the laboratory,
with more leaves and branches. But the beetles
did not search the entire plant; instead, they
primarily searched the sunlit canopy of con-
tiguous leaves and stems, where most of the
aphids were. Most importantly, neighbouring
plants touch, and so both aphids and beetles
walked or flew freely from plant to plant. The
beetles spent no time on the ground while
searching for aphids, and the time spent on
any plant did not depend on that plant’s overall
size.

Probability of Capture

In another series of field observations, we
seeded lengths of row with high densities of
aphids, and watched the beetles search for
them. The average density of aphids on these
plants was determined afterwards by sampling.
That density, multiplied by the total number
of plants visited (286), gave the total number
of aphids at risk, 1746. Of those, 32 were
actually eaten, giving a frequency PE of
capture of 0.018. In the model, PE equals a
constant times the relative hunger H. This
constant is tentatively deduced as follows:
since the beetles flew in from other parts of the
field where aphids were scarce, we assumed
that the beetles were very hungry, with
H=0.88, corresponding to 15 h starvation as
set initially in the model (Appendix 3). The
constant must therefore be 0.018+0.88, so that
PE=0.0205 x H. This equation is re-examined
in Appendix 4. The value of PE is much lower
in the field than in the laboratory, because in
the field a beetle makes only a cursory search
of each plant, but searches many more plants in

a given time. The same series of field observa-
tions gave the average time spent on one plant
when aphids were eaten. In the laboratory
model, PE was a function of time searching,
which in turn was a function of plant size. In
the field model, PE is no longer affected by
plant size, and therefore the distinction
between time searching and not searching is
no longer required. Regression analysis of the
field data shows that the time spent on a plant
increases with the number of aphids eaten;
so in the model, it appears as a linear function
of the total weight of aphids eaten (Fig. 3).

Probability of prey movement

We could not directly measure PL, the prob-
ability of an aphid leaving a plant, because
it was impossible to see how many aphids
left during a visit by a beetle. However, PL
must depend on the beetles’ searching be-
haviour in much the same way as PE. There-
fore, to estimate PL in the field, we took the
frequency with which aphids fell off the plants
in the laboratory, and changed it in the same
proportion as the observed change in PE. The
resulting value of PL must clearly be suspect;
fortunately, analysis of the model showed that
within reasonable limits, the value of PL had
little effect on the predation rate. This does
not, of course, imply that the aphids’ be-
haviour in leaving the plant did not affect the
predation rate, for that behaviour affected PE
as well as PL. Having thus obtained overall
values for PE and PL, we used the same factors
(Table 2) as were observed in the laboratory,
to compute the probabilities for each aphid in-
star. This was unavoidable, since it was im-
possible to count all the aphids of each instar
on a plant in the field without disturbing them.
However, these corrections were reasonable,
because the relative frequencies depended
more on the behaviour of the aphids than of
the beetles. Most of the aphids captured by
beetles in the field, were the youngest, as in
the laboratory.

We now use these rules to develop the field
model for predation (Appendix 3). It is im-
possible to determine the sex of each beetle
encountered in the field without unduly distur-
bing it, and so the field model assumes a 1:1
sex ratio.

Effects of Temperature

The model describes events during one q at
18.5°C, the average temperature during the
field observations. But the times spent on each
plant are related to the speed at which beetles
move and thus to temperature. We placed
beetles of the three species on vertical poles
in the laboratory, and timed their walking
speeds at different temperatures. The result
(Fig. 4) shows that the beetles’ walking and
searching speed has about the same temper-

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976 4]

ature threshold as the aphids’ rate of develop-
ment, and so we may use the same physiolo-
gical time-scale for both predators and prey.
The field predation model therefore describes
the predation process during one q at any
ambient temperature.

Temperature has an additional effect on
coccinellids. At low temperatures, many of
the field beetles are inactive (Fig. 7), even
though they are capable of motion (Fig. 4).
The physiological time-scale thus allows for the
effect of temperature on the beetles’ speed of
search when active, but not for the variable
amount of activity. Therefore, the number of
beetles actually present at any given time
must be multiplied by an activity coefficient,
to give the effective number of active beetles.
At first, we used the data in Fig. 7 to estimate
the activity/temperature relation, with a tem-
perature threshold of 8.7°C. But later we found
(§ 5) that the counts in Fig. 7 are still biassed.
The field cage experiments in § 5 demand that
the temperature threshold be reduced to 4°C,
the same value as for beetle movement. The
algorithm used to calculate the approximate
average temperature, for each q in the field,
appears in appendix 5. Despite several
attempts, we have not obtained a direct estim-
ate of the activity/temperature relation, which
is complicated by effects of sunshine and by
some kind of circadian rhythm. But the fact
that temperature has a double effect on the
beetles, and a single effect on the aphids, has
important consequences for the predator-prey
relationship (§ 6).

3.0

(A) C trifasciata

2.0

fo)

RATE OF TRAVEL (CM/SEC)
° fo)

°

10 15
TEMPERATURE (C°)

C. californica

Analysis

The aphid survival rates, predicted by the
field predation model, will now be applied to
the aphid population model. It would be
possible to build the predation simulation
model directly into the aphid population model,
by calculating the survival rate de novo when-
ever it is needed. To do so would take im-
practicable amounts of computer time. The
results of the predation model are best ex-
pressed as empirical functions which can be
used directly in the population model.

The predation rate must depend on beetle
density, and on aphid age-distribution, den-
sity and possibly aggregation. All these para-
meters must therefore appear in the empirical
function. The problem is not really so complex.
For the model shows that the overall survival
of a mixture of aphids of different ages is
about equal to the weighted average of the
predicted survival rates of the individual age
groups. For example, it shows that the survival
of 0.2 adult + 0.6 instar I aphids/plant (total
density = 0.8) is, very nearly, % of the survival
of 0.8 adults/plant + % the survival of 0.8
first instar/plant. Moreover, the survival rate
must. be squared when the beetle density is
doubled, since the beetles search independently
of each other. The model shows just that effect,
which incidentally proves that the model’s
time-step of one q is short enough, as far as the
beetles are concerned: that is, within one gq,
no beetle can destroy so many aphids that it
seriously reduces the number of prey available

y=-0.17 +0.043X

y=-0.25 +0.049x

20 25

FIGURE 4. Effect of temperature on coccinellid walking speeds. Each point is a mean of
about 40 observations.

42 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DrEc. 31, 1976

APHID DENSITY
4 6

0.954

{eo}
o
°o

APHID SURVIVAL RATE
o Oo
© @
9 a

°
af
a

0.707

FIGURE 5. Survival rates per q, computed by Appendix 3, of second-instar aphids attacked by
C. trifasciata. Coccinellid density=1/60 plants. Curves A, B, C are fitted in Appendix 4.

to other beetles. These circumstances permit
us to analyse the predation model, using beetles
at a fixed density, and aphids of one instar
only. We used second instar aphids, and beetles
at the highest density observed in the field,
viz. 1 per 60 plants. We chose this case because
it gives high aphid mortality, and therefore
accurate estimates of survival rates. For each
aphid density, the model (Appendix 3) was
run many times, using different random num-
bers: the average survival rates predicted for
varying aphid densities are shown in Fig. 5.
They do not lie precisely on a smooth curve
because they are estimated by this ‘Monte
Carlo’ method, which estimates the survival
rate from a finite number of trials.

The effects of aphid distribution or aggre-
gation on predation rate are slight according to
the field predation model. At average densities

PREDATION RATE /HOUR
,o) ro) (
oO “

ro)
o

Ol

2 3
APHID DENSITY

of less than one per plant, the survival rate is
slightly lower when the aphids are highly
aggregated on few plants, than when well
spread out on isolated plants. That is because,
having found one aphid, a beetle easily finds
the others on the same plant. There is no such
effect at high aphid densities, when a beetle can
find enough aphids irrespective of their distri-
bution.

By contrast, the laboratory predation model
showed a great effect of aphid distribution
(Fig. 6): the predation rate might be three
times greater when the aphids were clumped,
than when they were well spread out. This was
an effect of timing, which persisted after the
contact mechanism was eliminated from the
model. It arose because, in the laboratory, the
beetles could not climb directly from one plant
onto another, and therefore spent a long time

FIGURE 6. Predation rates per beetle-hour at 24°C, computed by the laboratory predation model,
of second instar aphids when attacked by C. undecimpunctata. Coccinellid density = 1/100
plants. Different lines refer to different initial proportions of uninfested plants, as marked.

J. ENTOMOL. Soc. Brit. COLUMBIA 73 (1976), DEc. 31, 1976 43

on each plant. In the field, however, the beetles
moved directly from plant to plant, and thus
visited many more plants for each aphid
caught.

A predator-prey relationship might indeed
be stabilized by predators scattering their prey
(cf. Huffaker, Shea & Herman 1963), but not in
our alfalfa plot, where the predators ranged
freely and quickly over the area. We therefore
ignored the slight effect of aphid distribution
found in the field predation model, because it
was equivalent at most to a 5% increase in
beetle density, which is well within the ac-
curacy of our field counts.

The next task was to fit an empirical func-
tion for survival from predation. We already
knew how to deal with varying beetle densities
and mixtures of aphid instars, so we needed
only to fit a curve to the predicted points in
Fig. 5. This was done (Appendix 4) and the
resultant expression for the survival rate of
aphids of instar I is

s=exp (Saar = pee (1 - ex (-ka)) )

= AWT(I)~ a pat
where k=2.6 x AWT (I) x FACTE (I) x (0.654 +
0.026/a+0.075)). This expression for s gives
the fitted curve C in Fig. 5. By contrast, curve
A is the random search curve, discarded in§1.

During the period 1 - 121 q of 1972 (Fig. 1),
field densities of aphids were always less than
one per plant. At these densities, the survival
rate predicted by the model is very much higher
than the random rate (Fig. 5), for the following
reason: random search implies that the beetles
can find aphids immediately, whereas the model
imposes a time restriction. At low aphid den-
sities, there is far too little time within a single
q for a beetle to visit enough plants to find all
the aphids it needs. Little wonder that random
search in § 1 incorrectly predicted the demise of
the aphid population.

4. BEETLES AND APHIDS COMBINED
—FIRST ATTEMPT—

This section tries to reconcile the predicted
predation rate with the observed survival rate
of aphids in the field. By the time we had com-
pleted the field predation model, we had ob-
tained population records from a new season
which showed that the 1972 beetle counts were
inaccurate. We therefore shall not use the 1972
data further, but instead describe the field
methods used in 1973.

Sampling and field biology

Two plots of Alfa alfalfa were sampled
0.8 km apart on the grounds of the University of
British Columbia. Plot 1 was that sampled in

1972. Plot 2, sown in 1972, consisted of 26 rows’

each 15 m long and 1 m apart. When the alfalfa
was cut infrequently, the plants produced
numerous lateral branches which made our
sampling units of plant terminals ambiguous
and ill-defined. We therefore departed from

standard commercial practice in 1973 by cut-
ting more often, whenever the plants reached
about 1 m in height. All the rows were cut
simultaneously on plot 1, but even- and odd-
numbered rows of plot 2 were cut alternately,
so that half the rows always contained tall plan-
ts bearing aphids. We sampled the even and
odd rows of plot 2 separately, whereas plot 1
was sampled as a unit. Aphid samples were
taken by cutting individual plant terminals and
beating aphids off. The small-scale distribution
of aphids over the plants does not seriously af-
fect the predation rate in the field (§ 3). We
looked for consistent large-scale patchiness, by
taking samples from a regular grid pattern over
the whole alfalfa plot. There was none. The
number of terminals per sample varied between
40 and 400, according to the aphid density.
Aphid samples were taken from each plot at
least once a week, but 2-3 times a week during
warm periods, when aphids were developing
quickly.

The 1972 method of counting coccinellids
and parasite mummies gave reproducible
results; but we later found it to be inaccurate
because mummies are easily overlooked and
beetles are most easily seen when temperatures
are high. Instead, we randomly chose between
40 and 70 short (30 cm) lengths of row, and
searched them thoroughly for beetles. Beetle
numbers changed rapidly (Fig. 8), and so we
sampled almost daily during the main period of
attack. Each beetle was classified by species,
and according to whether it was moving or
stationary when first sighted (Fig. 7). The am-
bient temperature inside a Stevenson screen
placed on the ground in the plot was also recor-
ded. The same species of coccinellids were
found as in the previous year, but since C. john-
soni was observed freely mating in the field
with C. californica, we counted them as one
species. The dominant species was again C.
trifasciata, which was three to five times as
common as C. californica. The other species
were comparatively rare.

We counted mummies at least twice weekly
by the same method used for beetles. The mum-
mies were classified as unemerged, emerged or
preyed upon. The latter are easily recognized
because the edges of the irregular holes made
by coccinellids or the punctures made by
chrysopids and nabids are darkly stained; the
circular emergence holes of primary parasites
and the irregular emergence holes of hyper-
parasites are not stained. We took samples of
unemerged mummies from time to time and
reared them at constant temperature, to
estimate the sex-ratio of the parasites, their
age-distribution, and rates of hyper-
parasitization.

The numbers of plants per foot of row were
counted at various times through the season, to

44 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), Dec. 31, 1976

0.8

y= -0.39 +0.045 xX

PROPORTION MOVING

12 16 20
TEMPERATURE (C°)

24

FIGURE 7. Effect of ambient temperature on proportion of C. trifasciata observed moving in
field counts. For absolute numbers, see Fig. 10.

reconcile the two methods of sampling, viz.
aphids/terminal, and beetles/length of row. We
made checks by enclosing all the plants in one-
foot lengths of row in plastic bags, cutting the
plants at the base, and counting all the aphids
and mummies found in the bags. Consistently,
the average number of mummies/ft. was about
twice that observed in the regular counts,
mainly because mummies on the underside of
the leaves or low on the plant, had been
overlooked. The regular counts therefore are
multiplied by the appropriate factor to correct
for this under-estimate. Equally consistently,
and irrespective of average plant height, total
numbers of aphids/ft. were only half those
predicted by multiplying the number of plan-
ts/ft. of row by the average number of
aphids/plant derived from aphid samples. This
is not unreasonable, since tall plants are much
more heavily infested than the short ones. We
therefore divided the counts of plants per foot
by the appropriate correction factor to give the
number of effective plants per foot.

Synthesis

Next we insert into the population model
the aphids’ rate of survival from predation,
calculated by the field predation model, and
using the new beetle density b. We make no
distinction between the different species of coc-
cinellids, but equate them all to C. trifasciata,
which was always in the majority.

On plot 2 (1973), a generation of parasites
matured during the period of coccinellid attack
(Fig. 8). The mortality due to parasitism must
therefore be inserted into the aphid population
model. The best estimate comes from the field
counts of mummies, and we therefore include in
the model an amount of parasitization which
reproduces the observed pattern of parasite

mummies, both in time and numbers. We used
the following method: the developmental
threshold for the parasite Aphidius ervi is 4.2°;
thus the two physiological time-scales are in
proportion throughout the period of beetle at-
tack. The length of time spent by a parasite in
the mummy can therefore be equated to a fixed
amount of the aphid’s physiological time,
namely 15 q.

It is the juvenile aphids between ages 4 q
and 17 q which bear the brunt of the parasite
attack (A. Campbell, pers. comm.). Laboratory
tests showed that parasitized aphids, collected
in the field in their fourth instar, can produce
up to 26 progeny before the parasite pupates
and kills the aphid. We therefore represent
parasitism in the following way: parasitized
aphids are not distinguished from unparasitized
aphids in the model until the time comes for the
parasite larvae to pupate. Then a proportion of
aphids in the appropriate age-range is con-
verted into parasite mummies. The correct
proportion of parasitized aphids will thus
produce their appropriate number of progeny
before they die. The proportion of aphids con-
verted into mummies, varies with time. The
proportions were chosen by trial-and-error, to
give the observed numbers and time-pattern of
mummies in the field.

The parasite mummies are themselves sub-
ject to coccinellid attack, and therefore form a
distinct class of prey in the predation model.
The model gives the observed proportion of
preyed-upon mummies, only when the
predation rate on mummies is reduced to one-
third the predation rate of first instar aphids
(Table 2). Unlike healthy aphids, parasitized
aphids often move to the upper surfaces of
leaves, where beetles rarely search. The mum-

J. ENTOMOL. Soc. Brit. COLUMBIA 73 (1976), DEc. 31, 1976 45

15
ay
Wor
- 10
Zao
ae
>a °
<I=m
Ld
a
sii 5.015
q =
waz CUT
= W005
1s eae eee MR Ieee
4
= 25
=
rT
_ 2.0 ---B
a A
7 ,
oO 861.5
w”
a C
= ‘
= 40
<q ;
z
t o5 - RAIN CUT :
= > és 7
ev 130

5O 70 90 110
PHYSIOLOGICAL TIME (QUIPS)
i ee ae eT ae PN Se Le i en eee rape ha a naee

MAY JUNE JULY

FIGURE 8. Numbers of beetles and aphids in 1973, plot 2, even-numbered rows. The upper section
shows the weighted average temperature/q. TEMP, above the activity threshold 8.7°C. It is
computed by Appendix 5 and used in Appendix 6. The middle section shows the field counts,
COCC, of beetles/plant. The temporary increase in beetle numbers during gq 60-q 65 occurred when
the odd-numbered rows of alfalfa were cut, and the beetles moved to the uncut even-numbered
rows. The lower section shows the observed numbers of aphid/plant, together with three curves
computed by Appendix 6. The population model reproduces the effect of heavy rain at q 62 by
imposing the appropriate survival rate on the aphids; similarly when the alfalfa was cut at q 80.
These survival rates were found empirically by comparing aphid densities before and after the
event. Precisely the same survival rates were observed on plot 1 and on the odd-numbered rows of
plot 2.

46 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976

mies therefore suffer an unexpectedly low rate
of predation.

Fig. 8 shows the population dynamics of
aphids and beetles on the even-numbered rows
of plot 2, during and immediately after the
period of beetle attack in May and June, 1978.
The physiological time-scale starts on March 1,
1973. The pattern of events was very similar on
the odd-numbered rows of plot 2, and on plot 1,
i.e., the coccinellids arrived when the aphids
were increasing in numbers, and the aphid
population then declined, the beetles left, and
the aphids again resumed their exponential in-
crease. The same thing had happened in 1972
(Fig. 1).

Aphid numbers never exceeded an average
of 0.7 per terminal during the period shown in
Fig. 8, and so no density-dependent com-
petition for food can be invoked. The
population model simply combines fecundity
rates for the aphids with the predicted survival
rates from coccinellid and parasite attack. To
explain the observed changes in aphid numbers
the model must predict rates of survival from
parasitization and predation, equal to those
which the aphids actually experienced in the
field. The predicted effects of parasitization and
predation are too low to prevent a steady in-
crease in simulated aphid numbers (curve B,
Fig. 8). If the number of beetles is arbitrarily
quadrupled, the model simulates the observed
aphid numbers well enough for the period 15-79
q during the beetle attack (curve C, Fig. 8). We
are out by a factor of four.

The curves in Fig. 8 were computed (Ap-
pendix 6) using the laboratory estimate of
aphid fecundity. Much later we found (§ 5) that
fecundity in the field is consistently only 30% of
the laboratory estimate. This largely explains
why curve C (Fig. 8) rises too fast during the
period 80-130 q, when few coccinellids were
seen. But it does not explain the discrepancy
during the period of beetle attack. Using the
true aphid fecundity, the observed number of
beetles must be doubled, if the population

model is to reproduce the field data. Fig. 9

~ ol

AVERAGE FECUNDITY PER QUIP

20

25 30
TEMPERATURE (C°)

shows the results of laboratory experiments to
test the effect of high temperatures on aphid
fecundity. There was no effect until the tem-
perature exceeded 27°C, which was the highest
temperature observed in the field. Thus the new
population model gives a better approximation
of the true mortality, than the ‘random search’
of § 1; but it now seems to underestimate the
beetles’ destructiveness.

5. BEETLES AND APHIDS COMBINED
—SECOND ATTEMPT—

This section reconciles the predicted
predation rate with the prey population
dynamics.

In 1974, we erected four cages on plot 1.
Each cage was 5 x 6 x 2 m high, and contained
three rows of alfalfa each 6 m long. The cages
were covered with translucent plastic and
screening, which together admitted light, fresh
air and rain. The temperatures recorded in the
cages were sometimes a few degrees higher,
during the day, than those in the field outside.
We used the cages to compare aphid population
dynamics in the presence and absence of known
numbers of coccinellids. These were irst-
generation beetles bred in the laboratory, par-
tly to eliminate parasitism, but mainly because
we could not rely on collecting enough beetles
from the field, early in the season. Figs. 11-13
show the results of three successive ex-
periments, made for different purposes and in
different conditions. The first was to determine
the number of ladybirds needed to make an ob-
vious reduction in aphid numbers, without
driving them down too low. It also examined
the possibility that the aphids might suffer
mortality, over and above the direct predation,
when beetles drive them off the plant; for
example, when the youngest aphids fall off a
plant in the laboratory, they have difficulty in
finding a new plant. This explains why they fall
off so much less readily than the older aphids
(Table 2), even though they suffer a greater
rate of predation in consequence. The weather
during this first experiment was cool and wet.

35

FIGURE 9. Effect of temperature on fecundity of aphids collected in the field andkept at constant
temperature in the laboratory. Each point is a mean of about 20 adult aphids.

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976 47

The second experiment, in warmer weather,
was done in duplicate to see how much
variation might occur between replicates. The
third experiment, during a period of cloudy,
warm weather, was started at variable aphid
densities, partly to check for density-dependent
restrictions on the rate of aphid increase, and
partly to compare the predation rate at dif-
ferent prey densities. Each experiment ran until
the alfalfa plants were too large for accurate
sampling (§ 4), or until an incipient fungal
epidemic threatened the aphids. After each ex-
periment, the surviving coccinellids were
removed and counted, the cages were sprayed
with a short-lived insecticide, and the alfalfa
was cut and allowed to grow for two weeks

1.0

0.87 NOT MOVING

Ss
a

°
b

°
SS)

°
a

MOVING

COCCINELLIDS PER FOOT - ROW

°
rs

0.2

12 14 16 18
TEMPERATURE (C°)

before the next experiment began.

Standard counts, as described in § 4, never
revealed more than 25% of the true beetle num-
bers, even at high temperatures up to 28° and
at low aphid densities. The ladybirds spent
most of their time in the stubble at the base of
the alfalfa. This observation itself can explain
the remaining discrepancy: the beetle counts in
the field (Fig 8) almost certainly un-
derestimated the actual numbers present. The
number of moving beetles (Fig. 10) increased
steadily with temperature, but there was no
corresponding decrease in the observed number
of stationary beetles, which might be sa
if all beetles had been visible.

20 22

FIGURE 10. Effect of ambient temperature on numbers of C. trifasciata observed moving (10B),
and not moving (10A), in field counts (cf. Fig. 7). Each point is the mean of counts from about
60 row-feet.

Analysis of cage experiments

Details of the individual experiments appear
in the legends to Figs. 11-13. Each figure shows
the means of successive aphid samples,
together with the simulation curves generated
by the computer. All broken curves refer to
control cages without beetles. These curves all
show the same rate of aphid increase, or, in
other words different sections of the same
curve of exponential population increase. They
are not exponential at the start of the ex-
periment, because of the initial, non-
equilibrium, age-distributions. The relative rate
of increase is the same at all aphid densities,
but it is far less than would be expected from
the aphids’ fecundity, estimated in the
laboratory. In fact, the broken curves are

generated by imposing a 70% reduction in
fecundity. We do not know the cause of this
discrepancy, which has occurred consistently
throughout the whole study, and in later work.
Probably it means that fecundity in the field
(which cannot be measured directly) is only
30% of that in ideal laboratory conditions. The
discrepancy might alternatively be due to
predation, at a constant rate of 70% throughout
the season, acting on newly-born aphids only
(to give the right age-distributions). In the con-
trol cages, we had to impose extra mortality of
1.3%/q on aphids of all ages. This ‘background’
mortality is ascribed to the numerous hunting
spiders Erigone metlakatla Crosby & Bishop,
observed in the cages. There was also a certain
amount of parasitization, which we estimated

48 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), Dec. 31, 1976

from counts of mummies (§ 4), and which in-
creased from 0.3%/q in the first experiment to
1.0% in the third.

The ‘disturbed’ curve in Fig. 11 refers to a
cage which contained no coccinellids, but in
which the alfalfa was disturbed by hand four
times/q, causing some aphids to fall off the
plants, as they do when approached by a
ladybird. If such aphids do not climb back onto
a new plant, the rate of population increase will
be reduced. There evidently is some reduction,
but not much. The disturbance caused by a
beetle is much less than that which we made by
hand.

The unbroken curves in Figs. 11-13 were
generated by imposing the additional mortality
attributed to beetle attack. They assume that
the predation occurs independently of the
background mortality, i.e. that the overall sur-
vival rate is the product of the two separate
survival rates. This is a very reasonable assum-
ption, because each coccinellid searches in-
dependently of other predators and parasites.

The ladybirds also suffered mortality,
mostly from predation by a _ web-spinning
spider, Enoplognatha ovata (Clerck). We could
not spray to control the spiders, for fear of
provoking an outbreak of mites. Therefore,
although we introduced known numbers of male
and female beetles during each experiment, we
do not know the exact numbers alive at any
given time. After the end of each experiment,
we collected ladybirds from the cages until few,
if any, remained. We then computed the sur-
vival rate needed to reduce the initial numbers
of beetles introduced to the final numbers
recovered. The mortality proved to be rather
more than 2%/q in all three experiments. The
numbers of beetles shown in Figs. 11-13,
although accurate at start and finish, thus
depend on the assumption of constant survival
rates. Our subsequent conclusions are not
seriously affected by reasonable deviations
from that assumption. At the end of each ex-
periment we took bag samples (§ 4) to convert

the numbers of beetles and mummies to a per-

terminal basis.

Figs. 11-13 cover a _ range of field
temperatures and aphid densities. We used
more than twice as many beetles per cage in
cool (Fig. 11), as in warm conditions (Fig. 13).
If our understanding of coccinellid predation is
reasonably complete, we should be able to ap-
ply a single formula (with appropriate tem-
peratures, beetle numbers and initial aphid den-
sities) to all three experiments. It is possible to
do so. Every curve in Figs. 11-13 is computed
by the same program; and all the parameters in
that program, except three, have been
estimated from other sources. Two parameters,
viz. aphid fecundity and background mortality,
were dictated by the aphid numbers observed

in the control cages. The third parameter is the
coefficient which specifies how beetle activity
increases with temperature (§ 3). The curves
require that beetle activity be, on average,
0.018 times the temperature above 4°C. This is
merely an overall parameter chosen to reconcile
the unbroken curves with the observations. The
computer program, not listed here, is very
similar to Appendix 6. We think that the
agreement is good, bearing in mind the dif-
ferences between replicates in Fig. 12. It could
easily be improved by minor adjustments. The
only serious discrepancy is in Fig. 11, where the
computer predicts that increased temperatures,
towards the end of the experiment, should have
prevented the final increase in aphid density. In
fact the weather remained continuously cloudy,
which may have depressed beetle activity; we
certainly need further information about the ef-
fect of weather on beetle activity. Otherwise,
the agreement between observation and predic-
tion is acceptable, and so we have a single for-
mula, given in § 3 and used in Appendix 6,
which satisfactorily predicts the predation rate
over a wide range of temperatures and prey
densities.

DISCUSSION

It does not follow that the components of
the formula necessarily reproduce the biological
details correctly. For example, we have ignored
the fact that the hunger curve, used in the field
predation model of § 3, refers to C. un-
decimpunctata (Fig. 2A), not to C. trifasciata.
The hunger curve for C. trifasciata (Fig. 2B)
was estimated at the end of the investigation,
using beetles taken from the field cages. The
observations in Fig. 2B were taken at 20°C. The
curves in Fig. 2B predict a maximal con-
sumption/q of 5.5 mg/beetle, as compared with
the 5.7 mg for C. undecimpunctata, used in § 3.
Thus the two species agree very closely in this
respect, and there is no need to change the for-
mula of § 3. But P.M. Ives informs us that
female C. trifasciata, kept in the laboratory and
fed ad libitum, ate only 4.4 mg per q on
average. The reason is undoubtedly that given
in § 3, that the initial hunger level of 0.88, used
in our calculations, is too high for a well-fed
beetle. There is therefore some residual ignoran-
ce about the voracity of coccinellids in the field,
but it is unimportant here: for the computer
program generates the same unbroken curves
in Figs. 11-18, whatever the maximal con-
sumption (within reasonable limits), provided
that the temperature coefficient for beetle ac-
tivity is altered accordingly. Thus the residual
errors in beetle activity cancel the remaining
errors in beetle voracity, to give identical
predictions of the predation rate.

Whatever the true average level of coc-
cinellid activity may be, it is certainly very low.
Watching the predation process in the

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976 49

20
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BEETLES
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24 A BEETLES /
O CONTROL - UNDISTURBED UNDISTURBED re
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MEAN APHIDS PER TERMINAL

SO

20 30
PHYSIOLOGICAL TIME (QUIPS)

FIGURE 11. First cage experiment. In the lower section the points represent observed sample
means but the curves were computed. Each sample in Figs. 11-13 contained about 27 plants,
except at the start and end of each experiment, when each sample contained about 36 plants. The
curves are largely independent of the observations—see text. The ‘undisturbed’ curve shows the
exponential increase in the absence of ladybird predation. The ‘disturbed’ curve is computed on
the assumption that mechanical disturbance of the plants, causing some aphids to fall off, causes
no mortality. The solid line curve predicts the effect of predation by the numbers of beetles shown
in the middle section, at the weighted average temperatures shown in the upper section. Compared
with Figs. 12 and 13, temperatures were low and the number of beetles needed to show any
obvious effect was consequently large. There was a fourth cage containing half the number of
beetles shown here, which gave results intermediate between the ‘undisturbed’ and unbroken
curves. To avoid confusion, those results are not shown.

50 20 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976
La
ac ©
Or 15
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A BEETLES — CAGE 2 x /
® CONTROL - CAGE 3 ; eg
© CONTROL - CAGE 4 f

MEAN APHIDS PER TERMINAL

10 20 30 40
PHYSIOLOGICAL TIME (QUIPS)
FIGURE 12. Second cage experiment. There were two replicate cages containing coccinellids, and
two controls. Only one curve has been computed for each pair of cages. The differences between
cages 1 and 2, and between 3 and 4, measure the variation experienced between replicates. These
differences must be borne in mind during any examination of Figs. 11-13. Beetle numbers were
the same at the start, but declined more in cage 1 than in cage 2, which partly explains the
difference in aphid numbers. The number of beetles shown in the middle section is the

average for the two cages.

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976 51

Ww 20
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4S BEETLES - CAGE 2 y ‘
® CONTROL — CAGE 3 /
F © CONTROL —- CAGE 4 /

MEAN APHIDS PER TERMINAL

40

10 20 30
PHYSIOLOGICAL TIME (QUIPS)

FIGURE 13. Third cage experiment. Different cages were deliberately started at different aphid
densities, to examine the effects of aphid density on predation rate and rate of aphid increase.
The curves predicted for cages 2 and 3 disagree with the data, but only within the limits of varia-
tion revealed in Fig. 12 (see text). The curve for cage 2 remains level from q 11 to q 25, but then
begins to rise as temperatures and beetle numbers decline. This illustrates the principle that no
equilibrium between aphid and coccinellid numbers can be permanent. Figs. 11-13 have different
scales for aphid density. The number of beetles shown in the middle section is the average for the
two cages: More survived in cage 1 than in cage 2, and the curves are computed accordingly.

52 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976

laboratory, we saw a hungry predator
anxiously scouring its universe for prey. Wat-
ching a population of beetles in a field cage in
conditions almost identical with those of the
open field, we saw the ladybirds spending a
good three-quarters of their time motionless in
the stubble. In the laboratory, there was
nowhere to hide. The contrast between
laboratory and field could not be greater.

The cage experiments give some _in-
formation about possible interactions between
predation and parasitization rates. If
parasitized aphids suffer a higher predation
rate than unparasitized, there will accordingly
be a relative shortage of parasite mummies in
the cages containing beetles. No large or con-
sistent difference was seen: such heterogeneity
as did occur was restricted to the first ex-
periment, where the parasitization was begun
by emerging overwintered adults.

The new formula for predation rate still does
not resolve the discrepancy between observa-
tion and prediction in Fig. 8. In fact, it makes it
worse, because beetle activity is less than we
previously supposed (§ 4). We now need four
times as many beetles as were actually observ-
ed, to produce the decline in aphid numbers
shown in Fig. 8, 35-79 q. We can readily believe
that, as in the field cages, there were four times
as many beetles present as appeared in the
samples. Although we have a good estimate of
the predation rate, we still have no sure way of
sampling beetle numbers in the field. Stan-
dard methods using sweep nets, walking
counts, or suction machines, are hopelessly
inaccurate. Our intensive counts find only a
fraction of the numbers actually present, and
that fraction must vary with aphid density,
temperature, and probably the time of day.
The adult coccinellid, at first sight so conspicu-
ous an animal, is in fact very cryptic.

6. CONCLUSIONS
Laboratory v. field studies

The coccinellid-aphid relationship, observed
in the field, differs from that in the laboratory
in three major respects. The distribution of
prey affects the predation rate in the labora-
tory but not in the field (§ 3). Predators observ-
ed in the laboratory were more active than
those in the field (§ 5). Temperature has an
overriding effect in both laboratory and field —
a fact which would not be noticed at constant
temperature in the laboratory. Moreover, it
has a differential effect on predation rate, and
on population dynamics of the prey. This
means that predation and population studies
on insects must include temperature as an
essential component, and that studies of preda-
tion alone, unlinked to population dynamics
can be meretricious. It also means that labora-

tory studies alone are unreliable, because some
vital aspect of the true, i.e. the field relation-
ship may be completely overlooked in the
laboratory.

Holling (1966) pioneered the detailed behav-
ioural and physiological approach to the study
of predation and discussed the advantages of
his approach, over more superficial methods
(Holling 1964). Holling’s work was so detailed
that it could be done only in the laboratory:
but the method can be simplified and applied in
the field, to predict predation rates which can
be reconciled with the population dynamics of
the prey. Thus Holling’s approach, offering
precise predictions over a wide range of contin-
gencies, may be combined with the broader
realism of quantitative field studies, as first
attempted by Morris (1963). Two major con-
clusions are therefore that (1) laboratory
studies of ecological relationships must not
be trusted until verified in the field, and (2)
it is in fact possible to make detailed predator-
prey studies in the field, to explain the obser-
ved impact of predation on the prey population.

Stability

The coccinellid-pea aphid _ relationship
sharply contradicts existing theories on insect
predators and prey, and of ecological stability.
It permits no steady-state, or equilibrium, be-
tween predators and prey. It is true that, for
any given aphid density and temperature, there
is some number of coccinellids which could keep
aphid numbers constant, once the aphid age-
distribution had settled to a steady-state: but
the ladybirds rarely approach the necessary
predator prey ratio, even at high temperatures.
Moreover, the relationship would be unstable.
Curve C (Fig. 5) shows a monotonic increase
of survival rate with aphid density, so that
any chance increase in aphid numbers will allow
the aphids to gain, and the beetles could not
thereafter restore the balance. Conversely,
the slightest decrease in aphid numbers would
allow the beetles to drive the aphids towards
extinction. Moreover, the required number of
beetles depends critically on temperature, so
that even a slight change in temperature would
upset the equilibrium. There is nothing in the
coccinellid-aphid functional relationship to
prevent either a continual increase in aphid
numbers, or a continual decline towards extinc-
tion. We have twice observed such a decline in
the field (Figs. 1 and 8), which was arrested
because the predator left the field when the
prey density became very low. The con-
ventional definition of stability (Hassell & May
1973), as a tendency to return towards some
steady-state or equilibrium (which need never
be actually reached), does not apply here, where
the relationship is completely unstable, but
extremely resilient (Holling 1973). The

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976 De

functional response is unstable, and the rela-
tionship is stabilized only by the predator’s
numerical response.

Some technical considerations

To assess the impact of predators on their
prey populations, we must compare the num-
bers of prey actually observed, with the num-
bers that would be observed, in identical field
conditions, but in the absence of the predators.
This is very difficult to do, especially if the
comparison is to cover all conditions normally
encountered in the field. The method used here,
of dissecting the predation process and tying
it into the population dynamics of the prey,
is perhaps the only fully reliable method used
so far. The chief technical difficulty in the
field was not to observe the process of preda-
tion but to estimate the density of predators,
for which we still have no satisfactory method.

Several theories of predation embody the
concept of a predator’s, or parasite’s, area of
search. Our predator is limited at low prey
densities, not by its capacity for prey, but by
the time available to search for them. This is
equivalent to a limited area of search, since the
predator cannot search the whole area within
the time available. We believe it is better to
think in terms of timing, rather than of area of
search, partly because it emphasizes the
dynamic nature of the predator-prey relation-
ship, and partly because the aphids play hide-
and-seek with the beetles. Even if a ladybird
could search the whole area, it still would not
find all the aphids.

This study offers cold comfort for biological

control workers. Since the coccinellid-aphid
relationship is unstable and incapable of a
steady-state, we cannot expect the coccinellids
to keep aphid numbers low for any length of
time. Usually the beetles merely slow the in-
crease in aphid numbers. At high temperatures,
the beetles can certainly depress aphid numbers
(Figs. 1 and 8); but we have seen this happen
only during unusually warm periods early in
the season; and even then, the beetles quickly
left the field in search of other prey. The
coccinellids’ double temperature requirement,
and their mobility, make them _ ineffective
predators, in that they rarely restrict the
density of their prey. To use ladybirds as
effective and permanent agents for biological
control, we must direct their natural behaviour
to a quite unnatural end.

7. ACKNOWLEDGEMENTS

We are deeply indebted to Mrs. Anthea
Bryan and Mr. David Raworth for their very
skilled and painstaking work. We thank Mr.
Rick Chorney, Mrs. Catherine Fockler, Mr.
Murray Isman, Miss Katherine White, Miss
Shiona Whyte, and Mr. Donald Wood for their
help: Dr. A. P. Gutierrez and Dr. C.S. Holling
for technical advice: Dr. Holling and Dr. H. R.
MacCarthy for carefully reviewing the manu-
script: Mr. J. H. Severson for drawing the
Figures: and Mr. Don Pearce and his staff for
agricultural operations. The National Research
Council of Canada paid part of the bill with
Operating and Development Grants. The
spiders were identified by Dr. C. D. Dondale.

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Morris, R. F. and C. W. Bennett. 1967. Seasonal population trends and extensive census methods
for Hyphantria cunea. Can. Ent. 99, 9-17.

Wratten,S.D. 1973. The effectiveness of the coccinellid beetle, Adalia bipunctata (L.), as a preda-

tor of the lime aphid, Eucallipterus tiliae L. J. Anim. Ecol. 42, 785-802.

Appendices 1, 3, 5 and 6 will be sent upon
request to either author.

Appendix 2
Algorithm to compute physiological time in
the field

This method was devised by Morris &

Bennett (1967), but the algorithm has not been
published. Successive daily maximum and mini-
mum field temperatures are stored in an array
X. The algorithm fits a sine curve between two
successive values of X, and integrates it above
the threshold temperature thresh. It there-
fore calculates two increments (from min to
max and from max to min) for each calendar
day. Each increment, B, is calculated in day-
degree units if the original temperatures
are Fahrenheit, B will be in a day-°F., and
similarly for Celsius. The algorithm is applied
to successive pairs of values X(I), X(I+1),
where I =1, 2,3...
IF(X(1I).LE.X(I+1))GO TO 2
XMAX=X(I)
XMIN=X(I+1)
GO TO 4
2 XMAX=X(I+1)
XMIN=X(I)
4 Y=XMAX+XMIN-2.* THRESH
IF(XMIN.LT.THRESH)GO TO 6
B=.25*Y
GO TO 10
6 IF(XMAX.GT.THRESH)GO TO 8
B=0.
GO TO 10
8 T=ARCSIN(Y/(XMIN-XMAX))
B=.125*Y*(1.-.63661977*T)+
.079577472/(XMAX-XMIN)*COS(T)
10 CONTINUE

Appendix 4

Derivation of the expression for
survival rate

The problem is to fit a curve to the data
points in Fig. 5. At high aphid densities, when
the beetles have no trouble in finding aphids,
the survival rate s must approach the ‘random
search’ survival rate exp (-kb/a), for the
appropriate value of k, which is deduced as
follows: In the model, each beetle starts with
hunger H=0.88, corresponding to a starvation
time of 15 hours. If such a beetle were suddenly
presented with all the aphids it needed, it would
eat an average of 5.7 mg. of aphids in the first
q. This quantity is deduced from the hunger
curve when an average beetle eats its fill, and
thereafter eats a whole aphid whenever it be-
comes hungry enough to do so. Therefore,
the beetle will eat 5.7/AWT aphids, each of
weight AWT (Table 1), so that the appropriate
value of & is 5.7/AWT. Curve A (Fig. 5) is the
random search survival s =exp(-5.7b/(AWT-
xa)), or for mathematical convenience

-log s=5.7 b/(AWT x a)
This defines the required curve at the top end
of the scale in Fig. 5. We shall now derive a
theoretical value for -log s at the other end of
the scale, when aphid density is very low. In the
model, a beetle takes 51.3 seconds to visit one
plant, provided that no aphid is found and
eaten. At 18.5°C, 1 q lasts 40,000 seconds, in
which time each beetle can visit 780 plants.
Since there are 6 beetles per plant, each plant
will receive an average of m=780 b visits/q.
Any given plant will actually be visited r times,
where r follows the Poisson distribution with
mean, i.e. the probability of exactly r visits

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976 55

is e’"mT/r!. We shall suppose that the aphid
density is almost zero, so that most plants
carry no aphids, but a few plants have a single
aphid. In such circumstances, the beetles will
be completely hungry (H=1). The probability
of an aphid being eaten, when a beetle visits
its plant, is PE, estimated from field observa-
tion to be 0.0205, which is the value of PE
used in the field predation model of Appendix
3 to compute the data points of Fig. 5. The
probability that one aphid survives one visit
by the beetle is therefore (1-0.0205), and so
the probability that it survives r successive
visits is (1-0.0205)". The average survival rate
s will therefore be the average value of this
expression ffor _ all
¥(1-0.0205)"e"™m"/r!, which reduces’ to
s=exp (-0.0205 m). Since m=780 b, it follows
that, at near-zero aphid density,

-log s =0.0205 x 780 b. (2)
The required survival curve must therefore
agree with expression (1) at high aphid densi-
ties, and with (2) when the aphid density a
approaches zero. There are many such curves,
but an obvious one (mathematically speaking)
to try is:

-log s = 5.7b [1 - exp (-ka)]/(AWT xa) (8).
This expression approaches (1) for large values
of a, and it also satisfies the requirement stated
in §3, that if the beetle density 6 is doubled,
the survival rate s is squared. Expression (3)
agrees with (2) as a tends to zero if the appro-
priate value, namely

0.0205 x 780 x AWT / 5.7 (4).
is chosen for the parameter k. When the value

1.0

0.9

values of jy, i.e.

of AWT for second-instar aphids is substituted
in (3), we get curve B of Fig. 5.

It is obvious from Fig. 5 that curve B still
does not fit the data points very well. Although
there are many other curves which satisfy
the requirements of (1) and (2), it is unlikely
that any equally simple formula will give a
better fit than curve B. Rather than try one
formula after another, it is better to tailor (3)
to fit the data points. In expression (3), the
term (-5.75/AWT x a) represents the random
search of expression (1), while the term
[1-exp(-ka)] reflects the fact that, at low aphid
densities, the beetle has insufficient time to
catch all the aphids it wants. Indeed, when ex-
pression (4) is substituted for k, the value of
ka turns out to be the number of aphids which a
beetle can expect to catch in a given time, divi-
ded by the number of aphids required to
keep the beetle satiated during that time.
Mathematically speaking, we could alter the
terms for either random search or insufficient
time; but since curve B gives a poor fit
only at small aphid densities, it makes better
biological sense to modify [1 - exp(ka)]. The
value of k is evidently not constant, but must
vary with the aphid density a. Its value ko,
when a=O, must still be given by (4). From
each survival rate computed by the predation
model (Fig. 5), we deduce the appropriate value
of k in (3). Fig. 14 shows the values of k/ko
for varying aphid densities. When a ‘greater
than’ 4, the value of k/ko is of no concern be-
cause the insufficient time factor (1 -exp/-ka))
then has little effect on the survival rate.

us K/K,= 0.654 + 0.026/(a+ 0.075)

2
APHID DENSITY

FIGURE 14. Values of k/ko deduced from Fig. 5 and the curvilinear regression, weighted according
to the accuracy of each point.

56 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976

In Fig. 14, a rectangular hyperbola has been
fitted to the values of k/ko by non-linear re-
gression, weighted according to the accuracy
of each point, giving the formula k/ko=0.654
+0.026/(a+0.75). This formula contains two in-
dependent empirical parameters, because
k/ko must equal unity when a=O. We call
k/ko the ‘hunger correction’, for the following
reason: the curve for k/ko remains unchanged
when we alter PE, PL, TS, or the instar of the
aphids concerned. Such changes (with the ex-
ception of PL) will, of course, alter the sur-
vival rate s directly from the formula for ko.
However, an acceleration of the _ beetle’s
digestion (i.e. of the rate at which its hunger
H increases with time) does increase the value
of k/ko somewhat, whenever the aphid density,
a, exceeds one per plant, but has little effect
at lower densities, when the beetle is con-
tinuously very hungry. For example, accord-
ing to the predation model, the beetle’s average
relative hunger H is 0.64 at aphid density
a=1, but 0.91 at a=0.1. It appears, then, that
the shape of the k/ko curve in Fig. 14 is largely
due to the fact that, the fewer aphids there are,
the hungrier the beetle remains, and the more
anxiously it searches. It must be remembered

that changes in hunger level affect not only
k/ko, but the random search term as well.
We thus end up with expression (3), but
with
k=0.0205 X780 x AWT [0.654 + 0.026/(a +0.075) |
/5.7 (5).
We then get curve C in Fig. 5, which fits the
computed data points well. Finally we must
reconsider the value of PE, since it varies
according to the aphid instar. In face, PE
equals some _ constant times FACTE
(Table 2). We recorded the instar of every aphid
which we saw captured in the field, and the
average value of FACTE for those aphids
is 1.07. To reproduce the _ estimated
overall value of PE (0.0205), we _ write
PE=0.019 x FACTE, since 0.019 x 1.07=0.0205.
The figure 0.0205 in (5) must therefore be re-
placed by 0.019 x FACTE, and we then have the
formula for survival rate used in Appendix 5.
This means, incidentally, that the estimated
overall value 0.0205 should not be used in
Appendix 3, since FACTE=1.28 for second-
instar aphids (Table 2), giving a corresponding
PE=0.019 x 1.28=0.024. This error does not
affect the analysis in this Appendix, since the
k/ko curve is unaffected by changes in PE.

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976

57

THE APHIDS (HOMOPTERA: APHIDIDAE)
OF BRITISH COLUMBIA
4. FURTHER ADDITIONS AND CORRECTIONS!

A. R. FORBES AND CHO-KAI CHAN

Research Station, Agriculture Canada
Vancouver, British Columbia

ABSTRACT
Twenty-five species of aphids are added to the taxonomic list of the
aphids of British Columbia. New host records, a few corrections, and
some name changes are also included.

INTRODUCTION

Two previous lists of the aphids of British
Columbia recorded 261 species collected from
294 hosts or in traps (Forbes, Frazer, and
MacCarthy 1973; Forbes, Frazer and Chan
1974).

The present list adds 25 species of aphids
(indicated with an asterisk in the list) and 213
aphid-host plant associations to the previous
lists. One hundred and twenty-nine of the new
aphid-host plant associations are _ plant
species not in the previous lists. The additions
bring the number of known aphid species in
British Columbia to 286. Aphids have now been
collected from 423 different host plants.

The present paper includes a few corrections
to the previous lists and some name changes
in conformity with current usage in aphid
taxonomy. The aphids are arranged alpha-
betically by species. The location of each
collection site can be determined from Table 1
or from the tables of localities in the previous
papers.

The complete data for all collections have
now been computerized, so that up-to-date
aphid or host lists are easily available. The
computer programming is described in detail
elsewhere in this Journal (Raworth, and
Frazer 1976).

‘Contribution No. 387, Research Station, 6660 N. W. Marine
Drive, Vancouver, British Columbia, V6T 1X2.

LIST OF SPECIES

ABIETINUM (Walker), ELATOBIUM
Picea sp: Vancouver, May 3/74, May 7/75.
AEGOPODII (Scopoli), CAVARIELLA
Petroselinum crispum: Vancouver,
Apr. 29/75.

ALBIPES Richards, THELAXES
Quercus prinus: Vancouver (UBC), Jun 6/75,
sti 1/75.

ALNI (DeGeer), PTEROCALLIS
Alnus rubra: Vancouver, Sep 26,75.

ALNIFOLIAE ALNIFOLIAE — (Williams),
PROCIPHILUS Previously listed as
PROCIPHILUS ALNIFOLIAE Williams.
Amelanchier canadensis: Vancouver (UBC),
Jun L1/ 75,

ANNULATUS (Hartig), TUBERCULOIDES
Quercus garryana: Vancouver (UBC),
Jum dy 75,
Quercus robur: Vancouver, Sep 26/75; Van-
couver (UBC), Jun 12/74.
Quercus robur var fastigiata:
(UBC), Jun 18/75.
Quercus sp: Vancouver, Jun 2/73.

ASCALONICUS Doncaster, MYZUS
Arctostaphylos uva-ursi: Vanncouver (UBC),
May 5/75.

Fragaria Sp: Vancouver (UBC), May 15/74.
Lactuca sp: Vancouver, Apr 5/58.
Ranunculus occidentalis: Vancouver,

May 20/75.

Rheum rhaponticum: Vancouver, May 20/75.
Viola sp: North Vancouver, May 25/75.

Vancouver

TABLE 1. Localities where aphids were collected, with airline distances from reference points.

Locality Reference
Point

Bridesville Kelowna
Delta Vancouver
Lac La Hache Williams Lake
Laidlaw Vancouver
Robson Creston
Salmon Arm Kamloops
West Vancouver Vancouver

Dir. Distance
km mi
S 94 59
S 24 1
SE 58 36
E 104 65
NW 93 58
E 72 45
W 13 8

58 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976

*AUREUS Richards, BETULAPHIS
Betula sp: Terrace, Jul 12/60 (Richards
1961a).

AVENAE (Fabricius), MACROSIPHUM
Avena sativa: Agassiz, Jul 28/69.
Juncus articulatus: Vancouver (UBC),
Aug 7/74.
Juncus bufonius: Vancouver (UBC),
Aug 7/74.
Scirpus validus: Vancouver (UBC), Aug 9/74.
Triglochin maritimum: Vancouver (UBC),
Aug 9/74.
Zea mays: Agassiz, Jul 28/69.

BAKERI (Cowen), ROEPKEA
Crataegus douglasii: Vancouver (UBC)
Jun 5/75.

Prunus avium: Summerland, Oct 25/74.
Prunus domestica: Summerland, Oct 25/74.
BERBERIDIS (Kaltenbach), LIOSOMAPHIS
Berberis aquifolium: Vancouver, May 15/73;

Vancouver (UBC), Jul 8/74.
Berberis hybrido-gagnepaini:
(UBC), Jun 19/75.
BICOLOR BICOLOR (Oestlund),
PTE ROCOMMA
Populus nigra var italica: Vancouver (UBC),
Apr 24/74, Apr 26/74, Apr 30/74, May 9/73.
Populus sp: Vancouver (UBC), May 21/73.
Populus trichocarpa: Vancouver (UBC),
May 21/73.
Salix sp: North Vancouver, May 20/73.
BURSARIUS (Linnaeus), PEMPHIGUS
Populs nigra var italica: Vancouver (UBC),
Jun 28/73.

CALIFORNICUM (Clarke), MACROSIPHUM
Salix scouleriana: Vancouver (UBC),
Jun 25/74.
Salix sp: Vancouver (UBC), Jun 8/73.

*CALLUNAE Theobald, APHIS
Calluna vulgaris: Vancouver (UBC),
Jul 18/74, Jul 19/74.

CARAGANAE (Cholodkovsky),

ACYRTHOSIPHON
Caragana arborescens:
Aug 14/75.

CARDUI (Linnaeus), BRACHYCAUDUS
Prunus domestica: Summerland, Oct 25/74.

CASTANICOLA Baker, MYZOCALLIS
Castanea dentata: Vancouver (UBC),
Sep 4/75.

CERASI (Fabricius), MYZUS
Prunus avium: Summerland, Oct. 25/74.
Prunus cerasus: Vancouver (CDA), Apr 18/75
(In Rearing Room).
Prunus emarginata: Creston, May 30/75,
Jun 28/75; Robson, Jun 29/75.
Prunus serrulata var shirofugen: Vancouver,
May 13/75.
Prunus sp: Creston, Jun 28/75; Summerland,
Jun 3/75.

Vancouver

Vancouver (UBC),

CERASIFOLIAE (Fitch),
RHOPALOSIPHUM
Prunus virginiana: Summerland, May 28/75,
Jun 19/75.
Prunus viginiana var demissa: Bridesville,
Jun 4/75: Robson, Jun 29/75.

CIRCUMFLEXUS (Buckton),

AULACORTHUM
Campanula persicifolia: Vancouver,
Aug 19/75.

Oxalis corniculata:
Aug 19/75.

CIRSII (Linnaeus), DACTYNOTUS
Cirsium arvense: Ladner, Jul 17/74.

CLAVICORNIS Richards, AULACORTHUM
Rosa sp: Williams Lake, Jun 15/56.

CORNI (Fabricius), ANOECIA
Cornus obliqua: Vancouver (UBC), Oct 24/75.

CORNIELLA Hille Ris Lambers, APHIS
Cornus ‘Eddie’s White Wonder’: Vancouver
(UBC), Sep 9/75.

Cornus florida: Vancouver (UBC), Sep 9/75.
Cornus florida var pluribracteata: Vancouver
(UBC), Sep 9/75.

Cornus kousa: Vancouver (UBC), Sep 9/75.
Cornus mas: Vancouver (UBC), Sep 11/75.
Cornus obliqua: Vancouver (UBC), Sep 11/75.
Cornus racemosa: Vancouver (UBC),

Sep 9/75.

CORYLI (Goeze), MYZOCALLIS
Corylus cornuta: Vancouver (UBC), Aug
27/14, Oct. 2/775.

*COWENI (Cockerell), TAMALIA
Arctostaphylos uva-ursi: Vancouver (UBC),
Sep 12/75.

CRACCIVORA Koch, APHIS
Holodiscus discolor: Brentwood, Jul 5/59.

CYPERI (Walker), TRICHOCALLIS
Carex sitchensis: Vancouver (UBC),

Aug 9/74.

DIRHODUM (Walker), ACYRTHOSIPHON
Crataegus oxyacantha ‘Paul’s Scarlet’:
Vancouver (UBC), Jun 5/75.

DORSATUM Richards, AULACORTHUM
Gaultheria shallon: Vancouver (UBC),

Sep 2/75.

ELAEAGNI (Del Guercio), CAPITOPHORUS
Previously listed as ELAEGNI (del Guercio)

due to a typographical error.

*ENIGMAE Hottes & Frison,
RHOPALOSIPHUM
Typha latifolia: Vancouver (UBC), Aug 9/74.

*EPILOBII Kaltenbach, APHIS
Epilobium watsonii: Vancouver, Jun 11/73.

ERIOPHORI (Walker), CERURAPHIS
Carex sitchensis: Vancouver (UBC), Aug
9/74.
Scirpus microcarpus: Vancouver (UBC),
Aug 9/74.
Viburnum opulus: Vancouver, Apr 22/73.

Vancouver, Jul 23/75,

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), Dec. 31, 1976 59

EUPHORBIAE (Thomas), MACROSIPHUM
Chaenomeles japonica: Vancouver, Jun 13/75.
Cornus stolonifera: Vancouver (UBC),

Jul 15/75, Aug 5/75, Aug 27/74.

Dahlia sp: Vancouver, Aug 1/74.

Deutzia gracilis: Vancouver (UBC),

Jun 19/75.

Deutzia x rosea var carminea: Vancouver
(WBC), Jun 18/75.

Dicentra formosa: Vancouver (UBC),

Jun 10/74.

Escallonia x edinensis: Vancouver (UBC),
Sep 4/75.

Forsythia sp: Vancouver (UBC), Jun 27/75.
Fragaria sp: Victoria, May 30/57.

Fuchsia hybrida: Vancouver, Aug 27/75.
Gynura aurantiaca: Richmond, Nov 4/75.
Halesia carolina: Vancouver (UBC),

Jun 26/75, Jul 22/75.

Hypochaeris radicata: Vancouver (UBC),

gun 13/75.

Ilex aquifolium var aureo-marginata: Van-
couver (UBC), Jun 18/75.

Iris kaempferi: Vancouver (UBC), Aug 28/74.
Lapsana communis: Vancouver, Jun 13/75.
Liriodendron tulipifera: Vancouver (UBC),
Jun 9/75, Aug 14/75.

Montia sibirica: Vancouver (UBC), Jun 13/75.
Philadelphus lewisii: Vancouver (UBC),

Jul 15/75.

Philadelphus lewisii var gordonianus: Van-
couver, Apr 20/73; Vancouver (UBC),
Jun 22/59, Aug 8/59.

Philadelphus x virginalis: Vancouver (UBC),
May 16/75, Jun 17/75, Jun 18/75, Jun 26/75,
Jun 27/75.

Rosa sp: Vancouver, May 16/73, May 16/74.
Salix sp: Vancouver, Jun 13/73.

Spiraea douglasii: Vancouver (UBC),

Jun 25/74, Jul 15/75.

Verbena x hybrida: Trout Creek, Sep 3/65.
Vinca minor: Vancouver (UBC), Jun 19/75.

FABAE Scopoli, APHIS
Amelanchier canadensis: Vancouver (UBC),
Jun 11/75.

Callistephus chinensis: Vancouver (CDA),
Aug 7/75 (In Greenhouse).

Chenopodium album: Vancouver (UBC),
Aug 11/75.
Cuscuta subinclusa: Vancouver (CDA),

Aug 7/75 (In Greenhouse).

Deutzia gracilis: Vancouver (UBC), Jun
19/75.

Euonymus alatus: Vancouver (UBC),

Sep 4/75.

Euonymus europaea: Vancouver (UBC),
May 23/75, Sept 9/75, Sep 22/75.

Euonymus latifolius: Vancouver (UBC),
Sep 9/75.

Fatsia japonica: Vancouver, Jul 13/75.
Ficus carica: Vancouver (UBC), Jun 23/75.
Hedera helix: North Vancouver, May 16/73.

Liriodendron tulipifera: Vancouver (UBC),
Aug 14/75.
Matricaria matricarioides: Vancouver (UBC),
oul 217 75:
Philadelphus lewisiti var gordonianus: Van-
couver, Apr 20/73.
Philadelphus sp: Vancouver, Jun 29/71.
Philadelphus x virginalis: Vancouver (UBC),
May 16/75, Jun 18/75.
Sassafras albidum: Vancouver (UBC),
Sep 9/75.
Viburnum _ trilobum:
Jul 3/75, Sep 3/75.
FAGI (Linnaeus), PHYLLAPHIS
Fagus sylvatica var purpurea: Vancouver,
May 14/73.
FARINOSA Gmelin, APHIS
Salix sp: West Vancouver, May 25/73.
FIMBRIATA Richards, FIMBRIAPHIS
Arctostaphylos uva-ursi: Vancouver (UBC),
Jun 2/75.
Fragaria sp: Agassiz,
Island, May 23/57.
FRAGAEFOLII (Cockerell),

CHAETOSIPHON
Fragaria sp: Lulu Island, Jul 17/57; Van-

couver, Apr 24/59; Vancouver (UBC),
May 15/74.
Rosa sp: Summerland, Jun 19/75.
FRAGARIAE (Walker), MACROSIPHUM
Juncus bufonius: Vancouver (UBC),
Aug 7/74.
Rubus discolor: Vancouver (UBC), Jun 12/74.
Scirpus validus: Vancouver (UBC),
Aug 9/74.
*GALEOPSIDIS ( Kaltenbach)
CRY PTOMYZUS
Ribes laxiflorum: Vancouver, Aug 3/60. |
*GENTNERI (Mason), FIMBRIAPHIS
Amelanchier laevis: Vancouver (UBC),
Jun 5/75.
Crataegus douglasii: Vancouver (UBC),
Jun 5/75.
Mespilus germanica: Vancouver (UBC),
Apr 28/75, Jun 11/75.

*GLYCERIAE (Kaltenbach), SIPHA
Agrostis alba var palustris: Vancouver
(UBC), Jul 28/74.

GRAVICORNIS (Patch), PARATHECABIUS
Previously listed as THECABIUS GRAVI-
CORNIS (Patch).

HEDERAE (Kaltenbach), APHIS

Previously listed as APHIS PSEUDOHED-

ERAE Theobald.

Hedera helix: North Vancouver, May 16/73.
HELICHRYSI (Kaltenbach),
BRACHYCAUDUS

Chaenomeles japonica: Vancouver, Jun 13/75.

Philadelphus sp: Vancouver, Jun 8/59.

Philadelphus x virginalis: Vancouver (UBC),
Jun 20/75.

Vancouver (UBC),

May 15/75; Lulu

60 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976

Prunus domestica: Robson, May 30/75;
Summerland, Oct 25/74.

Prunus sp: Surrey, May 20/73.

Verbena x hybrida: Trout Creek, Sep 3/65.

HERACLELLA Davis, APHIS

Heracleum lanatum: Vancouver (UBC),
Aug 7/75.

HIPPOPHAES (Walker) CAPITOPHORUS
Polygonum lapathifolium: Vancouver (UBC),
Aug 26/74.

Polygonum persicaria: Pemberton,
Aug 25/75.

*HUMBOLDTI (Essig), SITOMYZUS
Physocarpus malvaceus: Vancouver (UBC),
May 28/75.

*HYDRANGEAE (Matsumura),

RHOPALOSIPHONINUS
Deutzia gracilis: Vancouver (UBC),Jun 19/75.

J UGLANDICOLA (Kaltenbach),
CHROMAPHIS
Juglans sp: Vancouver, May 29/73.
*KNOWLTONI Robinson, MYZODIUM
Callitriche stagnalis: Vancouver
Aug 26/74.
LACTUCAE (Linnaeus), HYPEROMYZUS
Ribes laxiflorum: Burnaby, Jun 6/75.
LACTUCAE (Passerini), ACYRTHOSIPHON
Lactuca sp: Penticton, Jul 27/67.

(UBC),

LAMBERSI MacGillivray, _MASONAPHIS
Gaultheria shallon: Vancouver (UBC),
Jun 17/75.

Ilex altaclarensis: Vancouver (UBC),

Jun 18/75.

Ilex aquifolium: Vancouver (UBC),

Jun 18/75.

Ilex aquifolium var aureo-marginata: Van-
couver (UBC), Jun 18/75.
Rhododendron ‘Directeur Moerlands’:
couver (UBC), Jun 9/75.
Rhododendron ‘Glacier”’:
Sep 3/75.

Van-

Vancouver (UBC),

Rhododendron luteum: Vancouver (UBC),
Jun 6/75, Jun 9/75.
Rhododendron ‘Princess Elizabeth’: Van-

couver (UBC), Jun 6/75, Jun 9/75.

Rhododendron sp: Burnaby, Jun 9/75: Van-

couver, Jun _ 6/75; Vancouver (UBC),

Jun 16/75, Jun 17/75.

LANIGERUM (Hausmann), ERIOSOMA
Pyrus fusca: Delta, May 7/78.

LONGICAUDA Richards, ASPIDAPHIS
Spiraea douglasii: Vancouver (UBC),
Jul 15/75.

LYTHRI (Schrank), MYZUS
Prunus domestica: Vancouver, Jun 2/73.

MACROSIPHUM (Wilson),
ACYRTHOSIPHON
Amelanchier alnifolia: Summerland,
May 28/75.

Amelanchier canadensis: Vancouver (UBC),
Jun 11/75:

Amelanchier laevis: Vancouver (UBC),

Jun 5/75.

*MAGNA Hille Ris Lambers, MASONAPHIS
Composites: Lac La Hache, Jul 6/66
(Hille Ris Lambers 1974).

*MANITOBENSIS Robinson,
MACROSIPHUM
Cornus stolonifera: Vancouver (UBC),
Jun 12/74.

MAXIMA (Mason), MASONAPHIS
Rubus parviflorus: Vancouver (UBC),

Apr 3/74, Apr 18/74, Apr 22/74, Jun 18/74,
Aug 27/74.

*MODESTUM (Hottes), MYZODIUM
Pogonatum urnigerum: Vancouver (UBC),
Aug 26/74.

Polytrichum commune: Vancouver (UBC),
Aug 6/74, Aug 7/74, Aug 14/74.

Polytrichum juniperinum: Vancouver (UBC),
Mar 6/75, Jul 3/74, Jul 8/74, Jul 16/74,
Jul 23/74, Aug 2/74, Aug 7/74, Aug 9/74.

MORRISONI (Swain), MASONAPHIS
Chamaecyparis pisifera: Vancouver (UBC),
Aug 15/74.
Chamaecyparis pisifera
couver (UBC), Jul 30/74.
Chamaecyparis pisifera ‘Filifera’: Vancouver
(UBC), Aug 15/74.

‘Boulevard’: Van-

Chamaecyparis pisifera ‘Plumosa’: Van-
couver (UBC), Jul 30/74, Aug 15/74,

Aug 27/75.

Chamaecyparis pisifera ‘Squarrosa’: Van-

couver (UBC), Jul 30/74.
Cupressocyparis leylandii: Vancouver (UBC),
Aug 15/74.

Juniperus chinensis ‘Pfitzeriana’: Van-
couver (UBC), Aug 15/74.
Sequoiadendron _ giganteum: Vancouver

(UBC), Sep 4/75, Sep 11/75.

Thuja plicata: Vancouver (UBC), Aug 29/74.
NEOMEXICANA (Cockerell), APHIS

Ribes laxiflorum: Agassiz, May 11/59.

Ribes sanguineum: Vancouver (UBC),

May 16/75.
NERVATA (Gillette), WAHLGRENIELLA

Arbutus menziesii: Vancouver (UBC),

Apr 7/75, Apr 28/75.

NYMPHAEAE (Linnaeus), RHOPALOSI-
PHUM
Alisma plantago-aquatica: Vancouver

(UBC), Aug 28/74.

Elodea canadensis: Vancouver, Sep 22/74.
Prunus avium: Summerland, Oct 25/74.
Prunus domestica: Summerland, Oct 25/74.
Prunus persica: Summerland, Oct 25/74.
Prunus sp: Surrey, May 20/73.

Saururus cernuus: Vancouver (UBC),

Aug 28/74.

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), Dec. 31, 1976 61

OCCIDENTALIS (Davidson), CINARA
Abies siberica: Vancouver (UBC), Jul 10/75.

ORNATUS Laing, MYZUS

Abelia ‘Edward Goucher’: Vancouver (UBC),
Jun 24/75, Oct 24/75.

Campanula persicifolia: Vancouver, Jul
15/75, Aug 19/75.

Deutzia x rosea var carminea: Vancouver
(UBC), Jun 18/75.

Forsythia x intermedia: Vancouver (UBC),
Jun 18/75.

Gynura aurantiaca: Richmond, Nov 5/75.
Lactuca sp: Vancouver, Apr 5/58.

Lapsana communis: Vancouver, Jun 13/75.
Mentha spicata: Vancouver, Jul 23/75.

Oxalis corniculata: Vancouver, Jul 23/75.
Philadelphus lewisii var gordonianus: Van-
couver (UBC), May 22/58.

Philadelphus x virginalis: Vancouver (UBC),
Jun 18/75.

Primula alpicola ssp luna: Vancouver (UBC),
Sep 12/75.

Ranunculus occidentalis: Vancouver,

May 20/75.

Rheum rhaponticum: Vancouver, May 20/75.
Trifolium pratense: Vancouver, Sep 26/75.
Weigela ‘Eva Rathke’: Vancouver (UBC),

Jul 3/75, Sep 3/75.

OSMARONIAE (Wilson), MACROSIPHUM
Osmaronia cerasiformis: Vancouver (UBC),
Apr 30/75, Aug 29/74.

PADI (Linnaeus), RHOPALOSIPHUM
Prunus virginiana: Summerland, May 28/75.

*PALUSTRIS (Theobald), EUSCHIZAPHIS
Juncus articulatus: Vancouver (UBC),

Aug 6/74, Aug 7/74.

Juncus tenuis: Vancouver (UBC), Aug 6/74.

PARVIFLORI Hill, AMPHOROPHORA
Rubus discolor: Vancouver (UBC), Jun
12/74, Jun 25/74.

PASTINACAE (Linnaeus), CAVARIELLA
Heracleum lanatum: Vancouver, May 24/73;
Vancouver (UBC), Aug 7/75.

Salix lasiandra: Vancouver, Sep 26/75.

Salix sp: Vancouver, Jun 5/73.

PERSICAE (Sulzer), MYZUS

Callistephus chinensis: Vancouver (CDA),
Nov 3/75 (In Greenhouse).

Capsicum sp: Chilliwack, Aug 27/74.
Convolvulus sepium: Vancouver, May 15/75.
Daucus carota: Vancouver (CDA), May

23/74 (In Greenhouse).

Epilobium watsonii: Vancouver (UBC),

Aug 18/75.

Philadelphus x virginalis: Vancouver (UBC),
Jul 22/75.

Pisum sativum: Vancouver (CDA), Nov
17/75 (In Greenhouse).

Plantago major: Vancouver (UBC),

Sep 11/74.

Portulaca oleracea: Vancouver (UBC),
Sep 11/74.

Prunus persica: Summerland, Oct 25/74.
Vicia faba: Agassiz, Jul/65.

*PILICORNIS (Hartig), CINARA
In flight: Vancouver (UBC), Jun 11/75.
Tsuga heterophylla: Vancouver, Jul 14/75.

PINEA (Mordvilko), CINARA
Pinus nigra: Vancouver (UBC), Jun 23/75.
Pinus sylvestris: Vancouver (UBC),
Sep 4/75.

PINETI (Fabricius), SCHIZOLACHNUS
Pinus sylvestris: Vancouver (UBC), Sep 4/75.

*PISUM SPARTII (Koch),
ACYRTHOSIPHON
Cytisus scoparius: Vancouver (UBC),
Aug 29/74.

PLANTAGINEA (Passerini), DYSAPHIS
Malus sp: Vancouver (UBC), Jun 13/75.

POMI DeGeer, APHIS
Amelanchier canadensis: Vancouver (UBC),
Jun 11/75:
Cotoneaster bullata: Vancouver (UBC),
Jun 20/75.
Cotoneaster dammeri: Vancouver (UBC),
Jun 5/75.
Cotoneaster horizontalis: Vancouver (UBC),
Jun o/s 1d:
Cotoneaster salicifolia ‘Repens’: Vancouver
(UBC), Jun 5/75.
Crataegus douglasii: Vancouver (UBC),
Jun 5/75.
Malus ionensis: Vancouver (UBC), Jun 17/75.
Pyracantha crenulata ‘Flava’: Vancouver
(UBC), Sep 11/75.
Sorbus aucuparia: Vancouver (UBC),
Jun 18/75.

POPULIMONILIS (Riley),
PARATHECABIUS
Previously listed as THECABIUS POPULI-
MONILIS (Riley).

POPULIVENAE Fitch, PEMPHIGUS
Rumex acetosella: Richmond, Oct 6/75.

*PRAETERITA Walker, APHIS
Epilobium angustifolium: Lulu Island,
Jul 14/70.

*PRUNI Wilson & Davis, ASIPHONAPHIS
Prunus virginiana: Summerland, May 28/75.

PRUNI (Geoffroy), HYALOPTERUS
Prunus avium: Summerland, Oct 25/74.
Prunus domestica: Summerland, Oct 25/74.
Typha latifolia: Salmon Arm, Aug 18/74;
Vancouver (UBC), Aug 9/74.
*PSEUDOMORRISONI MacGillivray,
MASONAPHIS

Juniperus squamata ‘Meyeri’: Vancouver
(UBC), Sep 11/75.

62 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), Dec. 31, 1976

PSEUDOTAXIFOLIAE Palmer, CINARA
Moericke yellow pan water trap: Chilliwack,
Aug 2/67.

*PUNCTATA (Monell), MYZOCALLIS
Quercus macrocarpa: Vancouver
Jul 10/75.

Quercus prinus: Vancouver (UBC), Jun 11/75.

PUNCTIPENNIS Zetterstedt, EUCERAPHIS
Betula papyrifera var commutata: Vancouver
(UBC), Apr 18/74.

RHAMNI Clarke, MACROSIPHUM
Rhamnus_ purshiana: Vancouver
Nov 4/75.

ROSAE (Linnaeus), MACROSIPHUM
Ilex altaclarensis: Vancouver (UBC),
Jun 18/75.

Ilex glabra: Vancouver (UBC), Jun 19/75.
Ilex integra: Burnaby, Jun 9/75.

RUSSELLAE Hille Ris Lambers,
DACTYNOTUS
Anaphalis margaritacea: Vancouver (UBC),
Sep 12/75, Sep 23/75.

SAMBUCIFOLIAE Fitch, APHIS
Sambucus racemosa var arborescens:
couver (UBC), Apr 19/75, Apr 30/75,
Aug 27/74.

SANGUICEPS Richards, PTEROCOMMA
Salix scouleriana: Vancouver (UBC),
Apr 18/74, Apr 30/74, May 10/74.
Salix sp: Vancouver (UBC), Oct 23/48.

SCABROSUM Richards, AULACORTHUM
Rubus spectabilis: Vancouver (UBC),
Jun 25/74.

SCLEROSA Richards, ROEPKEA
Crataegus douglasii: Duncan, Aug 4/65
(Richards 1969).

Lathyrus nevadensis ssp lanceolatus:
Victoria, Aug 5/65 (Richards 1969).

SENSORIATA (Gillette & Bragg), ROEPKEA
Previously listed as SENSORIATA (Gillette
& Palmer) due to a typographical error.

SIPHUNCULATA Richards, PLACOAPHIS
In flight: Vancouver (UBC), Sep 23/75.
Rosa sp: Creston, Jun/55 (Richards 1961b).

SOLANI (Kaltenbach), AULACORTHUM
Aucuba japonica: Vancouver, Jun 4/74.
Clematis ‘Nelly Moser’: North Vancouver,
May 20/74.

Digitalis purpurea: Vancouver, Sep 26/75.
Heracleum lanatum: Vancouver (UBC),
Jun 9/75.

Lapsana communis: Vancouver, Jun 13/73.
Philadelphus lewisii var gordonianus:
Vancouver, Apr 20/73.

Primula juliae ‘Wanda’: Victoria, May 18/73.
Primula sp: Vancouver (CDA), Mar 9/75
(In Greenhouse).

Tilia americana: Vancouver (UBC),

Jun 11/75.

(UBC),

(UBC),

Van-

Tropaeolum majus: North Vancouver,
Jun 18/74.
Tulipa gesneriana: North Vancouver,
May 25/75.

SPIRAEAE MacGillivray, MASONAPHIS
Previously listed as SPIRAEAE (MacGilliv-
ray) due to a typographical error.

Corylus cornuta: Vancouver (UBC),
Jun 10/74, Jun 12/74.

Spiraea douglasii: Vancouver (UBC),
Jul 15/75.

*SPIRAECOLA (Patch), MASONAPHIS
Spiraea thunbergii: Vancouver (UBC),
Jun 18/75.

*SPIROTHECAE Passerini, PEMPHIGUS
Populus nigra var italica: Vancouver (UBC),
Apr 24/74, Apr 25/74, Apr 26/74, Apr 30/74,
May 24/74, Jun 13/74, Jul 5/74, Aug 13/74,
Sep 6/74, Sep 27/74, Oct 15/73, Oct 15/74,
Oct 16/74, Nov 1/74, Nov 4/74.

STANLEYI Wilson, MACROSIPHUM
Previously listed as STANLEYI (Wilson) due
to a typographical error.

Sambucus racemosa var arborescens: Van-
couver (UBC), Apr 19/75, Apr 30/75, Jun
25/74, Aug 27/74.

STAPHYLEAE (Koch), RHOPALOSIPHON-
INUS
Vinca minor: Vancouver (UBC), Jun 19/75.

TANACETARIA (Kaltenbach), MACROSI-
PHONIELLA
Tanacetum vulgare: Texas Lake, Jul 24/67.

TESTUDINACEA (Fernie), PERIPHYLLUS
Acer ginala: Vancouver (UBC), Jun 5/75.
Acer glabrum var douglasii: Vancouver
(UBC), Jun 5/75.

TILIAE (Linnaeus), EUCALLIPTERUS
Tilia americana: Vancouver (UBC),
29/75, May 16/75, Jun 11/75, Oct 3/75.
Tilia petiolaris: Vancouver (UBC), Jun 5/75,
Oct 6/75.

ULMISACCULI (Patch), COLOPHA
Agropyron repens: Laidlaw, Apr 17/74.

*VIBURNICOLA (Gillette), NEOCERUR-
APHIS
Viburnum opulus: Vancouver, Apr 22/73.

*WAHNAGA Hottes, MASONAPHIS
In flight: Vancouver (UBC), Sep 23/75.

WALSHII (Monell), MYZOCALLIS
Quercus rubra: Vancouver, Aug 30/74; Van-
couver (UBC), Aug 29/74.

XYLOSTEI (DeGeer), STAGONA
Previously listed as PROCIPHILUS
XYLOSTEI (DeGeer).

Apr

*Aphid species not in the previous lists.

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976 63

References

Forbes, A. R., B. D. Frazer, and H. R. MacCarthy. 1973. The aphids (Homoptera: Aphididae) of
British Columbia. 1. A basic taxonomic list. J. ent. Soc. Brit. Columbia 70: 43-57.

Forbes, A. R., B. D. Frazer, and Cho-Kai Chan. 1974. The aphids (Homoptera: Aphididae) of
British Columbia. 3. Additions and corrections. J. ent. Soc. Brit. Columbia 71: 43-49.

Hille Ris Lambers, D. 1974. On American aphids, with descriptions of a new genus and some new.
species (Homoptera, Aphididae). Tijdschrift voor Entomologie 117: 103-155.

Raworth, D. A., and B. D. Frazer. 1976. Compilation of taxonomic catalogues by computer.

J. ent. Soc. Brit. Columbia 73:

Richards, W. R. 1961la. North American Bornerina Bramstedt and Betulaphis Glendenning
(Homoptera: Aphididae). Canad. Ent. 93(6):486-494.

1961b. New genera and species of rose-infesting aphids (Homoptera:

Aphididae). Canad. Ent. 93(8): 622-625.

. 1969. A review of the holarctic genus Roepkea with descriptions of four new
nearctic species (Homoptera: Aphididae). Canad. Ent. 101 (11): 1121-1162.

COMPILATION OF TAXONOMIC CATALOGUES BY COMPUTER
D. A. RAWORTH ANDB. D. FRAZER

Research Station, Agriculture Canada
Vancouver, British Columbia V6T 1X2

ABSTRACT

The advantages of using a computer are examined for storing, updating,
and cross indexing taxonomic collection data in working and published lists.

Records of collections of animals and plants
for taxonomic purposes or for compilations of
more general lists of fauna and flora are
typically and unavoidably voluminous. Dif-
ficulty occurs in manually updating, cross in-
dexing and listing data about each collection
easily and quickly. However, the data are
usually regular, in that information for every
collection may be split into several logical and
uniform divisions. For example, collection data
consistently include taxonomic identification,
location of the sample, date, collector, and
sometimes a description of the sample and
habitat. This regularity suits the data ad-
mirably to computer storage and manipulation.
The advantage of using a computer is mainly in
the speed with which it can extract, arrange
and print information. The time saved is ap-
preciable as the data base becomes larger. This
paper discusses the use of the computer for
maintaining and updating the various lists
associated with a collection of aphids from
British Columbia.

The aphidologists of our research group
have accumulated a data base of more than
1500 collections during the past 20 years. In-
formation is recorded on cards (Fig. 1) at the
time a collection is made and these cards are in-
dexed by plant host species. When an aphid is
identified these data are also indexed
alphabetically by aphid species. About 150

collections are added each year. The task of
identifying aphids is made easier by using lists
of previously collected aphids and host plants
ordered in various ways (1, 2, 3), so that much
time has been spent maintaining cross indices
by hand.

Computer programming is a time con-
suming and often costly procedure. Most com-
puting centers, however, maintain a library of
those ‘canned’ programs most often needed by
computer users. One such program called “The
UBC Report Generator’ (RG), (4) was suited to
our needs. The following is a brief description of
how RG was used.

RG requires that all collections have the
same divisions or fields of data, and that these
fields be in a constant order. We ordered our
data on three data cards per collection: by
aphid genus, species and authority on the first;
by host plant family, common name, genus,
species and class code on the second; and by
location of sample, month number, month, day,
year, collector’s name and lot number on the
third. These fields are separated by commas.
Since RG is extremely flexible this is only one
of a number of ways in which the data can be
organized. The data were then punched on com-
puter cards (Fig. 2) and the card images were
stored on magnetic tape for economical com-
puter operations.

64 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976

Aids

V/,

ee

Li

gis

Fig. 1. A completed collection card.

In order to obtain lists, we ‘ran’ RG with
the data, a description of how the data were set
up and a series of commands describing what
items to extract and how to order and print
them (Fig. 3). Many other possibilities exist.

In many instances, field contents may be
duplicated from collection to collection and
when ordered, appear redundant (Fig. 3a).
Although RG does not have the facility to
reduce redundancy, it does allow the use of
computer language subroutines which can be
written to handle the problem. Subroutines
were written in FORTRAN IV, to eliminate
redundancy (Fig 4) and to provide appropriate
punctuation.

The printing capability of the computer is
far greater than that indicated by figures 3 and
4 because it has all the necessary typewriter
characters and is much faster. Since
publishable manuscripts were desirable in ad-
dition to working lists, a computer program
was written to convert the normal upper case
computer card characters to appropriate upper
and lower case characters (Fig. 5).

Although RG is a complex program capable
of many tasks it is remarkably easy to use,

even for those not familiar with computers.
Costs are minimal, but of course vary with the
quantity and complexity of the lists.
Preparation of a list of 1500 collections
organized as illustrated (Fig. 3-5) cost between
$5.00 and $15.00. The time required is as little
as three minutes for the finished product. By
far the most difficult and time consuming task
is keypunching the original data, but this is
done only once.

In conclusion, computer capabilities in
taxonomy are limited only by need, time,
money and imagination. We hope that greater
use will be made of computers for facilitating
the manipulation of animal and plant collection
data. Their use for this purpose promotes bet-
ter and more efficient use of the data and frees
research and support staff for more interesting
duties.

ACKNOWLEDGEMENTS
We thank Dr. A. R. Forbes and Mr. Cho-Kai
Chan who provided the data, the staff of the
UBC Computing Centre, in particular Rita
Cockle, who gave information and advice and
Mr. S. W. MacDiarmid for the photography.

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), Dec. 31, 1976 65

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Fig. 2. The collection data on computer cards.

Cle PINOPSIDA (CONIFERS)
Fe CUPRESSACEAE CHAMAECYPARIS PISTFERA *PLUMOSA®
MASONAPHIS MORRISONT
Cle MAGNOLIOPSIDA (FLOWERING PLANTS =~ DICOTYLEDONS)
F. CAPRIFOLIACEAF VIBURNUM TRILOBUM
APHIS FABAE
Cle MAGNOLIOPSIDA (FLOWERING PLANTS - DICOTYLEDONS)
Fe CAPRIFOLIACEAE VIBURNUM TRILOBUM
APHTS FABAE
Cle MAGNOLIOPSIDA (FLOWERING PLANTS - DICOTYLFEDONS)
Fe ROSACEAE PRUNUS DOMESTICA
HYALCPTERUS PRUNT
Cle LILIOPSIOA (FLOWERING PLANTS -— MONOCOTYLEDONS)
Fe TYPHACEAE TYPHA LATIFOLIA
HYALCPTERUS PRUNT
Cle LILIGPOSIDA (FLOWERING PLANTS - MONOCOTYLEDONS)
Fe TYPHACEAE TYPHA LATIFOLIA
HYALCPTERUS PRUNI

Fig. 3a. All collections of figure 2 extracted and ordered by plant class, family, genus, and species;
aphid genus, and species.

66

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEC. 31, 1976

FABAE SCOPOLI APHIS

VIBURNUM TRILOBUM VANCOUVER (UBC) JUL3/75
FABAE SCOPOLI APHIS

VIBURNUM TRILOBUM VANCOUVER (UBC) SEP3/75
MORRISONI (SWAIN) MASONAPHIS

CHAMAEC YPARIS PISIFERA *PLUMOSA® VANCOUVER (UBC) JUL30/74
PRUNI {(GEQFFROY) HYALOPTERUS

PRUNUS DOMESTICA SUMMERLAND OCT25/74
PRUNI {GEOFFROY) HYALOPTERUS

TYPHA LATIFOLIA SALMON ARM AUGLB/74
PRUNI (GEOFFROY) HYALOPTERUS

TYPHA LATIFOLIA VANCOUVER (UBC) AUG9/74

Fig. 3b. All collections of figure 2 extracted and ordered by aphid species, authority, and genus;

plant genus, and species; location, month number, day, and year.

APHIS FABAE SCOPOLI
VIBURNUM TRILOBUM JUL3/75
HYALOPTERUS PRUNI (GEOFFROY)
TYPHA LATIFCLIA AUG9S/74&

. All collections of figure 2 extracted where plant class code was ‘QA’ or ‘QB’, location

contained ‘Vancouver’, and month number was less than 9.

Cle PINOPSIDA (CONIFERS)
Fe CUPRESSACEAS |
CHAMAECYPARIS PISTFERA *PLUMOSAS
MASONAPHIS MORRISONI
Cle MAGNOLIOPSIDA (FLOWERING PLANTS — DICOTYLEDONS)
Fe CAPRIFOLIACEAE
VIBURNUM TRILOBUM
APHIS FABAE
Fe ROSACEAF
PRUNUS DOMESTICA
HYALOPTERUS PRUNT
Cle LILIOPSIDA (FLOWERING PLANTS - MONOCOTYLENONS) -
Fe. TYPHACEAF
TYPHA LATTFOLIA -
HYALOPTERUS PUNT

Fig. 4. Redundancy of figure 3a eliminated.

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976 67

aw
®
FABAE Scopoli, APHIS
¢ Viburnum trilobum: Vancouver (UBC), Jul3/75, Sep3/75.
MORRISONI (Swain), MASONAPHIS
¥ Chamaecyparis pisifera 'Plumgsa': Vancouver (UBC), Ju130/74.
PRUNI (Geoffroy), HYALOPTERUS
@ Prunus domestica: Summerland, Oct25/74.
Typha latifolia: Salmon Arm, Aug18/74; Vancouver (UBC), Aug9/74,
e
®

Fig. 5. Figure 3b in publishable form.

References
Forbes, A. R., B. D. Frazer and H. R. MacCarthy. 1973. The Aphids (Homoptera: Aphididae) of
British Columbia. 1. A Basic Taxonomic List. J. Ent. Soc. Brit. Col. 70:43-57.
Forbes, A. R. and B. D. Frazer. 1973. The Aphids (Homoptera: Aphididae) of British Columbia.
2. A Host Plant Catalogue. J. Ent. Soc. Brit. Col. 70:58-68.
Forbes, A. R., B. D. Frazer and Cho-Kai Chan. 1974. The Aphids (Homoptera: Aphididae) of
British Columbia. 3. Additions and Corrections. J. Ent. Soc. Brit. Col. 71:43-49.

Miller, A.

1975. The UBC Report Generator. Computing Center, the University of British

Columbia, Vancouver, B.C., Canada V6T 1W5.

BOOK REVIEW

Mamaev, B. M. 1974. Evolution of gall forming
insects—gall midges (English Edition). Trans-
lated by A. Crozy, edited by K. M. Harris.
Published by The British Library, Lending
Division, printed by W. S. Maney Ltd., Leeds,
England, 317 pp. 79 figs. Size 6’ x 812" (15.5¢ x
22c). Paper cover. Price L 8.50, + $15.00.
(Translation of Russian Edition, published by
‘Nauka’’, Leningrad, 1968).

This book is a monograph of the family
Cecidomyiidae that focuses on the origins, the
lines and the patterns of evolution. It defines
the family, the subfamilies, the tribes and sub-
tribes in terms of the morphology, anatomy and
ecology of all stages, but it contains no taxo-
nomic keys. The author’s primary purpose is
to outline the evolutionary development of gall
midges, and from this, to construct a logical
classification. Thus, the classification adopted
in the first chapter is, in effect, the practical
outcome of the contents of the remaining seven
chapters. The book is the culmination of 15
years work, beginning in 1951, on the native
gall midge fauna of the European U.S.S.R.,
the Caucasus, Central Asia and the Far East.
The collation of collections from different habi-
tats (soil, litter, wood and living plant tissues)
from these geographically distant and ecologi-
cally distinct areas (forests, steppes, deserts
and mountains) provide the factual bases for
the theoretical constructions developed.

Dr. Mamaev is well qualified to undertake
such a project. He obtained his Ph.D under
Prof. E. S. Smirnov, Head, Department of
Entomology, Moscow State University, about
1951, and then went to work at the Institute
of Evolutionary Morphology and Ecology of
Animals, (Laboratory of Soil Zoology) Soviet
Academy of Sciences in Moscow. Since then
he has been a prolific researcher (author or co-
author of 38 papers cited in the book),
especially on Cecidomyiidae. All his work has
been based on a multidisciplinary approach
and most of his findings reflect a thorough-
ness and a soundness rarely encountered. His
book is based largely on his own findings,
coupled with first-hand information from col-
leagues with similar interests. Thus his book
is built on a solid foundation of personal inves-
tigations and knowledge, and is much more
than a synthesis of previously published data.

Part one, consisting of four chapters, deals
primarily with the morphological aspects of the
evolution of gall midges. Chapter one consists
of diagnoses of the family, subfamilies, tribes
and the subtribes; it also provides a modern
classification of the family breaking it into two
subfamilies: the Lestremiinae with three tribes,
Lestremiini, Moehniini (since eliminated be-
cause the only known species belongs to the
Sciaridae), and Micromyiini, and the Cedico-
myiinae with six tribes, Heteropezini, Por-
ricondylini, Oligotrophini, Lasiopterini, Ceci-

68

domyiini and Asphondyliini. Chapter two
describes the evolution of the larvae from the
standpoints of morpho-ecological types, adapt-
ive changes in the integument, the head struct-
ures and the digestive systems. Chapter three
deals with the evolution of the adults in a
similar manner but with special emphasis on
development of winglessness, changes in sense
organs, and the form of the male and female
terminalia. Chapter four is an analysis of the
occurrence patterns of morphological charac-
ters in larvae and adults, ending in a dendro-
gram showing the ‘phylogenetic links of the
major taxonomic groups of gall midges.” Of
special interest is a discussion on the exchange
of secondary sexual characters between males
and females, e.g., feminization of antennae in
males, and the significance of such phenomena
in classification. Unfortunately the dendrogram
(Fig. 45) summarizing the ideas of this chapter
is poorly organized. It shows the subfamily
Cecidomyiidae as a monophyletic group arising
from a single subtribe (Catochina) of the Lest-
remiinae. This, in effect, makes the Cecido-
myiinae a sister-group of the subtribe Cato-
china and makes the subfamily Lestremiinae
a paraphyletic group. In the text, however,
and in a subsequent phylogenetic chart (Fig.
79) the Cecidomyiinae are correctly treated as
a sister-group of the Lestremiinae, i.e., arising
from the common ancestor of all Cecidomyiidae.

The second half of the book also contains
four chapters and deals mainly with the ecologi-
cal aspects of the evolution of the gall midges.
Chapter five considers the ecological pre-
requisites for proliferation of gall midges—
adaptations for expansion into different hosts
and geographic areas, and adaptations for in-
tensifying the multiplication and_ survival
of species. Chapter six deals with the ecological
pathways leading to mycetophagy, phyto-
phagy and gall formation; it also includes
discussions on gall midges as plant parasites
and on the importance of flowers in their evo-
lution. Chapter seven treats special aspects of
gall fly speciation and gall formation in plants;
one of the main points made is that host data
and the forms of the galls are not always reli-
able criteria for species identification. Chapter
eight reviews the paleontological data relating
to gall midges, and discusses the main stages
of evolution of the family in relation to geo-
logical ages, ecological backgrounds and the
evolution of plants. The author concludes that
the Cecidomyiidae are a sister-group of the
Mycetophilidae and he provides a phylogenetic
chart showing the evolution of all the tribes
within the family. The final pages include an
appendix outlining techniques for collecting and

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976

studying gall midges, lists of references in
Roman and Cyrillic alphabets and an index
of the Latin names of insects referred to in the
text.

The book fulfills a real need for this large
and difficult group, possibly the largest family
of Diptera. The author has managed success-
fully to analyse and synthesize an immense
amount of information from the whole spec-
trum of biosystematics and to construct a
classification that appears to be both practical
and in harmony with the evolutionary patterns
of the group. He has introduced a wealth of new
facts and ideas and has provided a very real
addition to our knowledge on almost all
aspects of the biology and systematics of these
flies. No other book covers the subject so
thoroughly or so well. As the author himself
states, however, refinements and improvements
will appear as further progress is made on this
and related families. For example, the genus
Moehnia (known from females only of one
species) is now known to be an aberrant mem-
ber of the Sciaridae, thereby eliminating one
of the tribes of the Lestrimiinae. Such develop-
ments are to be expected and do not reduce the
overall value of the book.

This edition is a translation, and the trans-
lator and the editor have wisely adhered to a
policy of exactly portraying the thoughts of the
author rather than producing smooth, beautiful
English. This results in a style that is some-
times heavy and awkward, but in general
Messrs. Crozy and Harris are to be compli-
mented for an easily readable rendition. The
author’s method of providing separate conclu-
sions at the end of each chapter has resulted
in a certain amount of repetition, but this is
not a bad fault. The book itself was printed by
photographic means from typewritten pages,
and it has the general appearance of a xeroxed
thesis. The right margin of each page is very
uneven and in a few instances (pp. 22, 134)
the reproduction is poor; the half tone photo-
graphs (about half the figures) also suffered
as a result of this type of reproduction. The
paper is of good quality, but the bindng is
extremely poor; many pages of my copy have
become detached from the spine of the book.

There can be no doublt that his work repre-
sents a very significant step forward in our
knowledge of gall midges, and that it will be a
basic reference for many years. Anyone who
has any interest in the family should have a
copy.

J. F. McAlpine,

Biosystematics Research Institute,
Agriculture Canada,

Ottawa, Ontario, K1A OC6.

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976 69

NOTICE TO CONTRIBUTORS

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70

J. ENTOMOL. Soc. Brit. COLUMBIA 73 (1976), DEc. 31, 1976

cal

72

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), Dec. 31, 1976

a.

ey

. os % ee ie

' ENTOMOLOGICAL
_ ~SOCIETY of

Issued December 31, 1977

ae ECONOMIC

; CARTY—Pest management: four years experience in a
BOMPMIEEM ANG oe ee ete eee etree teeter eeseesee
& EVERSON—Phytoseiulus persimilis (Acarina: Phytoseiidae) for
of two-spotted mites in a commercial greenhouse ...............2...225 7
& TONKS—A method for rearing the predaceous mite,
Jseiulus persimilis (Acarina: Phytoseiidae) .............0. cece cece e sees 8

GENERAL

Pe cue BO es te a ee Ee eee 10

R & FINLAYSON—Parasites of the larch casebearer, Coleophora
(Lepidoptera: Coleophoridae) in the West Kootenay area,
Sh e's Srey dia alta Wie ab eicsiw bd cye k ce eee vee 1G

& OLSEN—Feeding potential of predators of Myzus persicae ............23

AKRE—Morphology of alimentary and reproductive tracts of the
ent bot fly, Cuterebra tenebrosa (Diptera: Cuterebridae) ...................27

ve , SNYDER & COLETTI—Insects collected from an alpine-subalpine
TE Ae Na fate a ee

TAXONOMIC

LTON—A new Clastoptera from sagebrush

Seeuota, Homoptera: Cercopidac) 6... .0 06. ee ee ee we le eee oe BS
I ea tee ya We Gaus y fin Seek a dice yn s vie oo su bw ee 9, 26, 31,41

Re a coke eco e s 42

JOURNAL

of the

ENTOMOLOGICAL
SOCIETY of
BRITISH COLUMBIA

Issued December 31, 1977

ECONOMIC
MADSEN & CARTY—Pest management: four years experience in a
commercial orchard
TONKS & EVERSON—Phytoseiulus persimilis (Acarina: Phytoseiidae) for
control of two-spotted mites in a commercial greenhouse
THEAKER & TONKS—A method for rearing the predaceous mite,
Phytoseiulus persimilis (Acarina: Phytoseiidae)

GENERAL

MILLER & FINLAYSON—Distribution of Coleophora laricella (Lepidoptera:

Coleophoridae) and its major parasites in the crowns of western larch

in British Columbia
MILLER & FINLAYSON—Parasites of the larch casebearer, Coleophora

laricella (Lepidoptera: Coleophoridae) in the West Kootenay area,

British Columbia
TAMAKI & OLSEN—Feeding potential of predators of Myzus persicae ............ 23
BAIRD & AKRE—Morphology of alimentary and reproductive tracts of the

rodent bot fly, Cuterebra tenebrosa (Diptera: Cuterebridae)
DYER & HALL—Effect of anti-aggregative pheremones 3,2-MCH and

trans-verbenol on Dendroctonus rufipennis attacks on spruce stumps ...........32
HARLING, SNYDER & COLETTI—Insects collected from an alpine-subalpine

region in S. BH. British Columbia... 0... 00 cc ccc cece cece ct cence ccc c sc cense D4
VANDERSAR—Overwintering survival of Pissodes strobi (Peck)

(Coleoptera: Curculionidae) in sitka spruce leaders .............0 ccc cece eeeee od

TAXONOMIC
HAMILTON—A new Clastoptera from sagebrush
(Rhynchota: Homoptera: Cercopidae)

SCIENTIFIC NOTES

J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977

Directors of the Entomological Society of
British Columbia for 1977-1978

President
A. L. TURNBULL

Simon Fraser University
Burnaby

President-Elect
P. BELTON

Simon Fraser University
Burnaby

Past-President

H. S. GERBER
B.C. Min. of Agriculture
Cloverdale

Secretary-Treasurer

B. W. FRASER
6660 N. W. Marine Drive,
Vancouver, B.C. V6T 1X2

Editorial Committee
H. R. MacCARTHY

Vancouver

J. CORNER

Vernon

Directors
R. COSTELLO (2nd) N. V. TONKS (2nd) _ G. Gillespie (1st)
A. R. FORBES (1st) R. ELLIOTT (1st)

Regional Director of National Society
J.P. M. MACKAUER

Simon Fraser University, Burnaby

J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977 3

PEST MANAGEMENT: FOUR YEARS EXPERIENCE
IN A COMMERCIAL APPLE ORCHARD

H. F. MADSEN AND B. E. CARTY:

Research Station, Agriculture Canada,
Summerland, British Columbia

ABSTRACT

Pest management in a 12 ha apple orchard from 1973 to 1976 resulted in
a 50 percent reduction in the number of sprays that are normally applied to
control insects and mites. Codling moth, Laspeyresia pomonella (L.), popula-
tions were monitored by sex pheromone traps and populations of other
insects and mites were assessed by specific sampling techniques. Leafrollers
were the most difficult pests to control and fruit injury was 1.5 to 2.0 per-
cent in 3 of the 4 years. Mites were held below treatment levels by the
predator, Typhlodromus occidentalis Nesbitt, except for the apple rust mite,
Aculus schlechtendali (Nalepa) which required chemical control.

INTRODUCTION

Six commercial apple orchards were pest
managed from 1973 to 1976 in order to validate
sampling techniques and economic injury levels
for major apple pests. This paper examines
the data from one of these orchards over a 4-
year period. Pest intensity varies from orchard
to orchard, and date from one site is not
completely representative of all areas.
However, it does illustrate the efficiency of
procedures and the value of pest management
as a method of pest control.

METHODS

The pest managed orchard was located in
East Kelowna, B.C. in the heart of an apple
and cherry growing area. It was 12 ha in size
and planted to 4 apple cultivars, McIntosh,
Spartan, Red Delicious and Golden Delicious.
The McIntosh and Spartan trees were in solid
blocks and the Red Delicious were interplanted
with Golden Delicious. All trees were standard
plantings with variable planting distances.
Previous to 1973, the orchard was sprayed
routinely following recommendations in the
B.C. Tree Fruit Production Guide and received
ca. 7 applications each season.

The following pests were monitored during
the 4-year study: European fruit scale, Quadra-
spidiotus ostreaeformis (Curtis); San Jose
scale, Quadraspidiotus perniciosus (Comstock):
fruittree leafroller, Archips argyrospilus
(Walker); European leafroller, Archips rosanus
(Linnaeus); codling moth, Laspeyresia
pomonella (Linnaeus); western flower thrips,
Frankliniella occidentalis (Pergande); the
mirid Campylomma verbasci (Meyer): white
apple leafhopper, Typhlocyba pomaria McAtee;
eyespotted budmoth, Spilonota ocellana (Denis
& Schiffermuller); apple aphid, Aphis pomi
DeGeer; European red mite, Panonychus ulmi
(Koch); McDaniel spider mite, Tetranychus

‘Contribution No. 458, Research Station, Summerland.

mcdanieli McGregor; and apple rust mite,
Aculus schlenchtendali (Nalepa).

Sampling methods and economic injury
thresholds for the above pests have been
described by Madsen et al. (1975). A few
modifications in sampling methods and a few
changes in economic injury thresholds were
made after the above paper was prepared. The
treatment level for fruittree leafroller was
reduced from 10 larvae per 100 leaf clusters to
5 because injury was 1 to 2 percent when the
treatment level was 10.

We devised a new method of assessing
thrips populations. A sample of blossom
clusters was placed in a Berlese funnel and left
there for 6 hours. As the blossoms wilted, the
thrips moved down and were captured in a jar
of alcohol at the base of the funnel. This
method was quicker and more accurate than
the previously used extractor.

The treatment level for Campylomma ver-
basci was reduced from 5 nymphs per limb
tap sample to 2. Although C. verbasci was not
a problem in the orchard described in this
paper, evidence from other orchards indicated
that a level of 5 per limb tap resulted in ca.
3 to 4 percent fruit injury.

Although 2 species of leafrollers were
present in the orchard, their seasonal history
and behavior is similar and they cause the same
type of damage to apples (Madsen et al. 1976).
Therefore, all fruit with leafroller injury was
placed in a single category.

The effectiveness of the program was
assessed by harvest samples for insects that
attack fruit directly. A total of 250 apples per
bin were examined while the fruit was being
picked and fruit injury by the various pests
was recorded. We sampled a minimum of 3 of
the total bins picked for each apple cultivar.
Pests that attack leaves and do not directly
affect fruit were assessed by rating leaf injury
if populations exceeded the treatment level.

4 J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977

RESULTS AND DISCUSSION

Codling moth is the key pest in an apple
management program because chemical control
directed against this insect affects other pests
as well as natural enemies. The data on codling
moth monitoring in this orchard during 1973
and 1974 have been discussed by Vakenti and
Madsen (1976). In 1973, sex pheromone traps
indicated low codling moth populations within
the orchard, but high numbers in neighboring
orchards. No sprays were applied and the per-
cent injured fruit at harvest was only 0.1 (Table
1). We have calculated that a codling moth
infestation of 0.5 can be tolerated by orchard-
ists and does not justify the cost of a spray
application (Vakenti and Madsen 1976). In
1974, trap captures indicated a need for treat-
ment on 3 occasions, but the moth numbers
were only slightly above the treatment level of
2 per trap. We suggested chemical control but
the orchardist chose not to apply a spray. The
codling moth injury at harvest was 0.7 percent
which indicated at least one spray would have
been justified.

Fig. 1 illustrates the codling moth captures
for 1975 and 1976. The traps captured an
average of over 4 per trap in early June of 1975
and a codling moth spray was applied a week
later. No further sprays were applied although
the moth capture was slightly above treatment
level the first week of July. In 1976, the treat-
ment level was exceeded during the week of
July 12, but over 70 percent of the moths were
captured in a single block of Red and Golden

Delicious trees. We suggested that treatment
be limited to this area which was ca. 3 of the
total orchard. A single application was applied
to this block and was the only codling moth
spray the orchard received. Fruit injury by
codling moth was well below the acceptable
level of 0.5 percent in both years. During the
4-year period, only 13 sprays were applied for
codling moth control in contrast to a calendar
based program which would have required a
minimum of 8 treatments.

Leafrollers required treatment in all 4 years,
but control from 1973 to 1975 was not as effec-
tive as expected. Diazinon was used until 1975
when there was evidence of tolerance by leaf-
rollers to this pesticide from orchards in the
same general area (Madsen and Carty 1977). In
1976, azinphosmethyl was used instead of
diazinon, and fruit injury was reduced by ca.
90 percent from the previous year.

Injury by eyespotted budmoth was negli-
gible and noted only in 1975 and 1976. Thrips
injury, represented by pansy spot on McIntosh
and Spartan cultivars, was variable and our
earlier sampling method did not detect popula-
tions that caused 2 percent injury in 1973. The
population when sampled by the Berlese funnel
method indicated a treatment level in 1975,
but the grower chose not to spray. It is doubt-
ful if a spray would have been justified since
fruit injury was less than 1 percent.

Campylomma verbasci was not present in
sufficient numbers to be of concern in this
orchard. White apple leafhopper populations

Table 1. Summary of pest management — Fitzgerald Orchard, Kelowna, 1973-1976.

Number of sprays applied, percent fruit injury

and degree of foliage injury

mee 1973 1974 1975 1976
S S I S I S I
Codling moth! 0 0 07 1 0.2 4 Onl
Fruittree leafroller and 1 2.0 1 5 iL 1.6 1, 02
European leafroller'

Eyespotted budmoth! 0 0.0 0 0.0 0 0.1 0 0.1
Thrips! 0 ZA 0 0.0 0 0.8 0 0.0
Campylomma verbasci’ 0 0.0 0 0.1 0 0.0 0 0.1
San Jose scale! 0 0.0 0 0.0 0 0.0 0 0.0
European fruit scale’ 0 0.0 0 0.0 0 0.0 0 0.0
White apple leafhopper? 0 0 nil 0 nil 1 nil
Apple aphid? 0 O nil 0 nil 0 nil
European red mite’ 1 1 nil Vp nil 1 nil
McDaniel spider mite? 0 0 nil 0 nil 0 nil
Apple rust mite? 1 i nil VY, nil 0 nil

‘damage assessed by fruit injury.

*damage assessed by leaf injury.

3+= slight damage, no effect on Apple quality.
Abbreviations: S=sprays, I=injury.

a

J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977 5

CODLING MOTH PHEROMONE TRAP CAPTURES
FITZGERALD ORCHARD EAST KELOWNA

1975

30 co «OINSIDE

mm OUTSIDE

15

10

5

: TH il
7 = = ; Ba = i | i fi] | _
= pO. | Ge SO) 14, 8. oe Ge
a MAY JUNE JULY AUG. SEPT.
2
ag
Lu
Qa
ee 1976
5 [= _ INSIDE
= mmm =OUTSIDE

: |

10

5

3 Ty, oa 14 28 12 26 9 23 6 20
MAY JUNE SEY AUG. SEPT:
Fig. 1. Codling moth pheromone trap captures 1975-1976.

Arrows indicate date of spraying. Unbroken arrow=entire orchard sprayed, broken arrow="
of orchard sprayed.

6 J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977

were below treatment levels from 1973 to 1975,
but a spray was required in 1976. Apple aphid
was present on young trees in all 4 years, but
colonies were restricted to terminal growth and
populations did not reach treatment level.

Mites were not a problem in the orchard
during the 4-year experiment except for apple
rust mite. The principal mite predator in
British Columbia orchards, Typhlodromus
occidentalis Nesbitt, increased during the first
year of pest management and there was an
excellent ratio of predators to phytophagous
mites during the subsequent 3 years. The
sprays in Table 1 for European red mite control
were delayed dormant oil treatments directed
against overwintered eggs. Downing and
Arrand (1976) stated that a delayed dormant
oil spray is often necessary to ensure that
integrated mite control programs will be
successful. Apple rust mite increased to treat-
ment level in 1973 and 1974 and light foliage
injury occurred in 1973 although a spray was
applied. In 1975, one block of Red Delicious
trees required a spray for apple rust mite
control and no leaf injury was detected.

No San Jose scale or European fruit scale
was encountered in any of the harvest samples.
European fruit scale is prevalent in other

orchards in this area and packinghouses have
advised growers to spray routinely. Our
management techniques did not indicate a need
to spray for this pest, but the dormant oil
spray used for European red mite eggs
probably had an effect on any scales that were
present.

Over the 4-year period, 14 applications were
made for pest control which is a 50 percent
reduction over a calendar based spray program.
On the whole, results in other pest managed
orchards were similar and the number of sprays
necessary to obtain control was reduced by 35
to 50 percent. The cost of an advisory program
has been calculated as $50 per ha (Haley 1976).
To apply a single spray of azinphosmethyl
for codling moth or leafroller control costs ca.
$25 per ha for the material alone. It is evident
that the cost of an advisory program would be
realized if the yearly spray program were
reduced by 2 applications. Another advantage
of pest management which has seldom been
mentioned is improved control when it is
necessary to spray. Timing of sprays is more
accurately based upon samples rather than on
calendar dates or phenological data used in
production guides.

References
Downing, R. S. and J. C. Arrand. 1976. Integrated control of orchard mites on apple in British

Columbia. Can. Ent. 108. 77-81.

Haley, Sue. 1976. Apple pest management in the North Okanagan Valley, British Columbia: A
feasibility study. M.A. Thesis, Simon Fraser University, Burnaby, B.C. 1-48.

Madsen, H. F., F. E. Peters and J. M. Vakenti. 1975. Pest management: Experience in six British
Columbia apple orchards. Can. Ent. 107: 873-877.

Madsen, H. F., and F. E. Peters. 1976. Pest management: Monitoring populations of Archips
argyrospilus and Archips rosanus (Lepidoptera: Tortricidae) with sex pheromone traps.

Ibid 108: 1281-1284.

Madsen, H. F. and B. E. Carty. 1977. Fruittree leafroller (Lepidoptera: Tortricidae): Control of a
population tolerant to diazinon. J. Econ. Ent. (in press).

Vakenti, J. M. and H. F. Madsen. 1976. Codling moth (Lepidoptera: Olethreutidae): Monitoring
populations in apple orchards with sex pheromone traps. Can. Ent. 108: 433-438.

J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), Dec. 31, 1977 7

PHYTOSEIULUS PERSIMILIS (ACARINA: PHYTOSEIIDAE)
FOR CONTROL OF TWO-SPOTTED MITES
IN A COMMERCIAL GREENHOUSE?

N. V. TONKS AND P. EVERSON?

Research Station, Agriculture Canada
Sidney, British Columbia

ABSTRACT

Natural infestations of the twospotted spider mite were controlled on
greenhouse cucumber by early releases of the predatory mite, Phytoseiulus
persimilis Athias-Henriot. Later sporadic mite outbreaks severely damaged
some plants and required frequent surveys and repeated predator releases
in the greenhouse. However, no mite sprays were required and crop yield

was Satisfactory.

INTRODUCTION

Chemical control of the twospotted spider
mite, Tetranychus urticae Koch, on greenhouse
cucumbers is becoming increasingly difficult
in British Columbia. A number of reports have
been published on the use of the predaceous
mite, Phytoseiulus persimilis Athias-Henriot,
for control of spider mites on greenhouse
cucumbers (Chant 1961; Gould 1970, 1971;
Scopes and Parr 1971; Anonymous 1972). This
paper reports the results of a preliminary trial
in British Columbia using P. persimilis for
control of the twospotted spider mite on
cucumber in a commercial greenhouse.

METHODS

A commercial greenhouse containing 1300
parthenocarpic cucumber plants on 12,500
sq. ft. (0.12 hectare) was examined on March 24
for infestations of twospotted spider mites.
Fifty-nine infested plants were tagged and 400
predator mites released among them. Predators
were distributed by tapping 2 to 5 specimens
from a glass vial onto a cucumber leaf on each
infested plant. Five leaves, on each tagged,
infested plant were then examined periodically
for host and predator mites.

‘Contribution No.
Canada, Stidney, B.C.

236, Research Station, Agriculture

*Present address: Department of Biology, University of
Victoria, B.C.

TABLE 1. Percentage of leaves with T. urticae,

Tagged plants received no further preda-
tors, but 2200 were distributed throughout the
remainder of the planting on April 1, and 2400
on June 11. An additional 1600 predators were
used to combat localized outbreaks of mites
during April and May.

RESULTS AND DISCUSSION

Table 1 shows that twospotted spider mites
on tagged, infested plants were eliminated
by mid-May, about 55 days after predator mites
were released. However, sporadic localized out-
breaks of mites occurred in the planting during
May and part of June. Some plants were
severely damaged, but losses were not serious
in relation to the total planting. Predators
were abundant throughout the planting by
June 21, and no further mite outbreaks
occurred. Both host and predator mites had
disappeared from all plants by mid-July. There
was no recurrence of twospotted spider mites
before the plants were removed in early
August.

The introduction of red spider mites in a
planting before releasing predators has been
recommended in England to establish a
predictable predator-prey interaction
(Anonymous 1972). In our trials, predators
were released in naturally occurring mite
infestations. Plants with well-established
infestations almost invariably suffered severe
damage before the predators achieved control.

and T. urticae plus P. persimilis, following the

release of predatory mites. A total of 295 leaves were examined on each sampling date.

Days after
Predator Mite Release

% Leaves
with T. urticae

% Leaves
with T. urticae
and P. persimilis

22 38
43 ig
55 1

fel

68
88
100

nil

8 J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977

In addition, sporadic outbreaks of mites
required frequent monitoring of the planting
and repeated releases of predators. Neverthe-
less, we feel that the trial was successful.
Economic control of mites was achieved when
predators were released early in the develop-
ment of mite infestations. No mite sprays were

required in the test planting, and cucumber
yields were satisfactory throughout a normal
cropping period. This contrasted with condi-
tions in the same greenhouse during the
previous season, when plant damage from
mites and frequent acaricide applications
shortened the cropping period by 3 to 4 weeks.

References
Anonymous. 1972. The biological control of cucumber pests. Growers Bull. No. 1, Glasshouse
Crops Research Institute, Littlehampton, Sussex.
Chant, D. A. 1961. An experiment on the biological control of Tetranychus telarius L. in a green-
house using Phytoseiulus persimilis A.H. Canad. Ent. 93: 437-443.

Gould, H. J. 1970. Preliminary studies of an integrated control program for cucumber pests and
an evaluation of methods of introducing Phytoseiulus persimilis Athias-Henriot for the
control of Tetranychus urticae Koch. Ann. appl. Biol. 66: 503-513.

Gould, H. J. 1971. Large scale trial of an integrated control programme for cucumber pests on
commercial nurseries. P1. Path. 20: 149-156.

Scopes, N. E. A. and W. J. Parr. 1971. Big decision on predator control must be made. Grower

75 (13): 794-798.

A METHOD FOR REARING THE PREDACEOUS MITE,
PHYTOSEIULUS PERSIMILIS (ACARINA: PHYTOSEIIDAE)

T. L. THEAKER AND N. V. TONKS

Research Station, Agriculture Canada
Sidney, British Columbia

ABSTRACT

The predaceous mite, Phytoseiulus persimilis Athias-Henriot, was reared
successfully in a darkened growth chamber on blotting paper on a freezer
carton lid floated on water in a plastic saucer. Predators were fed with
twospotted spider mites collected from infested bean leaves with a mite

brushing machine.

INTRODUCTION

During studies initiated on the biological
control of the twospotted spider mite,
Tetranychus urticae Koch on_ greenhouse
cucumbers, we needed a simple method for
rearing the predaceous mite, Phytoseiulus
persimilis Athias-Henriot. Techniques -for
mass-rearing both host and predaceous mites
have been published (McMurtry and Scriven
1965, Scopes 1968, Scriven and McMurtry
1971, Anonymous 1975). This report describes
adaptations and innovations developed for our
own conditions and facilities.

METHODS AND DISCUSSION
We reared twospotted spider mites on bush
beans (Phaseolus vulgaris L. cv. Stringless
Greenpod) grown in 3:2:1 soil-peat-sand mix,

Contribution No. 237,
Canada, Sidney, B.C.

Research Station, Agriculture

'J. W. Gates, personal communication

planting 4 seeds in each 15 cm diameter plastic
pot. When the plants are about 30 cm high,
they are transferred to a growth chamber
maintained at 251°C with 16 hours of light.

Predaceous mites are reared in darkness
at 2541°C. Each culture is started by trans-
ferring 30 predaceous mites to a 9 cm disc of
blotting paper. This paper is placed on an inver-
ted 12 cm diameter lid from a freezer carton
(Plasti-Pak Containers, Toronto, Canada).
Wandering by the mites is minimized by
floating the lid on water in a plastic saucer
25 cm in diameter and 4.5 cm deep. The lid is
centred in the saucer by attaching one small
magnet to the bottom of the lid and a second
magnet in the bottom of the saucer. Another
25 cm plastic saucer is inverted over the culture
as a cover to maintain a high relative humidity
within the container.

Each predaceous mite culture is fed with
twospotted spider mites removed from infested
bean leaves with a mite brushing machine
(Henderson and McBurnie, 1943). We found

Se

J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), Dec. 31, 1977 9

that many mites were injured when leaves were
passed between both brushes of the machine,
so we removed one brush. The leaf can be
then pressed and moved gently against the
remaining brush with the hand until all the
mites are removed. Apparently the same effect
can be achieved on some machines by reversing
the belt drive so that the brushes rotate
outwards'. The mites are collected on a 12 cm
blotting paper disc and tapped off or brushed
from the paper onto the predator culture.
Cultures develop satisfactorily if fed three
times a week. Rate of increase varies among
cultures, but we have obtained 400 to 1000
predators from single cultures after 3 to 4
weeks. One culture will remain productive for

many weeks, but after about 6 weeks debris
accumulation interferes with collecting.
Collections are made with a small suction
aspirator. One person can collect at least 1000
mites an hour from vigorous cultures. Although
predators survive only a few hours when they
are collected in vials without any host mites,
they survive about 7 days in vials containing
mite-infested bean leaf sections.

Our relatively small demand for predaceous
mites required the services of one person for

_about 3 hours per week. This includes planting

about 20 pots of beans per week, maintaining
established plants and feeding 6 to 10 cultures.
The whole rearing procedure can be readily
expanded or reduced according to demand.

References

Anonymous. 1975. Biological pest control - rearing parasites and predators. Bull. No. 2, Glass-
house Crops Research Institute, Littlehampton, Sussex.

Henderson, C. F. and H. Y. McBurnie. 1943. Sampling techniques for determining populations of
citrus red mite and its predators. U.S. Dep. Agric. Circ. 671.

McMurtry, J. A. and G. T. Scriven. 1965. Insectary production of Phytoseiid mites. J. Econ.

Ent. 58: 282-284.

Scopes, N. E. A. 1968. Mass rearing of Phytoseiulus riegeli Dosse for use in commercial horticul-

_ture. Pl. Path. 17: 123-126.

Scriven, G. T. and J. A. McMurtry. 1971. Quantitive production and processing of Tetranychid
mites for large-scale testing or predator production. J. Econ. Ent. 64: 1255-1257.

THE FIRST RECORD OF CULISETA SIL VESTRIS MINNESOTAE
BARR IN BRITISH COLUMBIA (DIPTERA: CULICIDAE).

Curtis (1967) speculated that Culiseta
silvestris minnesotae likely occurred in British
Columbia since it has been taken near the
southern boundaries of the province. During
a routine light-trap survey in the municipality
of Port Coquitlam, a suburb of Vancouver,
British Columbia, two C.s. minnesotae females
were collected on July 12 and August 14, 1974.
The larvae of this species have not yet been
found in British Columbia.

Originally described by Barr (1957) as

Culiseta minnesotae, Stone (1967) assigned it
as a subspecies of Culiseta silvestris Shenga-
rev.
This finding brings the total number of
mosquito species recorded in British Columbia
to 41, and extends the known Canadian range
of this species from Ontario to the West Coast.
I wish to thank Dr. D. M. Wood of the
Biosystematics Research Institute, Agricul-
ture Canada, Ottawa, for confirming my
tentative determination of these specimens.

References
Barr, A. R. 1957. A new species of Culiseta (Diptera: Culicidae) from North America. Proc. Ent.

Soc. Wash. 59: 163-167.

Curtis, C. L. 1967. Mosquitoes of British Columbia. Occasional Papers, B.C. Provincial Museum,

No. 15, 90 pp.

Stone, A. 1967. A synoptic catalogue of the mosquitoes of the world, Supplement III (Diptera:
Culicidae). Proc. Ent. Soc. Wash. 69: 197-224.
R. A. Costello

British Columbia Ministry of Agriculture,
Cloverdale, B.C.

10

AND ITS MAJOR PARASITES IN THE CROWNS OF WESTERN

J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977

DISTRIBUTION OF COLEOPHORA LARICELLA
(LEPIDOPTERA: COLEOPHORIDAE)

LARCH IN BRITISH COLUMBIA?!
By GORDON E. MILLER? AND THELMA FINLAYSON?

ABSTRACT

The distribution of Coleophora laricella (Hbn.) and its parasites Dicla-
docerus spp. (D nearcticus Yosh. and D. pacificus Yosh. (Yoshimoto 1976))
and Spilochalcis albifrons (Walsh) in the crowns of western larch were
determined for five classes of trees. In open-grown trees more than 7.6 m
high, C. laricella densities were greater at 1.5-3.1 m than at 6.1-7.6 m above
the ground, on the sunny side of a tree than on the shaded side, and on the
outer half than on the inner half of a branch. In open-grown trees 3.0-4.6 m
high and in trees forming a closed canopy, only the outer branch halves had
significantly greater densities. The only significant variation in parasitism
by Dicladocerus spp. occurred between branch halves in open-grown, non-
roadside trees more than 7.6 m high, with more parasitism on the inner
halves than the outer. Parasitism by S. albifrons was significantly greater
at the lower crown level than at the higher in open-grown, closed-canopy,
non-roadside trees that were more than 7.6 m high, and on the outer branch
half than on the inner half in the same category of tree.

INTRODUCTION

Little is known about the within-tree
distribution of the larch casebearer, Coleophora
laricella (Hbn.) (Lepidoptera: Coleophoridae),
an introduced pest, and its major parasites in
British Columbia, in trees growing in different
situations, It is thus difficult to develop
adequate sampling procedures. Dicladocerus
spp. (D. nearcticus Yosh. and D. pacificus
Yosh. (Yoshimoto 1976) (Hymenoptera: Eulo-
phidae) andSpilochalcis albifrons (Walsh)
(Hymenoptera: Chalcididae) were by far the
most abundant species in a two-year survey of
parasites of C. laricella (Miller and Finlayson
1974, 1977).

METHODS
Crowns of 40 western larch trees in five
classes were sampled on 13 June 1974 at Shore-
acres, British Columbia. The five classes of
trees and the number in each class were:

Webb (1953) examined the distribution of
C. laricella on American larch, Larix laricina
(Du Roi) K. Koch, but only on large, open-
grown trees. There have been no published
reports of within-tree distribution of C. laricella
in western larch, Larix occidentalis Nutt.
Distributions of Dicladocerus spp. and S. albi-
frons on western larch have been reported by
Tunnock et al. (1972), but again only on large,
open-grown trees.

The objective of this study was to determine
the within-tree distributions of C. laricella,
Dicladocerus spp. and S. albifrons in western
larch trees growing in various situations, to
provide data that could improve sampling
techniques.

Class Description Number of trees

1 Open-grown trees at least 91.4 m 10
(100 yd.) from road and over 12.2 m
(40 ft.) high

Z Same as Class 1 except 7.6-10.7 m 10
(25-35 ft.) high

3 Same as Class 1 except 3.1-4.6 m 5
(10-15 ft.) high

4 Same as Class 1 except trees were 5
roadside

5 Same as Class 1 except trees formed 10

closed canopy. Trees sampled were at
least twice height of trees from the
edge of stand

‘Based on a thesis submitted by the senior author in partial
fulfillment of an M.Sc. degree

University, Burnaby, B.C. V5A 1S6

*Graduate student and Professor, respectively, Simon Fraser

J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977 i

Samples from Class 1 trees were also taken
on 15 May 1974 but were analyzed for distri-
bution of C. laricella only.

Samples were taken at two crown levels:
1.5-3.1 m (5-10 ft.) and 6.1-7.6 m (20-25 ft.)
above the ground. Two primary branches were
taken from both the sunny and shaded sides of
each tree from each crown level and cut in half.
The branch halves were mass-reared in pairs
according to tree, crown level, side of tree, and
branch half. Rearing was done in 30.5x61.0x
30.5 cm (1x2x1 ft.) cages constructed from
corrugated paper cartons, the tops of which
were replaced with 0.2 mm mesh.

Parasites were collected daily and placed
directly into 70% ethanol. After parasite
emergence was completed, host cases were
removed manually and the number of fascicles
counted.

For statistical analyses, log; x transfor-

mations were done on C. laricella densities
(number per 100 fascicles) and arcsine trans-
formations were calculated for percentage
parasitism data. In analyses of variance (Dixon
1973) of the intra-tree distributions of each
class, trees were allowed to go random, result-
ing in conservative F values. The data are
presented in the untransformed form.

RESULTS

There were no_ significant differences
between the tree classes in mean density of
C. laricella or mean percentage parasitism by
Dicladocerus spp. or by S. albifrons in the
crown levels (Table 1). C. laricella densities
varied significantly between crown levels,
between sides of the tree, and between branch
halves in Classes 1, 2 and 4; and between
branch halves only in Classes 3 and 5 (Figure

1). The densities were significantly higher
on the outer branch halves than on the inner
in all classes. Significantly higher densities
occurred at the lower crown level than at the
higher in Classes 1, 2 and 4 but no significant
differences occurred between crown levels in
Class 5. Densities were also significantly higher
on the sunny sides of trees than on the shaded
sides in Classes 1, 2 and 4 but no significant
differences between sides of trees occurred in
Classes 3 and 5. The distributions did not differ
in Class 1 trees between the two collections.

The only significant variation in parasitism
by Dicladocerus spp. occurred between branch
halves, with more parasitism on the inner than
on the outer halves, in Classes 1 and 2 (Fig. 2).

No significant variations occurred between
crown levels or sides of trees in any of the
classes, or between branch halves in Classes
3, 4 and 5.

Parasitism by S. albifrons was significantly
greater at the lower crown level than at the
higher in Classes 1, 2 and 5; and on the outer
branch halves than on the inner in Classes 1
and 2 (Fig. 3). No significant differences
occurred between branch halves in Classes 3,
4 and 5, or between crown levels in Class 4.

DISCUSSION

Webb (1953) found distributions of C. lari-
cella similar to those in the crown levels and
branch portion in open-grown tree classes 1
to 4 of this study, i.e., higher casebearer
densities at the bottom of the crown than at the
top and on the terminal part of the branch than
at the base. The abundance of C. laricella
larvae and pupae on the sunny side of the tree
and the outer half of the branch may reflect the
oviposition site preferences of the female moths

TABLE 1. Density of Coleophora laricella and percentage parasitism by Dicladocerus spp., and by
Spilochalcis albifrons in five classes of trees on 13 June 1974 at Shoreacres, British Columbia.

(X = mean, SD = standard deviation)

Crown C. laricella density

% Parasitism

Class Level (no./100 fascicles) Dicladocerus spp. S. albifrons
(ft.) x SD X SD x SD
1 5-10 Tort 5.7 6.5 2.6 oa 4.1
20-25 eel 2.6 8.4 2e9 4.2 3.1
2 5-10 174 4.5 ed 2.3 10.3 4.7
20-25 Sai eg OTs 2 5.8 3.8
3 5-10 13.2 2.8 ss 1.6 7 2.0
20-25 11.0 22 9.4 5.0 3.1 3.4
4 5-10 23.1 3.2 5.0 1.6 10 3.0
20-25 10.8 2.3 6.9 3.4 2.8 ye)
5 5-10 Piz 2.8 6.6 4.3 js 5.8

12 J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977

Shaded

50
Sunny /\ Shaded

May 15. 1974 collection June 13. 1974 collection

50 Sunny /{ Shaded Sunny Shaded

June 13, 1974 collection

Fig. 1. Schematic representation of within-tree distributions of Coleophora laricella in one class of
tree on 15 May 1974 and five classes of trees on 13 June 1974 at Shoreacres, British
Columbia. (Numbers represent number of casebearers per 100 fascicles, the outer being
those of the outer branch half and the inner those of the inner branch half)

J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEC. 31, 1977 1S}

30 Sunny / Shaded

40
= 30
k-
ae
O
LU
= OG
Sunny /A Shaded
10 wy K +
2
90 Sunny /\ Shaded
40
= 30
aa
Aa
O
TT
20
10

Fig. 2. Schematic representation of within-tree distributions of Dicladocerus spp. in five classes of
trees on 13 June 1974 at Shoreacres, British Columbia. (Numbers represent percentage
parasitism, the outer being those of the outer branch half and the inner those of inner

branch half)

14 J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977

90 Shaded
40
ce
ale
©
LU
aie
20
Shaded
10 120
87
50
40
ae
kK
ae
O
LU
0
10

Fig. 3. Schematic representation of within-tree distributions of Spilochalcis albifrons in five classes
of trees on 13 June 1974 at Shoreacres, British Columbia. (Numbers represent percentage
parasitism, the outer being those of the outer branch half and the inner those of the inner
branch half)

J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), Dec. 31, 1977 15

(Sloan and Coppel 1965; Webb 1953).

The distribution of Dicladocerus spp. could
be affected by movements of C. laricella after
parasitization. The amount of spring movement
by casebearer larvae is influenced by casebearer
density, greater movements occurring at higher
densities (Webb 1953). At the densities
observed in this study, casebearer movement
was not great enough to cause a difference in
the distribution of the host between the two
collections, the apparent period of parasitiza-
tion (Miller and Finlayson 1977) in Class 1
trees. Host movement probably is not a factor
in the distribution of S. albifrons as this species
apparently attacks the sessile pupae of the host
(Bousfield and Lood 1971).

The within-tree distributions of Diclado-
cerus spp. and S. albifrons in Classes 1 and 2
are similar to those in 9.1-12.2 m (30-40 ft.)
trees in the western United States (Tunnock
et al. 1972). The distributions of Dicladocerus
spp. and S. albifrons within trees probably
reduces competition for casebearers between
these species on open-grown trees (Tunnock
et al. 1972).

When measuring the degree of parasitism

of C. laricella, Bousfield and Lood (1971) took
their samples from the terminal 45.7 cm (18’’)
of branches rather than whole branches. In
open-grown trees more than 7.6 m (25 ft.) high,
such a sampling technique would overestimate
parasitism by S. albifrons and underestimate
parasitism by Dicladocerus spp.

The differences in distributions of both
C. laricella and its parasites between classes
must be considered when measuring casebearer
populations or parasitism, especially if less
than whole-branch samples are taken, and when
sampling trees of differing types.

ACKNOWLEDGMENTS

We thank Drs. A. L. Turnbull and J. A.
McLean, Department of Biological Sciences,
Simon Fraser University, for advice on the
statistical analyses. We are grateful for
financial support for this work from National
Research Council Grant No. A4657 and in 1973
from Contract OSP3-0228 from the Pacific
Forest Research Centre, Canadian Forestry
Service, Department of the Environment,
Victoria, B.C.

References
Bousfield, W. E. and R. C. Lood. 1971. Impact of parasites on the larch casebearer in the Northern
Region 1970. U.S.D.A. For. Serv. Rept. 71-4, Northern Region, Missoula, Mont.
Dixon, W. J. 1973. BMD Biomedical Computer Programs. Univ. of Calif. Press, Los Angeles.
Miller, G. E. and T. Finlayson. 1974. Native parasites of the larch casebearer, Coleophora laricella
(Lepidoptera: Coleophoridae), in the west Kootenay area of British Columbia. J. entomol.

Soc. Brit. Colomb. 71: 14-21.

Miller, G. E. and T. Finlayson. 1977. Parasites of the larch casebearer, Coleophora laricella (Lepi-
doptera: Coleophoridae), in the West Kootenay area, British Columbia. J. entomol. Soc.

Brit. Columb. (in press).

Sloan, N. F. and H. C. Coppel. 1965. Oviposition patterns and egg predation of the larch case-
bearer, Coleophora laricella Hbn. in Wisconsin. Univ. of Wisconsin For. Res. Note. No.

124.

Tunnock, S., M. McGregor and W. E. Bousfield. 1972. Distribution of larch casebearer parasites
in the crowns of western larch trees in the Northern Region. U.S.D.A. For. Serv. Rept.
72-4, Northern Region, Missoula, Mont.

Webb, F. E. 1953. An ecological study of the larch casebearer, Coleophora laricella Hbn. (Lepidop-
tera: Coleophoridae). Ph.D. Thesis, Univ. of Michigan, Ann Arbor, Mich.

Yoshimoto, C. M. 1976. Revision of the genus Dicladocerus (Eulophidae: Chalcidoidea) of America

north of Mexico, with particular reference to species attacking larch casebearer (Lepidop-
tera: Coleophoridae). Can. Ent. 108: 1173-1206.

16 J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977

PARASITES OF THE LARCH CASEBEARER,
COLEOPHORA LARICELLA (LEPIDOPTERA: COLEOPHORIDAE).
IN THE WEST KOOTENAY AREA, BRITISH COLUMBIA?

GORDON E. MILLER? AND THELMA FINLAYSON:?

ABSTRACT

The parasite complex of the larch casebearer, Coleophora laricella (Hbn.),
was investigated in the Kootenay area of British Columbia in 1973 and 1974.
Forty-one species of hymenopterous parasites were obtained from rearings
of almost 153,000 final-instar host larvae and pupae. In 1973 and 1974, 31
and 24 species, respectively, were reared, with 14 common to both years.
Twenty-nine of these, in 24 genera, were confirmed as larch casebearer
parasites by individual rearings and by reports in the literature. No
parasites were obtained from eggs, needle-mining larvae, or third-instar

case-bearing larvae. The highest total percentage parasitism was 17.7%

in 1973 and 24.5% in 1974, both at Rossland. In Collection II the
Dicladocerus spp. complex comprised 46.0% of the total parasitism in 1973,
and 63.8% of the total in 1974; it was the most abundant at four of the
eight collecting sites in 1973 and 13 of the 14 sites in 1974. Spilochalcis
albifrons (Walsh) comprised 32.8% and 23.5% of the total parasitism in the
years 1973 and 1974 respectively; it was most abundant at three collection
sites in 1973 and at two in 1974. Mesopolobus sp. constituted 4.9% of the
total in 1973 and 9.9% in 1974. Larch casebearer densities in the first
collection in 1973 were highest at Fruitvale and Shoreacres with 150 and
130 cases per 100 fascicles respectively; in 1974, the highest host densities
in the first collection were at Kootenay Bay and Fruitvale with 48 and 41

cases per 100 fascicles respectively.

INTRODUCTION
The larch casebearer, Coleophora laricella
(Hbn.) (Lepidoptera: Coleophoridae), a

European species introduced into western
North America, is currently a target of
biological control efforts. Releases of exotic
parasites have been in progress for about 17
years (Denton 1972; Morris and Monts 1972;
Ryan and Denton 1973; Ryan et al. 1975, 1977).

Turnbull and Chant (1961) argued ‘that the
ecology of a pest being considered for a
biological control programme should be studied
in the area of proposed release prior to the
introduction of natural enemies. To determine
the identities of parasites and degree of parasi-
tism of C. laricella in British Columbia, surveys
were carried out in 1973 and 1974. Results of
the 1973 survey were reported by Miller and
Finlayson (1974).

METHODS
Procedures in 1974 were similar to those
used in the 1973 survey and were described by
Miller and Finlayson. Samples were taken in
1973 at eight sites: Anarchist Summit, Arrow
Creek, Cascade (=Christina Lake), Fruitvale,
Rossland, Sheep’s Creek, Shoreacres, and

'Based on a thesis submitted by the senior author in partial
fulfillment of an M.Sc. degree.

*Graduate student and Professor, respectively, Simon Fraser
University, Burnaby, B.C. V5A 1S6

Yahk. In 1974 these eight were again investi-
gated plus the following additional six sites:
Cranbrook, Johnstone Creek Park, Kootenay
Bay, Roosville, Rykerts and Winlaw (Fig. 1).
Collection I on May 14-15, 1974, consisted
mainly of final-instar larvae and Collection II
on June 12-13, mainly of pupae.

Ten trees were sampled in each collection at
1.5 - 3.0 m (5-10 ft.) and at 6.1 - 7.6 m (20-25 ft.)
Five primary branches were taken from the full
circumference of each tree at each height.
Mass-rearing was done in 30.5x61.0x30.5 cm
(1x2x1 ft.) cardboard boxes in which the tops
had been replaced by 0.2 mm mesh. Individual
rearing of larvae and pupae collected at
Cascade, Rossland, Sheep’s Creek and Shore-
acres in 1974 was done in % dram vials to
which fresh larch needles were supplied as
required by the feeding larvae.

Eggs were collected both years from 10
trees at each site and mass-reared in petri
dishes. Early larval instars were collected at
Rossland and Shoreacres in August and
October, 1973. These were mass-reared in
approximately the same way as the later
instars.

RESULTS
A total of 134,511 C. laricella were mass-
reared: 102,947 in 1973 and 31,564 in 1974;
and 18,300 were reared individually in 1974.
In 1974 there were 20,168 casebearers in
Collection I and 11,396 in Collection II, whereas

J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977

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ANY Gv
A NR NS ~~
\NN AAS 10% ~ 12S UNS |
ee ENA ASA 6 RS
COLEECTION SIMES
1 ANARCHIST SUMMIT 8 WINLAW
2 JOHNSTONE CREEK PARK 9 KOOTENAY BAY
3. CASCADE 10 ARROW CREEK
4 ROSSLAND 11 RYKERTS
5 FRUITVALE WZ YAHK
6 SHEEP'S CREEK 13. CRANBROOK
7 SHOREACRES 14 ROOSVILLE

Fig. 1. Distribution of Coleophora laricella in British Columbia in 1972 and location of the collection
sites in 1973 and 1974. (Adapted from R. F. Shepherd and D. A. Ross, ‘‘Problem analysis: larch
casebearer in B.C.’’ Unpublished Internal Report BC-37, Pac. For. Res. Cent., Victoria, B.C. 1973).

17

18 J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), Dec. 31, 1977

the comparable collections in 1973 amounted to
40,695 and 62,242. As more samples were taken
in 1974 than in 1973, the figures indicate a con-
siderable reduction in populations over the
range of this species in British Columbia
between the two years.

In 1974, a total of 1,989 specimens of 24
species of hymenopterous parasites and hyper-
parasites were reared as compared with 4,459
specimens of 31 species in 1973 (Miller and
Finlayson 1974). The total number of species
obtained in the two years was 41, with 14
common to both.

Table 1. Confirmed parasites from mass-rearings of Coleophora laricella in British,
Columbia in 1973 and 1974

1973
May 8-9
No. No.
Hymenopterous Parasites

Abundance
1974
May 23-25 May 14-15 June 12-13
No. No. No. No. No. No.

Obtained Sites? Obtained Sites? Obtained Sitesb Obtained Sites?

Braconidae
Bracon pygmaeus Prov.',’,®
Ichneumonidae
Campoplex rufipes Prov.’
Diadegma sp.',?
Gelis tenellus (Say)', ’,
Gelis sp. ', ’, °
Itoplectis vesca Townes !
Pristomerus sp. ', ”
Scambus decorus Walley !

Eulophidae
Achrysocharella sp. ', ?
Chrysocharis laricinellae
( Ratz.) 7;°
Cirrospilus pictus (Nees)
Dicladocerus spp. (2) ', ”, °
Elachertus proteoteratis
(How.) *
Euderus cushmani (Crawford) 3
Eulophus sp. ** 2 i
Tetrastichus dolosus (Gahan) ?
Tetrastichus ecus Wlkr. ', ”
Zagrammosoma americanum
Gir. ?

Encyrtidae
Copidosoma sp.’

Pteromalidae
Catolaccus aeneoviridis (Gir.) ?,
Habrocytus phycidis Ashm. ”, * Ll
Mesopolobus sp. ', ” 15 2

Chalcididae
Spilochalcis albifrons (Walsh) ', ?, *

32 5

325 8

—_

Eurytomidae
Eurytoma sp. 3*

Diapriidae
Telenomus spp. (3) **
Trissolcus sp. **

273 8 9 5 6 4
2 i
3 2 1 1
2 2 2 2
) 4 3 2
1 1 2, i
2 1 4 4 4 3
10 2 4 2 2 1
30 3 7 2 3 1
5 2 1 1
1 1
1,480 8 693 14 669 14
1 1
2 1
2 1
2) 2
142 5 1 1
10 1 2 it
1 1
2 1
5 2
158 6 ail 9 104 wy)
1,054 6 247 7
1 1
6 2
10 2

a-out of 8 b-out of 14

1 confirmed by individual rearings in this study
2 confirmed by Bousfield and Lood (1973)

3 confirmed by Webb (1953)

* confirmed to genus only.

J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), Dec. 31, 1977

19

Table 2. Relative abundance of the confirmed Coleophora laricella parasite species obtained from
mass-rearings of C. laricella in British Columbia in 1973 and 1974 (in per cent)

1973 1974
Species May 8-9 May 23-25 May 14-15 June 12-13
Dicladocerus spp. 86.7 46.0 83.2 63.8
Spilochalcis albifrons 52:5 20.0
Bracon pygmaeus 8.5 8.5 0.6
Mesopolobus sp. 4.9 13.3 9.9
Tetrastichus ecus ° 4.4 0.1
Other (no. of species) 4.8 (3) 30 (19) B00) 2 N12)

Some of the parasites that emerged from
mass-reared samples could have come from
hosts other than C. laricella that were
accidentally included in the collections. A mass-
reared parasite was considered to have come
from C. laricella only if it had been obtained
from the individual rearings in this work, or
had been verified previously (Bousfield and
Lood 1973; Denton 1972; Sloan 1965; Webb
1953).

Twenty-nine species have been confirmed as
parasites of C. laricella (Table 1). The 12
species not considered to be casebearer para-
sites are: Aphidius sp. (Aphidiidae); Acrolyta
sp., Hyposoter sp. (Ichneumonidae);
Aprostocetus spp. (2), Diglyphus _ sp.,
Melittobia sp. (Eulophidae); Thysanus sp.
(Thysanidae); Cyrtogaster vulgaris Whlkr.
(Pteromalidae); Aphanogmus sp. (Ceraphroni-
dae); and Aclista sp. (Diapriidae).

Most of the confirmed species represent new
host records for British Columbia. Gelis
tenellus (Say), Scambus decorus Wly., Tetrasti-
chus ecus Wlkr. [=xanthops(Ratz.) | and Spi-

lochalcis albifrons (Walsh) were previously
recorded by Andrews and Geistlinger (1969).
These workers also obtained Bracon sp. which
may well have been B. pygmaeus Prov;
Amblymerus sp. which probably is the same as
the Mesopolobus sp. found in this study; and a
species reported as Dicladocerus westwoodii
Westw. which may be either of the two new
species found in this study, D. nearcticus
Yosh. or D. pacificus Yosh. (Yoshimoto 1976).
Two species not taken in the study but which
have been reported previously as parasites of
C. laricella in British Columbia are Scambus
transgressus (Holmg.) and _ Sceptrothelys
deione (Wlkr.) (Andrews and Geistlinger 1969).

Although many parasite species were ob-
tained, only a few predominated, with
Dicladocerus spp. and S. albifrons being by far
the most abundant (Table 2). The most abun-
dant species were also the most widespread
(Table 1). Dicladocerus spp. and Mesopolobus
sp. increased in relative abundance in 1974
when compared with 1973, while the other
species that were relatively abundant in 1973

Table 3. Summary of confirmed parasites from mass-rearings of Coleophora laricella collected at
14 locations in British Columbia on May 14-15, 1974 .

Parasitism
C.laricella |Dicladocerus spp. Mesopolobus sp. Other Total
No. of Cases/100 No. of No. No. No. No. of

Location Cases Fascicles|Emerged “ | Emerged Reared % Reared Taxa h
Anarchist Summit 95 1.2 1 jal 1 ioe
Arrow Creek 2,126 29.8 36 17. 9 0.4 3 0.1 48 2aced
Cascade 1,488 17.7 61 4.1 g 0.6 8 (0.5 78 7 Fo-2
Cranbrook 53 0.6 3 Del 33 1 ek
Fruitvale 2,774 40.8 86 oul 11 0.4 11 0.4 108 Sitord
Johnstone Creek Park 169 8.5 2 12 2 LZ
Kootenay Bay A275 47.8 9 O02 4 0.1 S01 @ 1s 2 0.4
Roosville 61 0.7 3 4.9 3 1 4.9
Rossland 832 8.0 54 6.5 3 04 9 11 66 4 7.9
Rykerts 4,619 21.9 162 3.5 HAGE 0.6 3 O.1 192 2 4.2
Sheep’s Creek 1,873 19.7 121 6.5 31 eye. 19! «710: ala 5 9.1
Shoreacres 1,604 25.4 150 9.4 18 L243. 70:8) Sl 6 11.3
Winlaw 94 G2 4 4.3 1 en 5 2 5.3
Yahk 105 0.8 1 0 1 1.0 2 1 1.9

J. ENTOMOL, Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977

20

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J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), Dec. 31, 1977 21

decreased, relatively. In 1974, Dicladocerus
spp. were the most abundant at all locations in
the first collection (Table 3) and at 13 in the
second (Table 4). In 1973, Dicladocerus spp.
were the most abundant at six of the eight
locations in the first collection and at five in the
second collection; B. pygmaeus was the most
abundant at two in the first collection and one
in the second; and S. albifrons was the most
abundant at two in the second (Miller and
Finlayson 1974).

Greater parasitism, in terms of both number
of taxa and percentage parasitism, occurred
in the second collection than in the first in both
1973 (Miller and Finlayson) and 1974 (Tables 1,
oe 4).

The greatest casebearer densities per 100
fascicles in 1974 were at Kootenay Bay and
Fruitvale where there were, respectively, 47.8
and 40.8 in the first collection and 36.0 and 26.1
in the second (Tables 3, 4). The greatest total
percentage parasitism of 24.5% occurred at
Rossland where host density was 3.9 case-
bearers per 100 fascicles. Percentages of para-
sitism at the various locations were not related
to host densities, as was also the case in 1973
(Miller and Finlayson 1974).

Achrysocharella sp. was the only gregarious
parasite species indicated by individual
rearings. The mean number of adults produced
from four cases was 3.25. Bousfield and Lood
(1971) also found a very low incidence of
gregariousness. However, they found three
species, Achrysocharella silvia Gir., T. ecus
and Mesopolobus sp., that occasionally pro-
duced more than one adult per case.

No parasites emerged from mass-rearings
of 2,427 eggs, 19,279 needlemining larvae, or
6,890 fall-collected, casebearing, third-instar
larvae.

DISCUSSION

The parasite complex and incidence of para-
sitism on C. laricella in British Columbia were
comparable to those in other areas of North
America (Bousfield and Lood 1971, 1973;
Denton 1972; Sloan 1965; Webb 1953). The
parasite complex also resembles the complexes
in the Alps region of Europe (Jasch 1973),
although more major species, in terms of rela-
tive abundance and constancy, occurred in the
Alps. There was a low incidence of three species
of parasites in needle-mining larvae and case-
bearing, third-instar larvae in the Alps,
whereas no parasites were taken from these
stages in British Columbia. There are no
reports of parasites that emerge from C. lari-
cella eggs.

Miller and Finlayson (1974) reported two
European species that had been released
against C. laricella in eastern North America
in the 1930’s: Chrysocharis laricinellae (Ratz.)
and Cirrospilus pictus (Nees). C. laricinellae

was found again in 1974. Ryan et al. (1974)
give possible explanations for the presence
of these species.

Agathis pumila (Ratz.) (Braconidae) is
conspicuous by its absence in this survey. It
was released against C. laricella in British
Columbia in 1969 and has since become estab-
lished (Morris and Monts 1972). One of the
release sites was less than one mile from the
Arrow Creek location in this study.

The increase in parasitism between the two
collections in both 1973 and 1974 indicates that
adult parasites are active during this period
and/or that C. laricella reaches a more suscep-
tible stage. Sweep-net collections of adults of
B. pygmaeus, I. vesca, Dicladocerus spp. and
Mesopolobus sp. during the first 1974 collection
confirmed their presence in the field during this
period. The increase in parasitism by S. albi-
frons between collections was probably correla-
ted with the increase in host pupal populations
between collections, as pupae are thought to be
the stage attacked by this species (Bousfield
and Lood 1971). Similar increases in parasitism
of C. laricella and other coleophorids during the
spring-feeding period have been _ reported
(Beacher 1947; Bousfield and Lood 1971;
Doner 1934).

Mortality of C. laricella caused by the native
parasites may be limited by the number of
alternate hosts available to the parasites in the
absence of suitable instars of C. laricella as
these, or related species, are known to have
more than one generation per year (Clausen
1962; Dowden 1941; Jasch 1973) and not all of
them can be spent on C. laricella. S. albifrons is
more dependent on alternate hosts than other
species as very few females (2.5% of the species
total in 1973 and 0.0% in 1974) emerged from
C. laricella in this study.

A positive trend was noted between total
percentage parasitism and the total number of
lepidopteran and sawfly larvae (which may or
may not be alternate hosts of the parasites
taken) at five of the sites. In eastern Canada
the introduced species C. laricinellae, is much
more effective against C. laricella in the
presence of A. pumila or in the presence of
alternate hosts due to improved synchroni-
zation (Quednau 1970). The lack of alternate
hosts has been suggested as a limiting factor of
parasitism in other coleophorids (Beacher
1947; Doner 1934, 1936).

Species of exotic parasites that have been
recently released, or that are contemplated for
release, against C. laricella in western North
America are taxonomically related to the native
species reared in this study. They also are non-
specific and non-synchronized with C. laricella
(with the exception of A. pumila) and have a
minor role in reducing larch casebearer popula-
tions in Europe (Jasch 1973). For these

22 J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977

reasons, the probability that they will be effec- Agriculture, Ottawa, Ont., for identifying the
tive biological control agents in western North parasites. The work was supported by National
America is questionable. Research Council Grant No. A4657 and in
ACKNOWLEDGMENTS 1973 by Contract OSP3-0228 from the Pacific
We thank Drs. J. R. Barron, L. Masner, Forest Research Centre, Canadian Forestry
W. R. M. Mason, C. M. Yoshimoto, and Messrs. Service, Department of the Environment,
H. E. Bisdee and M. Ivanochko, Entomology Victoria, B.C., for both of which we express our
Research Institute, Canada Department of appreciation.

References
Andrews, R. J. and N. J. Geistlinger. 1969. Parasites of the larch casebearer, Coleophora laricella
(Hbn.), in British Columbia (Lepidoptera: Coleophoridae). J. entomol. Soc. Brit. Columb.
66: 50-51.

Beacher, J. H. 1947. Studies of pistol case-bearer parasites. Ann. ent. Soc. Am. 40: 530-544.

Bousfield, W. E. and R. C. Lood. 1971. Impact of parasites on the larch casebearer in the Northern
Region 1970. U.S.D.A. For. Serv. Rept. 71-4, Northern Region, Missoula, Mont.

Bousfield, W. E. and R. C. Lood. 1973. Parasites of the larch casebearer in Montana, Idaho, and
Washington. Environ. Ent. 2: 212-213.

Clausen, C. P. 1962. Entomophagous Insects. Hafner Publ. Co., New York.

Denton, R. E. 1972. Establishment of Agathis pumila (Ratz.) for control of larch casebearer, and
notes on native parasitism and predation in Idaho. U.S.D.A. For. Serv. Res. Note
INT-164, Intermt. For. and Range Exp. Stn.

Doner, M. H. 1934. Observations on the biology of Microbracon pygmaeus (Prov.), an important
parasite of Coleophora pruniella Cl. Ann. ent. Soc. Am. 27: 435-442.

Doner, M. H. 1936. Hymenopterous parasites of Coleophora pruniella CL., and parasites recorded
from other species of Coleophora. Ann. ent. Soc. Am. 29: 224-244.

Dowden, P. B. 1941. Parasites of the birch leaf-mining sawfly (Phyllotoma nemorata). U.S.D.A.
Tech. Bull. 757.

Jasch, A. 1973. Populationsdynamik und Parasitenkomplex der Larchenminiermotte, Coleophora
laricella Hbn., im natiirlichen Verbreitungsgebiet der Europdischen Larche, Larix decidua
Mill. Z. angew. Ent. 73: 1-42.

Miller, G. E. and T. Finlayson. 1974. Native parasites of the larch casebearer, Coleophora laricella
(Lepidoptera: Coleophoridae), in the west Kootenay area of British Columbia. J. entomol.
Soc. Brit. Columb. 71: 14-21.

Morris, E. and J. Monts. 1972. Larch casebearer infestations in Nelson Forest District, 1972. Can.
For. Serv., Forest Insect & Disease Surv. Pest Rept., Pacific Forest Research Centre,
Victoria, B.C.

Quednau, F. W. 1970. Competition and cooperation between C. laricinellae and A. pumila on larch
casebearer in Quebec. Can. Ent. 102: 602-612.

Ryan, R. B., W. E. Bousfield, R. E. Denton, R. L. Johnsey, L. F. Pettinger and R. F. Schmitz.
1975. Additional releases of larch casebearer parasites for biological control in the
western United States. U.S.D.A. For. Serv. Res. Note PNW-242.

Ryan, R. B., W. E. Bousfield, C. W. Johanningmeier, G. B. Parsons, R. F. Schmitz and L. J.
Theroux. 1977. Releases of recently imported larch casebearer parasites for biological
control in the western United States, including relocations of Agathis pumila. U.S.D.A.
For. Serv. Res. Note PNW-290.

Ryan, R. B., W. E. Bousfield, G. E. Miller and T. Finlayson. 1974. Presence of Chrysocharis lari-
cinellae, a parasite of the larch casebearer, in the Pacific Northwest. J. econ. Ent. 67: 805.

Ryan, R. B. and R. E. Denton. 1973. Initial releases of Chrysocharis laricinellae and Dicladocerus
westwoodii for biological control of the larch casebearer in the western United States.
U.S.D.A. For Serv. Res. Note PNW-200.

Sloan, N. F. 1965. Biotic factors affecting populations of the larch casebearer Coleophora laricella
Hbn. in Wisconsin. Ph.D. Thesis, Univ. of Wisconsin, Madison, Wisc.

Turnbull, A. L. and D. A. Chant. 1961. The practice and theory of biological control of insects in
Canada. Can. J. Zool. 39: 697-753.

Webb, F. E. 1953. An ecological study of the larch casebearer, Coleophora laricella Hbn. (Lepidop-
tera: Coleophoridae). Ph.D. Thesis, Univ. of Michigan, Ann Arbor, Mich.

Yoshimoto, C. M. 1976. Revision of the genus Dicladocerus (Eulophidae: Chalcidoidea) of America
north of Mexico, with particular reference to species attacking larch casebearer (Lepidop-
tera: Coleophoridae). Can. Ent. 108: 1173-1206.

_ J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977 23

FEEDING POTENTIAL OF PREDATORS OF
MYZUS PERSICAE'/

GEORGE TAMAKI AND DARRYLL OLSEN

Yakima Agricultural Research Laboratory,
Agric. Res. Serv., USDA, Yakima, WA 98902

ABSTRACT

A rate of feeding for predator insects on th green peach aphid, Myzus
persicae (Sulzer), was determined based on the number of aphids consumed
from a more natural environment corrected for reproduction and natural
death. Of the predator species studied, the largest, Coccinella transverso-
guttata Falderman, consumed about 10 times more aphids than the
smallest, Orius tristicolor (White), and about 7 times more than the average

for all other predator species combined.

INTRODUCTION

Pest management specialists working in
the Yakima Valley of central Washington have
needed a method of relating the abundance of
certain predator insects to their potential effect
on populations of the green peach aphid (GPA),
Myzus persicae (Sulzer). A predictive model
was therefore developed whereby the numerical
census of a predator species is converted to
factors that reflect the reductive impact of the
predator complex against the GPA (Tamaki
et al. 1974). Thus, one component of this model
separates the predator complex into discrete
groups, each with gross similarities in feeding
capacity. Then each group is assigned a
numerical factor related to its rate of consump-
tion of aphids. The feasibility of the model was
demonstrated by using factors drawn from date
provided by Goodarzy and Davis (1958) and
Simpson and Burkhardt (1960), concerning the
predators of the spotted alfalfa aphid, Therioa-
phis maculata (Buckton), for demonstrating
the feasibility of the model, but we now needed
factors applicable to the predators of the
GPA found in the Yakima Valley. However,
workers studying aphidophagous predators in
the past have usually introduced known
number of prey into cage with a predator and
then counted the number dead, partially eaten,
or missing. Such a procedure cannot provide
an accurate estimate of the impact of predators
on a viable population of aphids. We therefore
altered the procedure by providing a host plant
for the aphids when we exposed them to preda-
tors so as to incorporate the effects of repro-
duction of the aphids and natural mortality
on the prey searching of the predators. We-also
examined the apparent role and abundance of
predator species in the field.

MATERIALS AND METHODS
In 1973, single adult predators were placed
on a bouquet of sugarbeet leaves in 1-pint ice
cream carton cages located at random on a
laboratory bench under daylight-fluorescent

'/ Hemiptera: Aphididae.

lighting, which provided a 16 h photophase.
Then 100 GPA from the laboratory colony
(3rd and 4th instars and adults) were placed
in each cage. The cages were examined each
morning for 3 days (days 2, 3, and 4) after the
predators were introduced and the number of
aphids was counted. Also, on days 2 and 3,
sufficient aphids were added to bring the total
in each cage to 100. The smaller species of
predators were found to consume only ca. 10 of
the aphids/day; the larger species consumed
ca. 50. The resulting differences between cages
in the age distribution and reproduction of
the aphids then produced inconsistent numbers
of prey consumed. Therefore, in 1974, we used
sugarbeet leaf bouquets and ice cream carton
cages as before but reduced the number of
aphids available to the smaller predators to
20/day. In this way all species of predators
actually consumed about 50% of the prey
available. Also, in 1973 and 1974, we noted that
reproduction and natural mortality of the
aphids began to be affected by the deteriora-
tion of the bouquets by the 4th day of the test.
Therefore, in 1975, the aphids were placed on
small sugarbeet plants in large plastic cages
(Fig. 1). Otherwise (numbers of aphids per cage
per day), the procedure was like that in 1974.

The insect predators used in the test were
collected in the field from sugarbeet, clover, or
alfalfa. Three species (determined by availabili-
ty) were tested each week through the growing
season.

Temperatures during the test period avera-
ged 24°C (range of 19-33°C); the RH averaged
46% (range 44-48%). Rate of predation was
determined as the average of the difference
between the number of aphids available at the
beginning of each day minus the number
remaining after each day for 4 days. Each
treatment was replicated 10 times on each of
the 4 days.

RESULTS AND DISCUSSION
Although the difference in the test proce-
dures in 1974 and 1975 resulted in differences

24

spryde pue 10}epeid a4e[OSI 07 posn aed *T “SIq

1

J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977

in aphid reproduction and natural death, the
feeding rate for a given species of predator
was similar both years; therefore, these data
were combined in Table 1. Also, the data for the
2 Bembidion spp. were combined because only
small numbers were tested and the feeding
rates were very similar. Plainly, the size of the
predator was of major importance. Thus, the
daily consumption of GPA by Coccinella
transversoguttata, the largest of the predators
studied, was 10 times that of the smallest
predator, Orius tristicolor, 5 times that of the
combined average of all the other predator
species listed in Table 1.

25

In the field, C. transversoguttata, one of the
large coccinellid species, was more common
than Hippodamia convergens Guérin-Meéneville.
Nabis alternatus was more common sugar-
beets, alfalfa, and clover than N. americoferus
Carayon though the latter was found frequent-
ly in these crops. Geocoris bullatus, which is
larger than G. pallens, consumed ca. 2 more
aphids/day. However, G. pallens was the most
abundant in sugarbeets and potatoes; G.
bullatus generally inhabits more permanent
grass covers such as floors of orchards and
also many perennial forage crops (Tamaki
1972). Little is known of Scymnus margini-

Table 1. Average rate of predation of green peach aphid by selected adult predators.

Mean (+ se)

No. of

Species predators predation/day per predator
Coccinella

transveroguttata Falderman 70 52.10+ 3.438
Nabis

alternatus Parshley 100 10.37 = .62
Anthocoris

melanocerus Reuter 50 8.46 + .74
Geocoris

bullatus (Say) 80 8:30 = 57
Scymnus

marginicollis Mann 90 7.99 + .43
Bembidion

spp. 40 6.66 + .67
Geocoris

pallens Stal 80 6.47 + .52
Orius

tristicolor (White) 90 hole A3

collis except that we have frequently observed
the larvae and adults of this small coccinellid
feeding on GPA on sugarbeets.

The two small carabids, Bembidion
obscurellum Mots. and B. rupicola Kby., were
ajbundant in some fields of sugarbeets and
potatoes. In the laboratory, these species will
feed on larval scab gnat, Pnyxia_ scabiei
(Hopkins), and GPA. Mitchell (1963) reported
that the crop contents of Bembidion lampros
(Herbst) consisted of parts of collembolans,
small mites, and earthworm material and that
in the laboratory, the adults and larvae would
feed on most types of invertebrate animal prey
found in soil samples.

Anthocoris melanocerus Reuter and Orius
tristicolor are in the same family, Anthocoridae,
but A. melanocerus is ca. 4-5 times larger than
O. tristicolor and consumed nearly twice as
many GPA. A. melanocerus is primarily known

as a predator of psyllids on deciduous fruit
trees (Madsen 1961 and Watson and Wilde
1963); however, it has also been reported
feeding on aphids on many vegetable and
forage crops (Tamaki and Weeks 1968). Orius
tristicolor was rarely observed to feed on
aphids in the field; in fact, it was seen to run
between aphids in attempts to capture a thrip.
Smith and Hagen (1956) also reported that O.
tristicolor preferentially fed upon mites and
thrips, rarely aphids. In the _ laboratory,
however, O. tristicolor will feed on aphids if no
other prey is available.

Although the feeding rates of the predators
that we report are based on laboratory studies,
most of these predators (except O. tristicolor
and Bembidion spp.) would probably feed at
the same rates in the field if aphids were
abundant. However, when aphid numbers are
minimum, searching time and prey preference
would probably lower the rates.

26 J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), Dec. 31, 1977

Geocoris pallens

insect predators

Myzus persicae - green peach aphid
Nabis alternatus

Orius tristicolor

Scymnus marginicollis

Predators of Myzus persicae
Anthocoris melanocerus
Bembidion spp.

biological control

Coccinella transversoguttata
Geocoris bullatus

References
Goodarzy, K., and D. W. Davis. 1958. Natural enemies of the spotted alfalfa aphid in Utah. J.:
Econ. Entomol. 51: 612-6.

Madsen, H. F. 1961. Notes on Anthocorus melanocerus Reuter (Hemiptera: Anthocoridae) as a
predator of the pear psylla in British Columbia. Can. Entomol. 93: 660-2.

Mitchell, B. 1963. Ecology of the two carabic beetles, Bembedion lampros (Herbst) and Trechus
quadristriatus (Shrank). I. Life cycles and feeding behavior. J. Anim. Ecol. 32: 289-99.

Simpson, R. G., and C. C. Burkhardt. 1960. Biology and evaluation of certain predators of Therio-
aphis maculata (Buckton). J. Econ. Entomol. 53: 89-94.

Smith, R. F., and K. S. Hagen. 1956. Enemies of spotted alfalfa aphid. Calif. Agric. 10: 8-10.

Tamaki, G. 1972. The biology of Geocoris buttalus inhabiting orchard floors and its impact on
Myzus persicae on peaches. Environ. Entomol. 1: 559-65.

Tamaki, G., J. U. McGuire, and J. E. Turner. 1974. Predator power and efficacy: A model to
evaluate their impact. Environ. Entomol. 3: 625-30.

Tamaki, G., and R. E. Weeks. 1968. Anthocoris melanocerus as a predator of the green peach aphid
on sugarbeets and broccoli. Ann. Entomol. Soc. Am. 61: 579-84.

Watson, T. K., and W. H. A. Wilde. 1963. Laboratory and field observations of two predators of
pear psylla in British Columbia. Can. Entomol. 95:435-8.

THE SYSTEMATIC POSITION OF THE
APPLE-AND-THORN SKELETONIZER:

This moth, also known as squeletteuse du
pomier et du cenellier (Benoit 1975), has been
referred to in North America as Anthophila
pariana (Cl.) since the 1930’s and usually as
Hemerophila pariana (Cl.) before then. To
check its identity in Western Canada the
genitalia and the external morphology of
specimens from the Vancouver, B.C., area were
compared with data in European studies on the
taxonomy and systematics. It was confirmed
that the species found in the Vancouver
district, where it was usually abundant in

1976, is a single species rather than a complex
and is the same species found in Europe and
the USSR; but that, in line with the con-
clusions of Danilevsky (1963) and Danilevsky
and Kuznetzov (1973), it is of the genus
Hemerophila Hubn. rather than of Anthophila
Haw. The correct name of the species found in

the Vancouver district, and presumably
elsewhere in North America, is_ therefore
Hemerophila pariana (Cl.). - M. Doganlar,

Pestology Centre, Simon Fraser University,

Burnaby, B.C.

References
Benoit, P. 1974. Noms Francais d’Insectes au Canada. Agric. Que. publ. QA38-R4-30.
Danilevsky, A. S. 1963. [new species of Glyphipterygidae (Lepidoptera) in the USSR] Ent. Rev.

48: 585-593.

Danilevsky, A. S., and V. I. Kuznetzov. 1973. [A review of the Glyphipterygid moths of the genus
Hemerophila Hb. (Lepidoptera, Glyphipterygidae) of the fauna of the USSR]. Tr.

Vsesoyuz. Entomol. Obshch. 56: 8-17.

|

J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), Dec. 31, 1977 27.

MORPHOLOGY OF ALIMENTARY AND REPRODUCTIVE
TRACTS OF THE RODENT BOT FLY, CUTEREBRA TENEBROSA
(DIPTERA: CUTEREBRIDAE)'

CRAIG R. BAIRD?

and

ROGER D. AKRE?

ABSTRACT

The internal reproductive and alimentary structures of Cuterebra
tenebrosa Coquillett were studied and compared to other calypterate flies.
Well defined mouth parts are present. Paired lingual salivary glands extend
horizontally almost to the abdomen; however, labial salivary glands were
not found. The alimentary canal is complete in female flies, whereas males
lack a crop. Females have three spherical spermathecae opening into the
upper portion of the genital chamber. Male reproductive structures are
similar to those in other flies. Tracheal air sacs fill one-third to one-half of

the abdomen.

INTRODUCTION

Little is known concerning the internal
structure of Cuterebra bot flies. Townsend
(1935) provided the earliest descriptions of
Cuterebra alimentary and reproductive tracts
but did not include illustrations.

In 1963, Catts described and illustrated the
alimentary and_ reproductive’ tracts of
Cuterebra latifrons Coquillett. A comparative
study of the alimentary canal of several flies
including C. latifrons was made by Singh and
Judd in 1966. Various authors have described
and illustrated the external genitalia of
Cuterebra (Bennett 1955; Haas & Dicke 1958;
Catts 1963; Graham and Capelle 1970; and
Baird and Graham 1973). The purpose of the
present paper is to report findings from
dissections of Cuterebra tenebrosa Coquillett
specimens and to provide illustrations of the
structures.

METHODS AND MATERIALS

Adult flies were obtained by rearing larvae
in captive bushytailed wood rats (Neotoma
cinerea Ord.). Within five days after emergence,
flies were injected with Kahle’s solution to kill
and fix them in an extended position. They
were stored in the same preservative for several
days and then transferred to 70% alcohol for
permanent storage. Dissections were performed
with standard insect dissection tools under a
binocular microscope.

‘Scientific Paper No. 4489, College of Agriculture Research
Center, Washington State University, Pullman. Project 994.3.

*Department of Entomology, University of Idaho, Moscow,
Idaho Address: P. O. Box 1058 Caldwell, Idaho 83605

*Department of Entomology, Washington State University,
Pullman, Washington 99163

OBSERVATIONS AND DISCUSSION

The use of Kahle’s solution to kill adult flies
proved a very useful technique since the
solution perpeated all body areas and preserved
the internal organs very well.

Alimentary Tract

No attempt was made to describe the mouth
parts of C. tenebrosa. The mouth parts are
typically muscoid in both sexes as described for
C. emasculator (Bennett 1955) and C. latifrons
(Catts 1963).

The paired racemose salivary glands are
connected anteriorly by a common salivary
duct which extends to the oral structures
(Figure 1). Posteriorly, the glands are situated

horizontally in the lower thorax and extend

almost to the abdomen. Catts (1963) reported
the salivary glands extending only into the
prothorax of C. latifrons. Singh and Judd
(1966), also working with C. latifrons found
salivary glands extending into the abdomen.
Townsend (1935) described salivary glands of
Cuterebra as being atrophied or absent. These
discrepancies may be due to age or to preser-
vation method.

Lowne (1890) and Hewitt (1914) indicated
that paired lingual salivary glands of Calliphora
and Musca, respectively, were of a simple
tubular type which ultimately terminated in the
posterior of the abdomen. Hori (1972) also
found tubular salivary glands extending into
the abdomen of flies belonging to eight
calypterate muscoid families. An additional
difference between Cuterebra and_ other
muscoid flies was that the labial salivary
glands present in Calliphora and Musca (Lowne
1890; Hewitt 1914) were absent in Cuterebra.

The alimentary canal in C. tenebrosa is
complete and basically similar to that in other
muscoid families. An important difference is
the apparent absence of a crop in male C.

28

J. ENTOMOL. Soc. Brit. CoLuMBIA 74 (1977), Dec. 31, 1977

AQ

He) dod [eIs1}S0A ‘AQ ‘yONp dois ‘QO ‘oes DeIPABd ‘SD ‘OBS DVIPID IO MOTA posiepUT °Z “By
winqoed ‘Y :se—nqny ueiysiydiey ‘LI :Snpnowquea ‘A ‘puets Arearpes ‘nS
‘a81}Ss0A dois ‘AQ ‘oes DVIPIeD ‘Gg :snseydose ‘Wy -esoiqoua} BIga19IND JO 49e1} ATeQUOUITY “[ “SI

G “SI

wil O°S
a
A 5S
N ee Oe
T 8d 4, &. Pe \

29

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>

Fig. 3. Female reproductive organs. O, ovary; AG, accessory gland; S, spermatheca; GC, genital
chamber

Fig. 4. Male reproductive organs. T, testis; VD, vas deferens; AG, accessory glands; ED, ejacula-
tory duct; A, aedeagus

c=
c="
Oo
met
ml
an)
iS)
co
=
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or)
re
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30 J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977:

tenebrosa specimens. Only one of five males
had a crop, whereas all four females had small
crops (Figure 1, Figure 2). Studies with
C. latifrons present conflicting results: Catts
(1963) reported a vestigal crop, whereas Singh
and Judd (1966) described a crop proportional
in size to that of other muscoid Diptera.

The ventriculus begins with a_ typical
cardiac sac. This organ is termed the proventri-
culus by Lowne (1890), Hewitt (1914),
Hori (1972), and the cardia by Singh and
Judd (1966). The remainder of the C. tenebrosa
ventriculus is tubular and of the same diameter
throughout. This agrees with findings for
C. latifrons by Catts (1963) and Singh and
Judd (1966). Food remnants were found in the
ventriculus and intestines of three male C.
tenebrosa specimens. This must certainly be
material held over from larval feeding since the
flies had no opportunity to feed as adults. At
the ventriculus-intestine junction, two
Malpighian ducts are present. Each duct gives
rise to two moniliform Malpighian tubules
which extend among the organs of the
abdomen. The rectum is similar in shape to that
of other flies; four rectal pads are present on
the anterior portion. Catts (1963) and Singh
Judd (1966) reported similar observations for
C. latifrons. Large tracheal air sacs extend from
one-third to one-half of the length of the
abdomen of C. tenebrosa. Townsend (1935)
made no mention of air sacs in his studies of
Cuterebra specimens.

Reproductive Tract

Figures 3 and 4 illustrate the internal
reproductive system of female and male
C. tenebrosa, respectively. They are similar to
descriptions of other Cuterebra provided by
Townsend (1935) and Catts (1963), although
C. tenebrosa females have spherical sperma-
thecae in contrast to the sausage-shaped
spermathecae of C. latifrons.

According to Hori (1972), the majority of
calypterate muscoid flies have three sperma-
thecae, although several genera’ within
Stomoxydinae (Muscidae) have but two. In the
lower flies, the number of spermathecae ranges

from zero to four. C. tenebrosa specimens have
spermathecae arranged one on the upper left
side of the genital chamber, one on top, and one
on the upper right side of the chamber (1:1:1).
In contrast, most other muscoid genera have
two left and one right (2:1) or one left and two
right (1:2) (Lowne 1890; Hewitt 1914; Hori
1972). A variety of spermathecal shapes were
illustrated by Hori (1972) for muscoid flies;
however, within genera the shapes were fairly
consistent.

C. tenebrosa males are basically similar to
other muscoid flies in the internal reproductive
structures. One difference between C. tenebrosa
and C. latifrons (Catts 1963) is that the
accessory glands are smaller in relation to the
testes in C. tenebrosa. This may be a function
of the age of the fly, however, as Hori (1972)
stated the shape of the testes of male muscoid
flies correlated closely to the age.

CONCLUSIONS

The alimentary tract of Cuterebra tenebrosa
is basically similar to other muscoid Diptera.
The two main differences are the reduced or
absent crop in males and the racemose salivary
glands in C. tenebrosa.

In early Cuterebra literature, these bot flies
were described as being without mouth parts.
Although more recent work has shown the true
nature of their mouth parts and alimentary
system, no one has reported Cuterebra flies
feeding or drinking. Apparently there is no food
requirement for oviposition. In rearing several
hundred Cuterebra flies in recent years, we have
maintained them from eclosion to oviposition
(usually five days) with no opportunity to feed.
In most cases the resulting eggs have had a
high fertility, although most females laid only
50-75% of their complement of eggs before
dying.

ACKNOWLEDGEMENTS
We wish to thank Mr. Al Greene, Washing-
ton State University for the figures. Dr. M. T.
James, Washington State University and
Dr. K. J. Capelle, Brigham City, Utah reviewed
the manuscript.

References
Baird, C. R. & C. L. Graham. 1973. Cuterebra tenebrosa: Description of immature stages and a

redescription of the adult (Diptera:

Cuterebridae) Can. Ent. 105:1281-1293.

Bennett, G. F. 1955. Studies on Cuterebra emasculator Fitch 1856 (Diptera: Cuterebridae) and a
discussion of the status of the genus Cephenemyia Ltr. 1818. Can. J. Zool. 33: 75-98.

Catts, E. P. 1963. The biology of Cuterebra latifrons Coquillett (Diptera:

Cuterebridae). Ph.D.

Dissertation, University of California, Berkeley. 174 pp. (unpub.)

Graham, C. L. & K. J. Capelle. 1970. Redescription of Cuterebra polita (Diptera:

Cuterebridae)

with notes on its taxonomy and biology. Ann. Entomol. Soc. Amer. 63: 1569-1573.

Haas, G. E. & R. J. Dicke. 1958. On Cuterebra horripilum Clark (Diptera:

Cuterebridae) parasiti-

zing cottontail rabbits in Wisconsin. J. Parasitol. 44:527-540.
Hewitt, C. G. 1914. The House Fly, Cambridge University Press, London. 195 pp.

J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977 31

- Hori, K. 1972. The works of the late Dr. Katshushige Hori. Comparative anatomy of the internal

organs of the calypterate muscoid flies and the other works. Kanazawa, Japan. 306 pp.
Lowne, B. T. 1890. The anatomy, morphology, and development of the blowfly (Calliphora

erythrocephala) I. Porter, London.

Singh, S. B. & W. W. Judd. 1966. A comparative study of the alimentary canal of adult calypterate
Diptera. Proc. Entomol. Soc. Ont. 96:29-80.

Townsend, C. H. T. 1935. Manual of myiology, Part II Muscoid classification and habits.

Townsend Pub., Sao Paulo, Brazil.

EURRHYPARA HORTULATA L. (URTICATA L.) ON THE
PACIFIC COAST (LEPIDOPTERA: PYRALIDAE)

This attractive little moth, which can hardly
be confused with anything else in the North
American fauna, is native to Europe and
temperate east Asia. It ranges from Ireland to
the Amur-Ussuri region and Manchuria. It
was established in Nova Scotia by 1907 at
MacNab’s Island and Truro. At present it has
a wide range in the Northeast, extending from
Newfoundland to Ontario and southward. The
moth flies mainly in July, at night, is attracted
to light and in the daytime is easily flushed.
The main food-plant in Europe is _ nettle,
Urtica dioica L., and other plants such as
Marrubium vulgare L., Stachys sp., Mentha
sp., Calystegia sepium Br. and Ribes sp.
Probably it has other plant hosts also. Little
is known about its food plants in North
America.

Until now there were no records of E.
hortulata having been collected on the Pacific
coast. There are no specimens from this area in
local collections or in the Canadian National
Collection at Ottawa.

On 18 June, 1977 a perfect female specimen
was seen resting on the ceiling of a living room
in East Vancouver. It was in such immaculate
condition that it was obvious that it was
freshly emerged. Unfortunately, in my excite-
ment, the specimen was somewhat damaged

during capture. Four days later, another
perfect specimen, a male, was flushed in the
garden and collected. Another was observed
in the garden on 23, 26 and 27 June but no
further specimens were collected in order to
give the species a chance to survive and become
established in Vancouver. How the moth
arrived in Vancouvr will remain a mystery.
Most likely the first specimens were introduced
last year, deposited eggs and produced moths
this year. The host-plant here remains
unknown. There are no nettles growing in the
vicinity and the nearest place known to me
where nettles grow in Vancouver is near the
seawall in Stanley Park. There are other
possible plant hosts, however, cultivated in our
garden, such as Stachys recta, at least three
different species of Mentha, Calystegia sepium
and Ribes sp. The moth may have selected one
of those plants on which to lay eggs.

In Europe the larva rolls the leaves or spins
them together. The cocoon is spun in a
sheltered place, usually under the bark, in
autumn. Hibernation takes place as a prepupal
larva which pupates in the spring. There is one
generation per year. Next June or July should
show whether the moth will establish itself in
Vancouver or not. Unlike horticulturists and
the Plant Protection Division, I hope it will.

References
Beirne, B.P. 1952. British Pyralid and Plume moths. London & New York.
Forbes, W. T. M. 1923. Lepidoptera of New York and neighbouring States. Part I, Ithaca.
Meyrick, E. 1968. A Revised Handbook of British Lepidoptera.
Munroe, E. 1976. Pyralidae. Pyraustinae. Pyraustini. The Moths of America North of Mexico.

fasc. 13.2A.

W. Lazorko

o2 J. ENTOMOL. Soc. BRIT. COLUMPIA 74 (1977), DEc. 31, 1977

EFFECT OF ANTI-AGGREGATIVE PHEROMONES 3,2-MCH
AND TRANS-VERBENOL ON DENDROCTONUS RUFIPENNIS

ATTACKS ON SPRUCE STUMPS |
E. D. A. DYER AND P. M. HALL

Canadian Forestry Service
Pacific Forest Research Centre
Victoria, B.C.

Department of Fisheries and the Environment

ABSTRACT

Anti-aggregative pheromones 3,2-MCH and 3,2-MCH with trans-
verbenol were released from open vials enclosed in perforated cans attached
to both sides of 50 winter-cut spruce stumps which normally attract spruce
beetles (Dendroctonus rufipennis). Although significantly fewer attacks
occurred on treated than on untreated stumps, the attack density was not
sufficiently reduced to be of practical value in controlling spruce beetle
reproduction in this host material. There was no significant difference in
reduction of beetle attacks between the 3,2-MCH and the 3,2-MCH with
trans-verbenol treatments.

RESUME

On a libere a partir de fioles ouvertes placées a |’intérieur de canettes
perforées, attachées aux ‘‘deux cOtés” de 50 souches d’Epinette coupees en
hiver, des pherormones anti-agglomerantes 3, 2-MCH et 3, 2-MCH avec
trans-verbenol et qui normalement, attirent de Dendroctone de |’Epinette
(Dendroctonus rufipenns). Malgré un nombre significativement reduit
d’attaques contres les souches traitees, comparativement aux autres
souches, la densité de |’infestation ne fut pas suffisamment diminuee pour
constituter un moyen pratique d’enrayer la reproduction du Dendroctone
de l’'Epinette dans cet arbre hote. I] n’y eut pas de differénce significative
dans la baisse des attaques du Dendroctone entre les traitements 3, 2-MCH

et 3, 2-MCH avec trans-verbenol.

INTRODUCTION

The spruce beetle, Dendroctonus rufipennis
(Kirby), occurs throughout the range of spruce
in Canada and the United States (Wood, 1963).
At epidemic levels, it attacks and kills large
volumes of mature standing spruce (Picea
engelmannii Parry, P. glauca (Moench) Voss),
and at endemic levels, it breeds principally in
fresh spruce windfall, stumps and slash.

3,2-MCH (°-methyl-2-cyclohexen-1-one),
an anti-aggregative pheromone produced by
the Douglas-fir beetle, Dendroctonus pseudotsu-
gae Hopk., has been shown to mask the effect of
the aggregative pheromones of this beetle
(Rudinsky et al., 1972). Other experiments with
this pheromone applied to spruce logs have
shown a similar anti-aggregative effect to
spruce beetles (Rudinsky et al., 1974; Kline
et al., 1974). A second pheromone, trans-
verbenol (trans- 4, 6, 6-trimethylbicyclo -
(3-1-1) -3-hepten-2-ol), is the principal aggrega-
tive pheromone of the mountain pine beetle,
Dendroctonus ponderosae Hopk. (Pitman and
Vité, 1969), but is an _ anti-aggregative
pheromone component of the western pine
beetle, Dendroctonus brevicomis Lec. (Wood,
1972). Results of experiments on the effect of

trans-verbenol on Douglas-fir beetle are
unclear; comparable experiments have given
both aggregative and anti-aggregative results
(Rudinsky et al., 1972). Furniss et al. (1976)
stated that trans-verbenol repressed attraction
of spruce bettle to logs with and without the
synthetic attractants frontalin and seudenol,
but that its effect was less than that of 3,
2-MCH.

An experiment to determine the anti-
agegregative effect of 3,2-MCH and 3,2-MCH
with trans-verbenol on spruce beetle was
carried out during the spring and summer of
1975, using attractive spruce stumps in a
winter clearcut area in central British
Columbia.

METHODS

Twenty 5-stump groups, in 10 pairs with
approximately 50 m between groups in each
pair, were selected throughout a large clear-
cut area and treated as follows: 10 groups, one
of each pair, were designated as controls and
left untreated; the other 10 groups were
alternately treated with 3, 2-MCH alone or with
3, 2-MCH and trans-verbenol. Closed perfora-
ted film cans, each containing an open 0.5 dr
vial with 0.1 ml 3, 2-MCH (Rudinsky et al.,

CE TTT IIE

J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977 33

1972), were placed on the centers of the north
and south sides of each treated stump. For
each stump treated with both 3, 2-MCH and
trans-verbenol, a second open 0.5 dr. vial con-
taining 0.15 ml of trans-verbenol was put in
each can with the 3, 2-MCH. Vials were checked
for evaporation throughout the flight period to
ensure the presence of the two chemicals.

Stumps were treated by May 29 and left
throughout June, the beetle flight period.
After flight, six 10.16-cm-diameter bark
samples were cut randomly from the north
lower side of each stump. The number of
entrance holes was counted on each sample
and totalled for all samples in all stumps of
each group. A randomization test for matched
pairs (Siegel, 1956) was used to compare the
3,2-MCH-treated stumps to their respective
controls, and 3,2-MCH_ + _ trans-verbenol
treated stumps to their respective controls.
Differences between treated and control pairs
were calculated for each of the 3,2-MCH and
3,2-MCH - trans-verbenol groups, and the two
treatments were compared to each other, using
a randomization test for two independent
samples (Siegel, 1956).

RESULTS AND DISCUSSION

The emission of 3,2-MCH alone and that of
3,2-MCH_ and/trans-verbenol at attractive
spruce stumps resulted in a reduction in the
number of beetle attacks compared to attacks
on untreated stumps, although only two of the
10 treated replicates were not attacked
(Table 1). The addition of trans-verbenol to
3, 2-MCH made no significant difference to the
degree of reduction in the number of attacks.

The emission of 3, 2-MCH at spruce stumps
produced a 50% reduction in attack density,
with a spacing of less than 1 m between 3,
2-MCH containers on _ individual stumps.
Rudinsky et al. (1974) used a 1.8 m spacing
between 3, 2-MCH containers on downed spruce
trees and achieved complete protection from
attacks. Since the north aspects of the spruce
stump bases are the most productive areas
for spruce beetle brood in logging slash (Dyer
and Taylor, 1971), the reduced attack density
on 3, 2-MCH-treated stumps is not low enough
to ensure population reduction in the next
generation. The lower density broods would
reduce competition and _ thereby possibly
increase survival to maturity under suitable

TABLE 1. Spruce beetle attacks/m? from 600 samples on north sides of 100 stumps with two
treatments and paired controls.

3, 2-MCH
TREATMENT

CONTROL

3,2-MCH + trans verbenol
TREATMENT CONTROL

‘differs from paired control @ 0.125 level of significance.
*differs from paired control@0.05 level of significance. No difference between MCH and
MCH + trans-verbenol @ 0.05 level of significance.

environmental conditions. The _ difference
between the reduction of attack on spruce
stumps and that on downed trees may be due
to the difference in environmental exposure
around the treated material. Open logging
slash, with greater air movement and higher
temperatures, would tend to disperse the

3, 2-MCH faster than in a more sheltered stand
environment, thereby producing a lower con-
centration of 3, 2-MCH at the source.

Therefore, 3,2-MCH apparently cannot be
applied by this method as a practical means of
reducing spruce beetle populations breeding in
suitable logging slash.

References
Dyer, E. D. A. and D. W. Taylor. 1971. Spruce beetle brood production in logging slash and wind-
thrown trees in British Columbia. Information Rept. BC-X-62. Can. Dept. Env., Pac. For.

Res. Centre, Victoria, B.C.

Furniss, M. M., B. H. Baker and B. C. Hostetler. 1976. Aggregation of spruce beetles (Coleoptera)
to seudenol and repression of attraction by methylcyclohexenone in Alaska. Can. Ent.

108: 1297-1302.

Kline, L. N., R. F. Schmitz, J. A. Rudinsky and M. M. Furniss. 1974. Repression of spruce
beetle (Coleoptera) attraction by methylcyclohexenone in Idaho. Can. Ent. 106: 485-491.

Pitman, G. B. and J. P. Vité. 1969. Aggregation behavior of Dendroctonus ponderosae (Coleoptera:
Scolytidae) in response to chemical messengers. Can. Ent. 101: 143-149.

34 J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977 |

Rudinsky, J. A., M. M. Furniss, L. N. Kline and R. F. Schmitz. 1972. Attraction and repression of |
Dendroctonus pseudotsugae (Coleoptera: Scolytidae) by three synthetic oo |

traps in Oregon and Idaho. Can. Ent. 104: 815-822.

Rudinsky, J. A., C. Sartwell, Jr.,

T. M. Graves and M. E. Morgan. 1974. Granular formulation of |
methylcyclohexenone: an antiaggregative pheromone of the Douglas-fir and spruce bark |

beetles (Col., Scolytidae). Z. ang. Ent. 75: 254-263.
Siegel, S. 1956. Non parametric statistics. McGraw-Hill Book Co. Inc., New York. 312 pp.

Wood, D. L. 1972. Selection and colonization of ponderosa pine by bark beetles. In: Insect/ Plant

Relationships; ed: H. F. van Emden. Symp. Roy. Entomol. Soc. (London) 6, 101-117.
Wood, S. L. 1963. A revision of the bark beetle genus Dendroctonus Erichson (Coleoptera:

Scolytidae). Gt. Basin Nat. 23: 117 pp.

INSECTS COLLECTED FROM AN ALPINE-SUBALPINE REGION
IN SE BRITISH COLUMBIA

J. HARLING', J. M. SNYDER? AND D. M. COLETTI?

Department of Biological Sciences
Notre Dame University
Nelson, B.C.

ABSTRACT

Insects were caught in a subalpine area of southeastern British Colum-
bia. The list consists of 23 spp. and 37 genera, in families of five orders. The
insects were collected during July and August, 1975 as part of a larger
study of the ecology of mountain caribou in the Poplar Creek area, north of

Nelson, B.C.

INTRODUCTION

There are few identified collections of
insects in the alpine-subalpine environment of
British Columbia. This is a report on insects
collected in the central Selkirk Mountains of
British Columbia during July and August 1975.
The paper by Allan (1969) is most similar to the
present report, although his collections were
mainly from lower elevations and limited to the
family Syrphidae. Other related studies, but
not from British Columbia, include those of
Chapman (1954), Dodge and Seago (1954) and
Mani (1955).

The insects reported here were obtained
during a survey for potential pests of mountain
caribou (Rangifer tarandus montanus) inhabi-
ting the alpine-subalpine environment at the
same time of the year. The caribou is the
subject of a study by Harling and Snyder
(unpublished).

METHODS AND STUDY AREA

The insects were sampled between 10 July

and 27 August, 1975 with pieces of wire screen

‘Present address:
Okanagan College
1000 KLO Road
Kelowna, B.C.

*Selkirk College
Castlegar, B.C.

‘Department of Biological Sciences
Simon Fraser University
Burnaby, B.C.

(40x50 cm), smeared with grease and placed
on supports about 0.9 m above ground level.
Additional collections were made with hand

|
|
|
|
|
|
|

|

nets and a Malaise trap. The insects were first |
identified in the laboratory and the identifica- —
tions verified by the Biosystematics Research ©

Institute, Canada Department of Agriculture,
Ottawa, Ontario.

General meteorological data were obtained |

from maximum and minimum thermometers, a
sling psychrometer, and a simple rain gauge;
wind speed and direction were estimated at the
time when samples were collected from the
traps.

The collection was mainly from the extreme |

north fork at the west end of the headwaters

of Poplar Creek (50° 21’ N, 117° 21’ W) in ©
southeastern British Columbia. The area com- ©
prised alpine meadows, talus slopes, receding |
snow patches and the upper fringe of climax ©

stands of englemann spruce (Picea englemanni)

and subalpine fir (Abies lasiocarpa). The collec- —
tions were made between 1500 and 1650 m >

elevation.
RESULTS

Table I lists the insects collected during the
study. Only those taxa verified by the Bio-
systematics Research Institute have been
included. Dipterans alone made up about 78%
of the catch. The families Bibionidae, Syrphi-
dae, Tabanidae and Tipulidae comprised more
than 50% of all the Dipterans caught. Hemip-

_J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977 ao

Table 1. Insects collected from the Poplar Creek area of SE

British Columbia, July and August, 1975.

COLEOPTERA

DIPTERA

HEMIPTERA

HYMENOPTERA

Buprestidae Agrilus sp.
Melanophila drummondi(Kby.)
Cantharidae Podabrus scaber (LeC.)
Carabidae Phloeopterus sp.
Cerambycidae Anoplodera aspera (LeC.)
Xylotrechus longitarsis (Csy.)
Chrysomelidae Chryomela sp.
Syneta subalpina (Edwards)
Coccinellidae
Elateridae Ctenicera hoppingi (Van Dyke)
Ctenicera sylvatica (Van Dyke)
Lycidae Dictyopterus sp.
Scarabeidae Aphodius sp.
Scolytidae Orthotomicus sp.
Trypodendron lineatum (Oliv.)
Cryphalini
Scraptiidae Anaspis sp.
Staphylinidae Ptomaphagus sp.
Omaliinae
Anthomyiidae Hylemya sp.
Hylemya (Pegohylemia) fugax (Meigen)
Hylemya (Botanophila) spinidens (Malloch)
Bibionidae Bibio sp.
Calliphoridae Phormia regina ( Mg.)
Drosophilidae Clastopteromyia inversa (Walker)
Empididae Drapteris sp.
Empis brachysoma (Coquillett)
Tachydrominae
Muscidae Lasiops medius (Stein) “
Rhagionidae Symphoromyia atripes (Bigot)
Syrphidae Chrysotoxum sp. o
Melangyna sp. &
Syrphus torvus (O.S.) 3
Tabanidae Hybomitra osburni ( Hine)
Tachinidae Nowickia pilosa
Tipulidae
Limoniinae
Tipulinae
Miridae Irbisia nigripes (Kgnt)
Lygus varius (Kgnt)
Bombidae Pyrobombus (Pryrobambus) flavifrons flavifrons (Cresson)
Colletidae Hylaeus sp.
Siricidae Urocerus gigas flavicornis (F.)
Tenthredinidae Tenthredo sp. ,
Dolerus (Dolerus) sp.
Pamphiliidae Pamphilius sp.

LEPIDOPTERA

Nymphalidae

Boloria epithore (Edwards)

36 J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), Dec. 31, 1977 |

terans and Lepidopterans each comprised less
than 2% of the total; Coleopterans and
Hymenopterans represented the rest.

The temperature during the study ranged
from 3.4°C to 23.9°C with humidity from
43-88%. The maximum precipitation recorded
on a sampling day was 0.48 cm and on other
days was often zero. Wind speed varied from
force 0 to force 2 and was usually from the
south.

Catches were largest during periods of high
temperature, low precipitation, and _ low
humidity. No clear trend was noted with refer-
ence to wind speed or direction. Other authors
(Chapman, 1954; Mani, 1962) have confirmed
that the meteorological factors recorded here
do have a marked effect on insect activity
at high elevations.

DISCUSSION

At least an additional 25 species were
caught but were not identified by the Bio-
systematics Research Institute because they
were damaged in transit.

The methods employed in this investigation
were relatively simple, so that the analysis of
relative abundance could not be sophisticated.
However, the predominance of Dipterans in
relation to other groups was significant and
consistent with other surveys of alpine insect
fauna (Chapman, 1954; Dodge and Seago,
1954; Mani, 1955, 1962). Among families, the

Syrphidae and Tabanidae were abundant as_

also reported by Chapman (1954) but the

Tachinidae which he found to be abundant were |

represented here by a single specimen.

A number of the Dipteran species listed in
Table I may be associated with the caribou |

population of the area. In particular, the blow-
fly (Phormia regina (Mg.) ) and the tabanid

(Hybomitra osburni (Hine) ) could be potential |

caribou pests because related genera have been
confirmed as large mammal pests (Prior, 1968).
Bot and warble flies parasitize caribou
(Bergerud, 1961; Low, 1964; Layser, 1974)
and although no such species were recorded in
our samples, a close relative (the tachinid
Nowickia pilosa) was caught. The mountain
caribou continue to be studied in the area and

it is hoped that some confirmation of their |

insect pests will be forthcoming.
ACKNOWLEDGEMENTS

The authors thank the National Research |

Council of Canada for grants to J. Harling and
J. M. Snyder for their study on the ecology of
the mountain caribou of which the work repor-

ted here was a small part. We are also grateful ©
to the Professions for Tomorrow Programme of |
the B.C. Department of Labour for funding to |

employ student assistants during the summer
of 1975. Finally, we thank the staff of the Bio-
systematics Research Institute, Ottawa,
Ontario for verifying the identifications.

References
Allan, D. A. 1969. Syrphidae collected mostly in southern areas of the Okanagan Valley, British
Columbia. J. Entomol. Soc. Brit. Columbia 66: 19-21.

Bergerud, A. T. 1961. The reproductive season of Newfoundland caribou. (Unpublished) 31 pp.
Chapman, J. A. 1954. Studies on summit frequenting insects in western Montana. Ecology 35: |

41-49.

Dodge, H. R. and J. M. Seago. 1954. Sarcophagidae and other Diptera taken by trap and net on
Georgia mountain summits in 1952. Ecology 35: 50-59.

Layser, E. F. 1974. A review of the mountain caribou of northeastern Washington and adjacent
northern Idaho. J. Idaho Acad. of Science, Special Res. Issue. No. 3. 63 pp.

Low, W. A. 1964. A general ecological study of mountain caribou in Tweedsmuir Provincial Park |
(Unpublished report of work supported by the University of British Columbia and the

B.C. Fish and Wildlife Branch). 4 pp.

Mani, M. S. 1955. Entomological survey of the Himalaya, Pt. IV - Expedition to the Upper Chenab
Valley, 1954. Agra Univ. J. Res. (Sci.) 4: 157-170.

Mani, M. S. 1962. Introduction to high altitude entomology. Methuen, London. 302 pp.
Prior, R. 1968. The Roe Deer of Cranbourne Chase. Oxford University Press. 222 pp.

_ J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977 37

OVERWINTERING SURVIVAL OF PISSODES STROBI (PECK)
(COLEOPTERA: CURCULIONIDAE) IN SITKA SPRUCE
LEADERS?

T. J. D. VANDERSAR?

Pestology Centre
Department of Biological Sciences
Simon Fraser University
Burnaby, B.C. V5A 1S6

Across most of its range, Pissodes strobi
Peck’ overwinters as an adult in the duff at the
base of brood hosts from which it emerged in
autumn (Belyea and Sullivan 1956; Stevenson
1967). On the west coast of British Columbia,
mild winters apparently permit adult P. strobi
to overwinter on the bole and laterals of Sitka
spruce (Gara, Carlson, and Hrutfiord 1971;
McMullen and Condrashoff 1973). Silver (1968)
suggested that although some P. strobi in
coastal B.C. overwinter as larvae in_ host
leaders, they may be unable to complete their
development the following spring.

On June 8, 1976, I collected 26 Sitka spruce
leaders attacked in 1975 from two plantations
near Port Renfrew, Vancouver Island. These
terminals were maintained in the laboratory at

‘Research supported by a Canadian Forestry Service Science
Subvention Grant, The National Science Foundation, U.S.A.
(Grant No. GB-15959), and the National Research Council,
Canada (Grant No. A3881).

*Graduate student.

Smith and Sugden (1969) designated the former Sitka
spruce weevil, Pissodes sitchensis Hopkins and the Engelmann
spruce weevil, P. engelmanni Hopkins, as ecotypes of P. strobi
Peck on the basis of morphological and cytogenetic similarities
(Manna and Smith 1959; Smith 1962).

approximately 20°C. Sixteen adult P. strobi
(9¢¢ and 7292) emerged during a 2-week
period in late June. Five additional male
weevils emerged in late July, from Sitka spruce
leaders collected at the same sites on July 7,
1976.

After a count of weevil emergence holes
chewed through the intact outer bark, the
leaders from the June 8, 1976 collection were
dissected. A total of 737 chip cocoons in the
xylem and pith contained 36 dead adults
(4.9%) that had failed to emerge. An additional
75.3% had apparently died in chip cocoons prior
to completing pupation. The count of
weathered emergence holes indicated that 130
adults (17.6%) had emerged in late summer to
fall, 1975. The 16 P. strobi that emerged in
early summer, 1976 constituted 2.2% of the
total chip cocoon population or 11.0% of the
total emergent population.

These results indicate that P. strobi can
successfully overwinter in the larval stage in
Sitka spruce leaders in coastal B.C.

Acknowledgements

I thank W. Coombs for allowing me to
collect weevils on plantations managed by
B.C. Forest Products Ltd., N. Yalpani for
assistance with field work, and Dr. J. H.
Borden for review of the manuscript.

References
Belyea, R. M. and C. R. Sullivan. 1956. The white pine weevil; a review of current knowledge. For.

Chron. 32: 58-67.

Gara, R. I., R. L. Carlson, and B. F. Hrutfiord. 1971. Influence of some physical and host factors
on the behaviour of the Sitka spruce weevil, Pissodes sitchensis, in southwestern
Washington. Ann. Ent. Soc. Am. 64: 467-471.

Manna, G. K. and S. G. Smith. 1959. Chromosomal polymorphism and inter-relationships among
bark beetles of the genus Pissodes Germar. The Nucleus 2: 179-208.

McMullen, L. H. and S. F. Condrashoff. 1973. Notes on dispersal, longevity, and overwintering
of adult Pissodes strobi (Peck) (Coleoptera: Curculionidae) on Vancouver Island. J. Ent.

Soc. B.C. 70: 22-26.

Silver, G. T. 1968. Studies on the Sitka spruce weevil, Pissodes sitchensis, in British Columbia.

Can. Ent. 100: 93-110.

Smith, S. G. 1962. Cytogenetic pathways in beetle speciation. Can. Ent. 94: 941-955.

Smith, S. G. and B. A. Sugden. 1969. Host trees and breeding sites of native North American
Pissodes bark weevils, with a note on synonymy. Ann. Ent. Soc. Am. 62: 146-148.

Stevenson, R. E. 1967. Notes on the biology of the Engelmann spruce weevil, Pissodes engelmanni
(Curculionidae: Coleoptera) and its parasites and predators. Can. Ent. 99: 201-213.

38 J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), Dec. 31, 1977 |

A NEW CLASTOPTERA FROM SAGEBRUSH (RHYNCHOTA:
HOMOPTERA: CERCOPIDAE)
K. G. A. HAMILTON

Biosystematics Research Institute
Agriculture Canada, Research Branch
Ottawa, Ontario

ABSTRACT

J. Ent. Soc. B.C.

Clastoptera atrapicata n. sp. (Homoptera: Cercopidae) is described from
sagebrush (Artemisia tridentata Nutt) in central British Columbia and
Oregon. This species is closely allied to C. brunnea Ball, and, like it, exhibits
considerable variation in colour pattern of the face. The ovipositor and
colour varieties are illustrated and compared with those of its related

species.

The genus Clastoptera in America north of
Mexico was revised by Doering (1928) to
include 29 species. Of these, six were distinc-
tive in having fewer pronotal striae (10 or
fewer on midline) than the other species, and in
having ~~ arid-adapted _hosts: sagebrush
(Artemisia tridentata Nutt) and rabbit brush
(Chrysothamnus spp.). Two of these six, sierra
Doering and binotata Ball, are wholly black in
both sexes; one, delicata Uhler, is yellow with
black pronotal bars in both sexes; and in the
remaining three, the males are black and the
females are yellow with black pronotal bars. To
the latter group I now add a fourth previously
unrecognized species.

Clastoptera atrapicata n. sp.
(Figs. 7-10, 12, 16, 17)

Body form as in other Clastoptera, but with
frons considerably inflated, tylus longer than
median length of vertex in both sexes, in dorsal
aspect with tylus appearing about as long as
median length of vertex (Fig. 12). Length:
male, 2.9-3.5 mm; female, 3.2-4.2 mm.

Male. Colour blackish-brown except for pale
areas on tegmina around bullae, yellow spot at
centre of costa, and yellow spots on lora;
similar to C. brunnea Ball in colour. Male
genitalia as in brunnea (Doering 1928, pl. XXV,
fig. 3).

Female. Colour pale yellow, overlaid with
two heavy black bars across fore margin of
pronotum and between eyes, and finer brown
lines (6-9 in number) across pronotum; face
variously marked with fuscous and_ black
(Figs. 7-10); tegmina mottled with fuscous,
paler on apical cells and along edge of trans-
verse creases; legs pale, banded with fuscous;
similar to brunnea in colour.

Inner rami of ovipositor parallel-margined
on basal half, strongly tapered apically, ventral
margin curved dorsad, dorsal margin straight,
armed with two close-set teeth near midlength
(Figs. 16, 17); similar to ovipositor of C. lugu-
bris Ball.

Types. Holotype? , Seton L., Lillooet, B.C.,

=.

SS

ie a

—S

30 June 1926 (J. McDunnough) on sagebrush. |

Paratypes: 14¢4¢, 629, same data as holotype;

5336, 1392, 17 mi SE Spences Bridge, B.C., |

8 Aug. 1976 (K. G. A. Hamilton) on sagebrush;
13, SE slope Glass Butte, 12 mi E Hampton,
Lake Co., Ore., 12 July 1968 (J. D. Lattin)
68-27; 12 , 14 mi N Burns, Harney Co., Ore., 14
Aug. 1971 (P. W. Oman). Holotype and 38
paratypes no. 14073 in the Canadian National
Collection, Ottawa; 2 paratypes in the collec-
tion of Oregon State University, Corvallis.

Remarks. C. atrapicata is closely allied to
brunnea Ball, lugubris Ball and lineatocollis
Stl. Males of atrapicata may be distinguished
from all three by the more strongly inflated
frons and longer tylus (Fig. 12). In dorsal
aspect the tylus appears to be as long as the
vertex, while in the three allied species the
tylus appears half as long (Fig. 11). Males of
lugubris and lineatocollis also have more exten-
sive pale markings on the face (Doering 1928,
pl. IV, fig. 2a).

Females of lugubris differ from those of
atrapicata, brunnea and lineatocollis in their
larger size (3.6-4.6), in having the tylus very
strongly produced, in dorsal aspect longer than
the vertex, and in having the pronotal bars of
equal width and darkness with the interocular
bar.

Females of atrapicata can be distinguished
from those of all its other relatives by the shape
of the apex of the inner rami of the ovipositor,
and by the placement of the ovipositor teeth
near the centre of the blade (Figs. 16, 17). The
facial markings of atrapicata are also distinct:
the base of the clypellus always has a pale
transverse band (Figs. 7-10) not found in
brunnea and lineatocollis (Figs. 1-6); further-
more, the majority of specimens have the upper
half of the frons black (Figs. 7-8), a condition
not found in related species. The variability
of the facial markings show the close relation-
ship between brunnea and atrapicata.

:

| J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977

5
M4 ™
Seats
Gece
seatees
Ant
Me eats
oO wote.®,
\
4 Fj 4 ~
r A ara «
ee Wr a)
LPs e

|

Figs. 1-10. Facial patterns in Clasptoptera species. 1-5, C. brunnea Ball; 6, C. lineatocollis Stal;
7-10, C. atrapicata n. sp.

39

40 J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), Dec. 31, 1977
aun, ai

ear
ote Se)

Figs. 11-12. Profile of head and pronotum of Clastoptera species with apparent extent of frons and |
vertex from dorsal aspect indicated by arrows. 11, C. brunnea; 12, C. atrapicata. |
Figs. 13-18. Ovipositor blades of Clastoptera species, lateral aspect. 13, 14, C. brunnea; 15, C. |
lineatocollis; 16, 17, C. atrapicata; 18, C. delicata Uhler.

J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977 41

ACKNOWLEDGEMENTS

I wish to thank Dr. P. W. Oman of Oregon
State University, Corvallis for loan of speci-

mens of Clastoptera for comparison with those
deposited in the Canadian National Collection.

Reference
Doering, K. C. 1928. The genus Clastoptera in America North of Mexico. Kans. Univ. Sci. Bull.

18 (1): 5-153.

PTEROSTICHUS STRENUUS PANZ,
A NEWLY-DISCOVERED PALAEARCTIC SPECIES IN THE
VANCOUVER AREA (COLEOPTERA: CARABIDAE)

There are about 17 species of palaearctic
Carabids known to be introduced from Europe
into British Columbia, largely to the Vancouver
area. Most were known for some time but some
were discovered only recently. Lindroth (1957),
in his excellent treatise on faunal connections
between Europe and North America, postulated
that practially all of those species were intro-
duced with ship’s ballast (Scudder 1958). An
attempt is being made by the Entomological
Society of Canada in its Biological Survey Pro-
ject to collect all the available data on the distri-
bution of introduced Carabidae in this province.
I hope to compile a detailed list of the species
with their known places of occurrence in the
near future. Thus, this note may be of interest.

To the list of introduced species compiled
from Lindroth’s monograph (1963-1969) and
supplemented by my own collecting and obser-
vation during the past 29 years I am able to

add Pterostichus strenuus Panz., which has
been taken recently in Vancouver.

The first specimen, a female, was collected
on 8 June, 1968 on the marshy edge of a ditch,
close to Beaconsfield Park in East Vancouver.
All attempts to collect more specimens at the
time were unsuccessful. Three more specimens,
a male and two females, were collected by Prof.
G. G. E. Scudder of UBC on 21 August, 1973
in a marshy area at the foot of Olympic Street
in Vancouver (UBC Coll.). These specimens are
at present the only records from the Pacific
Coast of North America.

Pterostichus strenuus is distributed through
the whole northern Palaearctic. In North
America it has been known since 1937, restric-
ted to a small area of southeastern Newfound-
land, where it is a species of open, moderately
moist grassland, often close to the sea
(Lindroth, 1955). In Vancouver it appears to be
more hygrophilous and less common.

References
Lindroth, G. H. 1955. The Carabid beetles of Newfoundland. Lund.

Lindroth, C. H. 1957. The faunal Connections between Europe and North America. New-York-

Stockholm.

Lindroth, C. H. 1963-1969. The ground-beetles (Carabidae, excl. Cicindelinae) of Canada and

Alaska. Lund.

Scudder, G. G. E. 1958. A new aspect on the faunal connections between Europe and the Pacific
Northwest. Proc. Ent. Soc. of B.C. Vol. 55 p. 36. .

W. Lazorko

42 J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977 |

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J. ENTOMOL. Soc. Brit. COLUMBIA 74 (1977), DEc. 31, 1977

43

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JOURNAL

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ENTOMOLOGICAL

_—s- SOCIETY of
_ BRITISH COLUMBIA

Issued December 31, 1978

ECONOMIC
INSON, BROWN, FINLAYSON, WILLIAMS & MacKENZIE—Furrow
application of insecticide as a method of controlling wireworms
MNES Be atees kaa aihs s Si Miles a wianigs Wheto oe, Wy leis Je Wwe 6S ele bid ob .0 Biase eee ee 3
S, EVERSON & THEAKER—Ffficacy of insecticides against
eometrid larvae, Opheroptera spp., on southern Vancouver
EEMSUTOMUNNDED 0 oa wk 6 oe os dsc cic ckecce cc aeecessieccvccvecees 6
i—The effect of root weevils (Coleoptera: Curculionidae) on yield
five strawberry cultivars in British Columbia...................00ccececece 10
GENERAL
ERSAR—Emergence of general predator and parasites of the white
weevil, Pissodes strobi (Coleoptera: Curculionidae), in
igelmann ss he VE, soe ate diva w oid Siete mode wise ewe es 14
INGS—The distribution of Tanypteryx hageni (Odonata:
taluridae) MT CMIS EIR ER os 0 co ek eile Se as Whar Seas veaceccecsivecs 18
'ON—The mosquitoes of Burnaby Lake, British Columbia..................-- 20

ANLAR & BEIRNE—Fruit tree leafrollers (Lepidoptera) and
I asites (Hymenoptera) introduced in the Vancouver

A OWN & KULHAVY —Egg dispersion in the larch casebearer,
é Coleophora laricella hg Sei seed in Northern Idaho............ 27

western larch in Northern Idaho... ......... cc ccc cece cece et ceeccesceeeees 29

DLIN & RUTH—Examination of Douglas-fir clones for

differences in susceptibility to damage by cone and seed insects..............22. 33
AKI, OLSEN & GUPTA—Laboratory evaluation of Geocoris

bullatus and Nabis alternatus as predators of Lygus.............cceecececees 35
RSON—Buprestidae of southern Vancouver Island .................cceeeeees 38

TAXONOMIC
PPNER—Eutromula pariana (Clerck) (Lepidoptera: Choreutidae), the
correct name of the apple-and-thorn skeletonizer .............. ccc cee cece ees 40

CE & SCUDDER—Larval taxonomy and distribution of
rris pingreenensis and G. incognitus (Hemiptera:
SM ATE PATIO COMEINONG 565 oe ee rie Selina Ws cube ene ae eeeubecsecaes 41

_ of British Columbia 5. Name changes .............. 0. ec es ec rec ec ene eeeneees 45

RBES & CHO-KAI CHAN—The aphids (Homoptera: Aphididae)

British Columbia 6. Further additions ...............cccccccccccccceccecs 47

3ES & CHO-KAI CHAN—The aphids (Homoptera: Aphididae)

British Columbia 7. A revised host plant catalogue ...............2eeeceeees 24
NE RRL me PS Garant dee oa Vg See chika owe 6 alse s'e ce veces sees

JOURNAL

of the

ENTOMOLOGICAL

SOCIETY of
BRITISH COLUMBIA

Vol. 75 Issued December 31, 1978

ECONOMIC
WILKINSON, BROWN, FINLAYSON, WILLIAMS & MacKENZIE—Furrow
application of insecticide as a method of controlling wireworms
in potato land
TONKS, EVERSON & THEAKER—HEfficacy of insecticides against
geometrid larvae, Opheroptera spp., on southern Vancouver
Island, British Columbia
CRAM—The effect of root weevils (Coleoptera: Curculionidae) on yield
of five strawberry cultivars in British Columbia

GENERAL
VANDERSAR—Emergence of general predator and parasites of the white
pine weevil, Pissodes strobi (Coleoptera: Curculionidae), in
Engelmann spruce
CANNINGS—The distribution of Tanypteryx hageni (Odonata:
Petaluridae) in British Columbia
BELTON—The mosquitoes of Burnaby Lake, British Columbia

DOGANLAR & BEIRNE—Fruit tree leafrollers (Lepidoptera) and
parasites (Hymenoptera) introduced in the Vancouver
district, British Columbia

DOGANLAR & BEIRNE—Natural enemies of budworms, Choristoneura
spp. (Lepidoptera: Tortricidae) on Douglas fir near Yale,
British Columbia, in 1977

BROWN & KULHAVY —Egg dispersion in the larch casebearer,
Coleophora laricella (Lepidoptera: Coleophoridae), in Northern Idaho

BROWN & KULHAVY—Pre-overwintering mortality in the larch
casebearer, Coleophora laricella (Lepidoptera: Coleoptera) on
western larch in Northern Idaho

HEDLIN & RUTH—Examination of Douglas-fir clones for
differences in susceptibility to damage by cone and seed insects

TAMAKI, OLSEN & GUPTA—Laboratory evaluation of Geocoris
bullatus and Nabis alternatus as predators of Lygus

EVERSON—Buprestidae of southern Vancouver Island
TAXONOMIC

HEPPNER—Eutromula pariana (Clerck) (Lepidoptera: Choreutidae), the
correct name of the apple-and-thorn skeletonizer

SPENCE & SCUDDER—Larval taxonomy and distribution of
Gerris pingreenensis and G. incognitus (Hemiptera:
Gerridae) in British Columbia

CHO-KAI CHAN & FORBES—The aphids (Homoptera: Aphididae)
of British Columbia 5. Name changes

FORBES & CHO-KAI CHAN—The aphids (Homoptera: Aphididae)
of British Columbia 6. Further additions

FORBES & CHO-KAI CHAN—The aphids (Homoptera: Aphididae)
of British Columbia 7. A revised host plant catalogue

SCIENTIFIC NOTE

J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DrEc. 31, 1978

Directors of the Entomological Society of
British Columbia for 1978-1979

President
P. BELTON

Simon Fraser University
Burnaby

President-Elect

R. ELLIOTT
University of B.C.
Vancouver

Past President
A. L. TURNBULL

Simon Fraser University
Burnaby

Secretary-Treasurer

B. D. FRAZER
6660 N.W. Marine Drive,
Vancouver, B.C. V6T 1X2

Editorial Committee
H. R. MacCARTHY

Vancouver

J. CORNER

Vernon

Directors

A.R. FORBES (2nd) D.GILLESPIE (2nd) R. ELLIOTT (2nd)
J. McLEAN (ist) D. CMIROLOVA (ist)

Regional Director of National Society

J. ARRAND
B.C. Min. of Agriculture, Victoria

J. ENTOMOL. Soc. Brit. COLUMBIA 75 (1978), DEc. 31, 1978 3

FURROW APPLICATION OF INSECTICIDE AS A METHOD OF
CONTROLLING WIREWORMS IN POTATO LAND

A. T. S. WILKINSON, M. J. BROWN, D. G. FINLAYSON,
I. H. WILLIAMS AND J. R. MACKENZIE

Research Branch, Agriculture Canada
6660 N.W. Marine Drive, Vancouver, B.C.

ABSTRACT

Three methods of applying insecticides for the control of the wireworm,
Agriotes obscurus L., were tested using fonofos and terbufos. Most treat-
ments gave significantly more marketable tubers than the control. The
furrow treatment gave more consistent results than broadcast or side-dress
and, at 1.1 or 2.2 kg a.i./ha, gave control equal to, or better than, the broad-
cast treatment at 5.6 kg a.i./ha. Analyses by gas chromatography using a
flame photometric detector for residues in potatoes grown in treated soil
showed residues to be less than 0.02 ppm.

INTRODUCTION

Fonofos is one of the most widely and used
insecticides for wireworm control in potatoes.
It is usually applied as granules, broadcast at
5 to 6 kg a.i./ha and mixed into the soil by
discing and rototilling before planting. Broad-
cast treatments are expensive because of the
extra cultivation to apply and mix the insecti-
cide into the soil, and the expense increases
with increasing rates of application. This high
cost is acceptable only if control is good. Effi-
cacy varies, however, even at a high rate of
application, especially in heavy infestations of
wireworms (Wilkinson et al. 1977). Costs are
lower with either side-dressings or furrow treat-
ments because the insecticide can be applied at
planting time. Side-dress has been tested more
often than furrow treatments.

The effectiveness of side-dress treatments
also varies. Onsager et al. (1975) found side-
dressings of fonofos nearly as effective as
broadcast treatments. Carpenter and Scott
(1974) found no significant difference between
fonofos broadcast at 4.5 kg a.i./ha and post-
planting side-dress at 7.8 kg a.i./ha to control
the wireworm Limonius californicus (Mann.).
in 3 experiments, Scott and Carpenter (1976)
testing methods of application to control L.
californicus found no significant difference
between fonofos broadcast at 4.5 kg a.i./ha
and side-dressed at 7.1 kg a.i./ha. In one of
these tests there was no significant difference
between side-dress treatments at 7.1 and 2.7
kg a.i./ha. Toba et al. (1976) found that both
terbufos and fonofos, side-dressed at about
2.2 kg a.i./ha, gave significantly better control
of a light infestation of L. californicus than
when broadcast at 4.0 kg a.i./ha. However,
Toba et al. (1977) found that a broadcast treat-
ment at 6.7 kg a.i./ha gave significantly better
control than a side-dress treatment at 2.2 kg
a.i./ha.

The furrow treatment has not been tested
extensively. Lilly (1973) found fonofos at 2.2
kg a.i./ha gave good control of L. californicus
and was as effective as the broadcast treatment
at 5.6 kg a.i./ha. Scott and Carpenter (1976)
found the furrow method at 7.1 kg a.i./ha gave
significantly better control than the broadcast
treatment of 4.5 kg a.i./ha in one experiment
but in another found no significant difference.

The two experiments reported here were
designed primarily to test the furrow method of
application to control wireworms and to com-
pare it with the broadcast and _ side-dress
methods.

MATERIALS AND METHODS

The experiments were conducted in silt in-
fested with A. obscurus L. Fonofos and ter-
bufos were tested by 3 methods of application
at several rates (Tables 1, 2). Potatoes grown
in 1976 at the site of the first experiment were
severely damaged despite a broadcast treat-
ment of fonofos at about 5.6 kg a.i./ha made
by the farmer. Both fonofos and terbufos were
tested at this site in 1977. The site of the 2nd
experiment had been in sod for several years
and here only fonofos was tested. The experi-
mental plots were 8 x 2 m. In the broadcast
treatment the insecticide was spread evenly
over the soil surface then rototilled to a depth
of 10 cm. Side-dressings were applied in furrows
made on each side of the row and the insecticide
was placed 7 cm from the centre, 2.5 cm below
the level of the seed. In the furrow treatments,
the insecticide was applied with the seed. Each
treatment was replicated 4 times. Potatoes,
cv. Netted Gem, were planted the same day the
treatments were made.

At harvest, 50 tubers from each plot were
examined for wireworm damage and the num-
ber of feeding holes in each tuber was recorded.
Statistical significance of the data was deter-

4 J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DEc. 31, 1978

TABLE 2. A comparison of 3 methods of applying fonofos to control A. obscurus
in soil recently in sod, Cloverdale, B.C. 1977

Rate Reduction of
Method of a.i. Marketable unmarketable
Insecticide Application kg/ha tubers % tubers %
Fonofos 10 G Broadcast 5.6 93.5 a! 80.9
Fonofos 10 G Furrow 1.1 93.0a 79.4
Fonofos 10 G Furrow Dee, 92.0a 76.5
Fonofos 10 G Side-dress 22 87.0a 61.8
Check — _— 66.0 b —

‘Means followed by the same letter are not significantly different at the 5% level of probability.

mined by analysis of variance and Duncan’s
multiple range tests (Duncan 1955).

To detect residues of fonofos and fonofos
oxygen analogue shredded potato was extract-
ed first with acetone then with ethyl acetate.
The solvent was evaporated leaving water
which had been co-extracted from the potato.
This was re-extracted with ethyl acetate.
Following solvent reduction, clean-up was by
column chromatography on a mixed bed of
alumina, silica gel, Florisil and charcoal. Analy-
sis was by gas chromatography using a flame
photometric detector (P mode). To detect

terbufos and its oxygen analogue sulfone,
potato tissue was extracted by acetone followed
by 2 extractions with ethyl acetate. Acetone
was removed by partitioning into a large
volume of water and the remaining ethyl
acetate was concentrated to a suitable volume.
A sample aliquot was cleaned up by column
chromatography on Florisil, silica gel, alumina
and charcoal. Analysis was by gas chromato-
graphy using a flame photometric detector
(P mode). A more detailed description of these
analytical procedures will be published later.

TABLE 3. Insecticide residues found in potatoes grown in soil treated by 3 methods of application

Fonofos 10 G

Terbufos 15G

Method Rate Fonofos Oxygen Terbufos Oxygen
a.i. analogue analogue
kg/ha sulfone
PPM PPM PPM PPM
Experiment 1
Furrow Peal .002! ND? te ND
Furrow 22 O17 ND ND ND
Broadcast 5.6 .004 ND ND ND
Side-dress 22 ND ND ND ND
Check — ND ND ND ND
Experiment 2
Furrow Lt .001 ND
Furrow 2.2 .004 ND
Broadcast 5.6 .004 ND
Side-dress Bed .002 ND
Check = ND ND

'Values given are averages of two analyses
*N D=none detected
°T=trace

RESULTS AND DISCUSSION

In the first experiment (Table 1) all treat-
ments except tuberfos granules side-dressed at
2.2 kg a.i./ha gave significantly more market-
able tubers than the control. The furrow treat-
ments gave the best control with no significant
difference between fonofos and terbufos nor
between the 1.1 and 2.2 kg a.i./ha rates. Ter-
bufos broadcast at 5.6 kg a.i./ha was as effect-
ive as the furrow treatments but fonofos at 5.6
kg a.i./ha gave significantly fewer marketable
tubers. Terbufos side-dressed at 2.2 kg a.i./ha

was significantly more effective than fonofos
side-dressed at the same rate.

In the second experiment (Table 2) only
fonofos was tested. Again, all treatments were
significantly better than the check, with no
significant difference between treatments.

Our results show that the furrow, side-dress,
or broadcast treatments were equally effective.
The efficiency of the lower rates tested sug-
gests that the rate of 7.1 kg a.i./ha, tested by
Scott and Carpenter (1976), and possibly 2.24
kg a.i./ha tested by Lilly (1973), were unneces-

—EEeEeEeEeEeEeEeEeEeEeEeEeEeEeEeEeeeeew

J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DEc. 31, 1978 +)

TABLE 1. Relative effectiveness of 2 insecticides applied by 3 methods for
controlling A. obscurus, Cloverdale, B.C. 1977

Rate Reduction of
Method of acl Marketable unmarketable
Insecticide Application kg/ha tubers % tubers %
Terbufos 15 G Furrow 22 93.0 a! 84.8
Fonofos 10 G Furrow eit 90.0 ab 78.3
Fonofos 10 G Furrow Phe 89.5 ab Nee
Terbufos 15 G Furrow let 89.5 ab tie
Terbufos 15 G Broadcast 5.6 86.5 ab 70.6
Terbufos 15 G Side-dress Zee 79.5 be 55.4
Fonofos 10 G Broadcast 5.6 qOvocd 35.9
Fonofos 10 G Side-dress Pe) 60.5 de 14.1
Check — = 54.0e ad

‘Means followed by the same letter are not significantly different at the 5% level of probability.

sarily high. However, different soil types and
different species of wireworms may require
heavier rates and each should therefore be
tested to determine the optimum rates. On-
sager (1969) reported symptoms of phytotoxi-
city in foliage and a reduction in yield when
potatoes were side-dressed with fonofos at 2.1
kg a.i./ha after the foliage appeared. We ob-
served no phytotoxicity.

Lilly (1973), and Scott and Carpenter (1976)
did not give residue data for fonofos granules.
The results of our residue analyses (Table 3)
show that even at 2.2 kg a.i./ha, fonofos resi-
dues were negligible in tubers harvested 128
days after treatment and the fonofos oxygen
analogue was not detected. Results were similar
with terbufos. Although furrow treatment at

2.2 kg a.i./ha gives a concentration of about
15 times greater than broadcast treatment at
5.6 a.i./ha fonofos, residues in tubers from
furrow-treated plots were 0.02 ppm or less, only
slightly more than from the other treatments.
No residues were found in potatoes from the
control plots in the field that had been broad-
cast-treated with fonofos in 1976. Most of the
insecticides would break down in a year but any
residue would be diluted further by ploughing
to a depth of 20 cm.

Either insecticide at 1.1 kg a.i./ha in the
furrow gave control equal to that of broadcast
at 5.6 kg a.i/ha at about 20% of the cost.
Furthermore, furrow treatment eliminates the
extra expense of spreading and incorporating
the insecticide in the soil.

REFERENCES
Carpenter, G. P., and D. R. Scott. 1974. Sugar beet wireworm control in potatoes in Idaho. J.

Econ. Entomol. 65: 773-5.

Duncan, D. B. 1955. Multiple range and multiple F. tests. Biometrics 11: 1-42.
Lilly, C. E. 1973. Wireworms: efficacy of various insecticides for protection of potatoes in southern

Alberta. J. Econ. Entomol. 66: 1205-7.

Onsager, J. A. 1969. Nonpersistent insecticides for control of Pacific Coast wireworm. Ibid.

62: 1065-7.

Onsager, J. A., B. J. Landis, and L. Fox. 1975. Efficacy of fonofos band treatments and a sampling
plan for estimating wireworm populations on potatoes. Ibid. 68: 199-202.

Scott, D. R., and G. P. Carpenter. 1976. Placement of fonofos for wireworm control on potatoes

in Idaho. Ibid. 69: 444-6.

Toba, H. H., B. J. Landis, and L. L. Foiles. 1976. Potato L. californicus control, Ellensburg,
Washington 1972: (Veg. 83). Insecticide and Acaracide Tests 1: 66.

Toba, H. H., J. E. Turner, D. M. Powell, and W. T. Mander. 1977. Potato wireworm control, Pasco,

Washington, 1975: (Veg. 82). Ibid 2: 67.

Wilkinson, A. T. S., D. G. Finlayson and C. J. Campbell. 1977. Soil incorporation of insecticides
for control of wireworms in potato land in British Columbia. J. Econ. Entomol. 70: 755-8.

6 J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DEc. 31, 1978

EFFICACY OF INSECTICIDES AGAINST
GEOMETRID LARVAE, OPEROPHTERA SPP., ON
SOUTHERN VANCOUVER ISLAND, BRITISH COLUMBIA!

N. V. TONKS, P. R. EVERSON? AND T. L. THEAKER

Saanichton Research Station, Agriculture Canada,
Sidney, British Columbia V8L 1H3

ABSTRACT

Permethrin, acephate, diazinon, malathion, endosulfan, methoxychlor,
Imidan, naled and a spray containing surfactant only were the most effect-
ive treatments for control of winter moth, Operophtera brumata (L.), and
Bruce spanworm, O. bruceata (Hulst), on apple in the tight cluster bud
stage. Resmethrin, trichlorfon, and Dipel and Thuricide formulations of
Bacillus thuringiensis were less effective. The growth disruptor, Dimilin,
provided good control at the pink bud stage. At this same stage, sprays
with surfactant only were no better than untreated controls.

INTRODUCTION

Outbreak populations of hardwood-defoliat-
ing geometrid larvae on southern Vancouver
Island in 1976 were composed of about 10%
Bruce spanworm, Operophtera bruceata (Hulst)
and 90% winter moth, O. brumata (L.) (Gil-
lespie et al 1978). Both species are very similar
in appearance, habits and hosts. The Bruce
spanworm is a North American species which
occurs across southern Canada and the north-
ern U.S.A. The winter moth is a European
insect which became established in Nova Scotia
(Cuming 1961). The Vancouver Island outbreak
is the first record of winter moth from western
North America.

Both moths feed on various ornamental,
shade and fruit trees. DDT, lead arsenate and
azinphosmethyl controlled winter moth in Nova
Scotia (Sanford and Herbert 1966). Azinphos-
methyl, diazinon and endosulfan controlled
Bruce spanworm on apples in the Okanagan
Valley, British Columbia (McMullen 1973).
Dimilin, an insect growth disruptor, has also
shown promise as a winter moth control (Pree
1976). This paper examines the efficacy of 13
insecticides for control of geometrids involved
in the current outbreak on Vancouver Island.
Examination of larval characteristics (Eidt
and Embree 1968) indicate that these are
mostly winter moth, with a small population of
Bruce spanworm.

‘Contribution No. 238, Saanichton Research Station, Agri-
culture Canada, Sidney, B.C.

*Present address: Department of Biology, University of
Victoria, Victoria, B.C.

CONTROL EXPERIMENTS

Treatments listed in Table 1 were applied to
dwarf apple trees (variety unknown) in the
tight cluster bud stage in a neglected orchard
on the campus of the University of Victoria.
Resmethrin was applied with a battery-operat-
ed Turbair ULV applicator. All other materials
were applied to the point of run-off with a hand-
operated Solo Sprayer Model 425. Surfactant
Triton B 1956 was added to all sprays at 30
ml per 100 litres. The experimental plot con-
sisted of 57 trees in randomized complete
blocks containing 19 treatments per block.
There were 3 single-tree replicates per treat-
ment. Living larvae were counted on 10 leaf
clusters selected at random from each tree 8
and 14 days after treatment. Counts from these
2 samples were combined to give 20 samples
per tree for statistical analysis.

In a second experiment 3 rates of Dimilin
25% W.P. were applied at the pink bud stage
in the same manner as above, but no surfactant
was used. These treatments are listed in Table
2. The experimental plot in this trial consisted
of 12 trees in randomized complete blocks
containing 4 treatments per block, with 3
single-tree replicates per treatment. Living
larvae were counted on 10 leaf clusters selected
at random from each tree 9 days after treat-
ment.

In a third experiment, methoxychlor, naled
and Permethrin sprays with and without sur-
factant were applied in the pink bud stage.
This trial also included an untreated control
and a control spray containing surfactant only.
Treatments were not replicated. Living larvae

| J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DEc. 31, 1978 7

Table 1. Number of living Operophtera larvae per leaf cluster on apple

treated with various materials at the tight cluster bud stage.
Treatment Rate of Larvae per
formulation 1.2

a a De Ue Cluster. = ee
Permethrin 50% E.C. 19 ml OF 20a
Permethrin 50% E.C. 37 ml 0.92 db
Acephate 75% S.P. 68 g 0.78 ab
Endosulfan 4 E.C. 124 ml 0.92 abc
Surfactant spray only 30 ml Te1Ocabe
Diazinon 50% E.C. 124 mi 1.17 abc
Malathion 50% E.C. 249 ml 1.47 abcd
Methoxychlor 25% E.C. 498 ml 12.55) abcd
Imidan 50% W.P. 100 g 1.60 abcd
Imidan 50% W.P. 200 g 1.60 abcd
Naled 9.6: E.C. 124 ml 1.88 abcd
Acephate 75% S.P. 131 g 2.05 abcde
Thuricide HPC (Bacillus thuringiensis) 498 ml 2.38 bcde
Trichiorfon 50% $.P. 299 g 2.88 cdef
Thuricide HPC 996 ml 3.ce Cder
Dipel W.P. (Bacillus thuringiensis) 124 g 3.92 ef
Dipel W.P. 248 g 4.20 ef
Resmethrin 0.84% a.i. per litre - 4.2/7 f
Control (untreated) = 8.40 g

Mean of 3 replicates.

2 Values followed by the same letter are not significantly different at

p = .05 (Duncan 1955).

were counted on 10 leaf clusters selected at can’s Multiple Range test (Duncan 1955; Zar

random from each tree 5 days after treatment. 1974). Data from treatments in the third experi-
Data from the first two experiments were ment were analyzed by a two-way analysis

analyzed using a nested analysis of variance. of variance with replication.

Treatment means were compared using Dun-

8 J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DEc. 31, 1978
Table 2. Number of living Operophtera larvae per leaf cluster on apple
treated with Dimilin at the pink bud stage.
Treatment Rate of formulation Larvae per
per 100. litres cluster Une
Dimilin 25% W.P. 25 °q O27 5a
‘ "se 60 g 0.50 a
: et 100 g O.3308
Control - 3.00: b

Mean of 3 replicates.
Yd

p = .05 (Duncan 1955).

RESULTS AND DISCUSSION

In the first experiment, larval infestations
were reduced by all treatments compared to the
untreated control (Table 1). Permethrin,
acephate, endosulfan, diazinon, malathion,
methoxychlor, Imidan, naled and sprays con-
taining surfactant only were most effective.
Resmethrin, trichlorfon and the Dipel and
Thuricide formulations of B. thuringiensis
were less effective.

Values followed by the same letter are not significantly different at

In this experiment, unsprayed trees and
those sprayed with B. thuringiensis, trichlorfon
and Resmethrin were completely defoliated
within 48 days after the tight cluster bud stage.
Trees sprayed with Permethrin were un-
damaged. Most of the remaining materials may
have provided better protection from partial

defoliation if a second spray had been applied,

in the pink bud stage.
In the second experiment, Dimilin reduced

Table 3. Number of living Operophtera larvae per leaf cluster on apple
treated with various materials at the pink bud stage.
Treatment Rate of formulation Larvae per
per 100 litres cluster

Methoxychlor 25% E.C. 498 ml One
Methoxychlor 25% E.C. 498 ml

+ surfactant 30 ml 0.5
Naled 9.6 E.C. 124 ml Onl
Naled 9.6 E.C. 124 mi

+ surfactant 30 ml 0
Permethrin 50% E.C. 19 ml 0
Permethrin 50% E.C. 19 ml

+ surfactant 30 ml 0

J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DEc. 31, 1978 9

larval infestations significantly 9 days after
treatment in the pink bud stage (Table 2).
There were no differences in control among the
3 dosage rates tested.

In the first experiment we obtained excel-
lent control with sprays containing surfactant
only. For this reason we suspected an inter-
action between surfactant and _ insecticides
in the remaining treatments in that trial. How-
ever, the results of the third trial using sprays
with and without surfactant showed no inter-
action (Table 3). There was also no significance
between larval counts from the untreated con-
trol and those from trees sprayed with sur-
factant only.

The variable results obtained with surfac-
tant sprays may be due to a difference in larval

age groups between the first trial and the third
trial. In the first trial there was a higher pro-
portion of early-instar larvae which might
have been more sensitive to surfactant sprays.
However, the relatively light defoliation of
trees treated with surfactant only in the first
trial is unexplained. Further studies are there-
fore required to reach any valid conclusions on
the efficacy of surfactant sprays for control
of winter moth and Bruce spanworm.

ACKNOWLEDGEMENTS
We wish to thank the University of Victoria
for providing the experimental site for these
trials, and J. C. Arrand, B.C. Ministry of
Agriculture, for his advice and assistance.

REFERENCES
Cuming, F. G. 1961. The distribution, life history and economic importance of the winter moth, .
Operophtera brumata (L.) (Lepidoptera: Geometridae), in Nova Scotia. Can. Ent. 93: 135-

142.

Eidt, D. C. and D. G. Embree. 1968. Distinguishing larvae and pupae of the winter moth, Operoph-
tera brumata, and the Bruce spanworm, O. bruceata (Lepidoptera: Geometridae). Can. Ent.

100: 536-539.

Gillespie, David R., Thelma Finlayson, Norman V. Tonks and Douglas A. Ross. 1978. Occurrence
of the winter moth, Operophtera brumata (Lepidoptera: Geometridae), on southern Van-
couver Island, British Columbia. Can. Ent. 110: 223-224.

McMullen, R. D. 1973. The occurrence and control of the Bruce spanworm in the Okanagan Valley,

1972. J. Ent. Soc. B.C. 70: 8-10.

Pree, D. J. 1976. Effects of two insect growth disruptors, PH 6038 and PH 6040, on the winter
moth, Operophtera brumata (Lepidoptera: Geometridae). Can. Ent. 108: 49-52.

Sanford, K. H. and H. J. Herbert. 1966. The influence of spray programs on the fauna of apple
orchards in Nova Scotia. XX. Chemical controls for winter moth, Operophtera brumata
(L.), and their effects on phytophagous mite and predator populations. Can. Ent. 98:

991-999.

10

J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DEc. 31, 1978

THE EFFECT OF ROOT WEEVILS

(COLEOPTERA: CURCULIONIDAE) ON YIELD OF FIVE
STRAWBERRY CULTIVARS IN BRITISH COLUMBIA

W. T. CRAM

Research Station, Agriculture Canada
Vancouver, B.C.

ABSTRACT

To determine the effect of root weevils on strawberry yield, 5 straw-

berry cultivars: Totem, Shuksan, Northwest, Cheam and BC-25 were in- <‘

fested in the field with 2 or 8 adults per plant of 1 of 4 species of root
weevils: the black vine weevil, Otiorhynchus sulcatus (F.); the strawberry
root weevil, O. ovatus L.; the obscure strawberry root weevil, Sciopithes
obscurus Horn; and the woods weevil Nemocestes incomptus (Horn). There
were no significant differences in yield between weevil infestations in the
first cropping season. In the second year plants in the plot infested with
8 O. sulcatus per plant produced significantly less fruit than those in all
other infestations. Within this plot Totem and Cheam produced significantly
more fruit than the other cultivars. In the third year most of the other
weevil-infested plots produced significantly less fruit than the uninfested
plot. The plot with 2 N. incomptus per plant was the most severely damaged
in the third season. The cultivars Totem and Cheam were usually the most
tolerant to all weevils. Northwest and BC-25 were the most susceptible to
all weevils. The tolerance of Totem to attack by the main root weevil
species, O. sulcatus, is probably related to the ability of the plant to produce
and regenerate a large supply of roots.

INTRODUCTION

The criteria for selecting parent plants in a
strawberry breeding program include resistance
or tolerance to major pests. In British Colum-
bia several species of root weevils attack straw-
berry plants (Cram and Neilson 1975). This
paper presents the results of a 3-year yield
study of the 5 strawberry cultivars: Totem,
Shuksan, Northwest, Cheam and BC-25 when
they were subjected initially to 0, 2 or 8 adults
per plant of 1 of the 4 species of root weevils:
the black vine weevil, Otiorhynchus sulcatus
(F.); the strawberry root weevil, O. ovatus L.;
the obscure strawberry root weevil, Sciopithes
obscurus Horn; or the woods weevil, Nemo-
cestes incomptus (Horn).

METHODS

Nine strawberry plots were planted in May,
1971, 2 plots for each weevil species and 1 for
no weevils. For each plot, 5 virus-free plants
of each of the 5 cultivars were set out in 5 rows,
50 cm apart within and between rows in a ran-
domized Latin square design. All blossoms
were removed during this period of establish-
ment and all runners were removed as they
appeared.

To confine the flightless adults of root
weevils an effective barrier was devised that
utilized 4 mil black polyethylene plastic (Fig.
1A). A 1-m wide strip of the plastic was draped
over a 6-mm diameter polyline that had been
stretched over and stapled to 15-cm high cedar
stakes. The lower edges were covered with soil
on each side to anchor the plastic. Both sides
of the plastic were then sprayed with poly-
tetrafluorethylene (‘Fluon’ dispersion GP2).
Adults were unable to climb this slippery verti-
cal surface. This barrier was installed im-
mediately after the plants were set out and was
effective for the 37 months of this study.

Adult weevils collected from strawberry
fields, except S. obscurus which were from
rhododendron, were placed within the barriers
at either 2 or 8 per plant as follows: O. sulcatus
on July 30, O. ovatus on August 6, S. obscurus
on August 13 and N. incomptus on September
3, 1971. Periodic observations indicated that
the adults were successfully established. No
herbicides, insecticides, fungicides or fertilizers
were applied.

The total yield of all fruit from each plant
was recorded for each of 3 years.

— ———————— oor

J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DEc. 31, 1978 Ja

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Fig. 1A. Construction of plastic barriers to contain and exclude flightless root weevil adults. B.
Damage to strawberry cultivars during the second picking season when plants were
initially infested with 8 O. sulcatus adults per plant. The plot with no weevils is in the

immediate background.

RESULTS AND DISCUSSION

In the first cropping season the plants grew
luxuriously. There were no significant yield dif-
ferences between plots but there were signif-
icant differences between cultivars. Cheam
significantly outyielded Totem, Northwest
and BC-25, but not Shuksan (Fig. 2). However,
Cheam was highly susceptible to fruit rot and
had 24 percent rot; the other cultivars had
only 10-12 percent rot.

In the second year the effect of O. sulcatus
was evident. Where 8 O. sulcatus per plant had
been added all the plants were smaller than
normal and showed signs typical of weevil lar-
val damage to their roots (Fig. 1B). The yields
from all other infested plots were not signi-
ficantly reduced. In the plot with 8 O. sulcatus
per plant, the yield of the cultivars Totem and
Cheam were not significantly reduced but
BC-25, Northwest and Shuksan were signifi-

J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DEc. 31, 1978

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J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DEc. 31, 1978 13

cantly reduced over plants with no weevils
(Fig. 2). In the same year the effect of 2 N.
incomptus per plant became evident on BC-25,
Northwest and Shuksan. In fact, all cultivars
were more severely damaged by 2 N. incomptus
per plant than by 8. Possibly the larger number
of adults resulted in crowding that induced the
weevils to leave the shelter of the plants and
succumb to attempts at escape from the
barriered plot, whereas, with only 2 per plant
they may have settled under the plants and ovi-
posited normally.

In the third year the trend to lower yields
in plots with initially lower populations of
adults was even more pronounced. The effect of
2 N. incomptus per plant was striking, causing
severe damage on all cultivars. O. ovatus and
S. obscurus at either level did not usually re-
duce yields significantly even by the third
season. There were only 3 cases where yield
of cultivars in infested plots exceeded the yield
in the plot with no weevils (Fig. 2) and there
were several cases where weevil damage sig-
nificantly lowered yields.

The overall yield of Cheam was significantly
higher than for Shuksan or Totem, which were
in turn significantly higher than BC-25 and
Northwest. Since Cheam is very susceptible to
fruit rot, the choice of preferred parentage for
breeding for weevil tolerance is between Totem
or Shuksan. Totem could be judged superior to
Shuksan on the basis of its second crop per-
formance when subjected to a high population
of O. sulcatus which is the most prevalent and
most damaging species in this area. The ability
of Totem to withstand attack may be related
to its ability to produce a prolific root system.

ACKNOWLEDGEMENTS

I thank the following staff of the Vancouver
Research Station: Dr. H. A. Daubeny, plant
breeder, for supplying the strawberry plants,
Drs. John Hall, statistician, and B. D. Frazer,
ecologist, for assisting with the analysis, and
Mrs. Elaine Easson, and Miss Grace Barclay,
summer student assistants, for assisting in the
field work.

REFERENCES
Cram, W. T. and C. L. Neilson. 1975. Recognition and life history of the major insect and mite
pests of berry crops in British Columbia. B.C. Dept. of Agric. publ’n.

Fig. 2. Yields for 3 years from 5 strawberry cultivars grown together in each of 9 barriered plots
infested initially with 0, 2 or 8 adults per plant of 4 different species of root weevils. For
each year the yields from the plot with no weevils are joined. Treatments enclosed by the
same vertical line are not significantly different. In the legends, treatments or cultivars
that have the same letter are not significantly different according to Duncan’s multiple

range test at P=.05.

14 J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), Dec. 31, 1978

EMERGENCE OF PREDATOR AND PARASITES
OF THE WHITE PINE WEEVIL, PISSODES STROBI
(COLEOPTERA: CURCULIONIDAE) FROM ENGELMANN SPRUCE!

T. J. D. VANDERSAR:?

ABSTRACT

Adult insects of 13 species emerged from 153 leaders of Engelmann
spruce attacked by Pissodes strobi at two British Columbia locations. The
most abundant species was the dipteran, Lonchaea corticis, a scavenger and
predator of immature P. strobi. The most important primary parasites
that attack 4th-instar larvae and pupae were the hymenopterans, Dolicho-
mitus terebrans nubilipennis, Bracon pini, Eurytoma pissodis, and Rho-
palicus pulchripennis. Competition for suitable hosts appears greatest
between the two last-named species, since females exhibited agonistic
behaviour when searching for oviposition sites.

INTRODUCTION

Detailed studies have been carried out by
Harman and Kulman (1967 and 1968) of the
insect fauna associated with the successful
attack and brood establishment of the white
pine weevil, Pissodes strobi Peck, in leaders
of eastern white pine, Pinus strobus L. Less
extensive work has been done on infestations
in Engelmann spruce, Picea engelmannii Parry
(Stevenson, 1967). Little is known, however,
of the mechanisms that the parasites might
employ to minimize competition for suitable
white pine weevil hosts and to synchronize
their emergence with the host’s life cycle. My
observations on Engelmann spruce populations
had indicated that most of the parasite species
overwintered in the damaged leaders from
which P. strobi had emerged the previous
autumn. This paper reports the sequence of
emergence of the parasite complex in the
spring, and indicates the temporal partitioning
of the parasite species in their utilization of the
weevil hosts under field conditions.

METHODS AND MATERIALS

One hundred fifty-three dead terminals of
young, open-grown Engelmann spruce attacked
by P. strobi in 1976 were collected on May 6
and 7, 1977. Most of the leaders (132) were
collected from Kootenay National Park, B.C.,
and the remainder from Glacier National Park,
B.C., 640 km northwest of the initial collection
site.

Each leader was put into a polyethylene
bag and maintained in the laboratory at 20-
24°C. The number and species of insects that
emerged from each leader was recorded daily.
Hymenopteran insects were held in small rear-

‘Research supported by National Research Council of
Canada Operating Grant No. A3887.

*Department of Biological Sciences, Simon Fraser Univer-
sity, Burnaby, B.C. V5A 1S6.

ing cages to study inter- and intra-specific
agonistic behaviour, whereas dipterans were
identified and released after examination of
the leaders. The number of emergence holes of
weevils in the periderm of each leader were
counted to assess the field emergence of adults
from these leaders in autumn 1976.

RESULTS AND DISCUSSION

Table 1 shows the numbers and species of
insects that emerged from the 153 leaders in-
cluding species new to Engelmann spruce. The
most abundant insect was a dipteran, Lonchaea
corticis Taylor, a scavenger and predator of
immature P. strobi (Harman and Kulman,
1967), particularly of pupae (R.I. Alfaro, pers.
comm.). Construction of chip cocoons by 4th-
instar weevil larvae in preparation for pupation
may have adaptive significance not only to
prevent desiccation, but also as a physical
deterrent to predation by L. corticis. The
principal parasite species were hymenopterans:
Dolichomitus terebrans nubilipennis Viereck,
Eurytoma_ pissodis Girault, Bracon pini
Muesebeck, and MRhopalicus pulchripennis
Crawford. Harman and Kulman (1967) and
Stevenson (1967) verified that these four
hymenopterans are primary parasites of white
pine weevils infesting eastern white pine and
Engelmann spruce, respectively. Stevenson
(1967) recovered significant numbers of the
braconid, Eubadizon strigitergum Cushman,
and the ichneumonid, Helcostizus rufiscutum
Cushman from Engelmann spruce leaders
attacked by P. strobi in Kootenay National
Park, B.C.; nevertheless, these two primary
parasites were not recovered in the present
study. Stevenson (1967) did not, however,
specify their peak emergence periods.

The status of the remaining insect species
listed in Table 1 is less well known, although
Harman and Kulman (1967) report that
Pseudoeucoila sp. is itself a parasite of L. cor-
ticis. Little is known of the general biology of

15

J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DEc. 31, 1978

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16 J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DEc. 31, 1978

Pilinothrix sp. which has not previously been
reported from conifer terminals attacked by
P. strobi.

Associated insects emerged from 90% of the
spruce leaders collected in Kootenay National
Park, but only 35% of these leaders bore evi-
dence of successful emergence by weevils in
the previous autumn. Comparable data from
Glacier National Park indicated that weevils
had emerged from 38% of the spruce leaders,
whereas associated insects emerged from 67%.
In both locations, the emergence of white pine
weevils from attacked and killed spruce leaders
was low, with a mean of only one adult per
leader based on the count of emergence holes.
These data suggest that entomophagous in-
sects play a pivotal role in regulating the
population of the weevils. Particularly im-
portant is L. corticis because each predator
larva commonly attacks more than one im-
mature weevil to complete its development
(R.I. Alfaro, pers. comm.). The four species of
primary parasites are probably of relatively
minor importance in the regulation of weevil
populations.

Figures 1-5 show the emergence over 28
days of L. corticis and four primary parasites
from the spruce leaders. The median emergence
date for L. corticis was May 16, but the pri-

400

300

200

NUMBER OF INSECTS

100

105 2124-44 16% -18e ~20... 22
MAY

mary parasite species combined had a bimodal
emergence pattern. The median emergence
dates for D. terebrans nubilipennis and B. pini
were May 11 and 12, respectively. Stevenson
(1967) reported that D. t. nubilipennis emerged
in the field during a 4-week period from late
May to June. Although early instar weevil
larvae are present in attacked host leaders in
June, oviposition by D. t. nubilipennis is delay-
ed until July when 4th-instar larvae are avail-
able. Among the four primary parasites, only
D. t. nubilipennis is morphologically adapted
to oviposit alongside deep-lying P. strobi larvae
that have constructed pupation chambers with-
in the pith of the leader (Stevenson, 1967).

The median emergence dates for R. pulchri-
pennis and E. pissodis were May 30 and June 1,
respectively. Of particular interest was the
agonistic behaviour, both inter- and _ intra-
specific, which I observed between these two
similar-sized parasites. In a rearing cage, mated
females of both species were observed attempt-
ing to oviposit into the wooden surfaces al-
though no spruce leaders or white pine weevils
were present. When two females of the same or
different species met on this substrate, one or
both adopted a characteristic threat posture
in which both the abdomen and prothoracic
legs were raised and the wings held over the

@ Lonchaea corticis

DATE OF EMERGENCE FROM LEADERS

Figure 1. Daily emergence of Lonchaea corticis during May 10 - June 6, 1977, from Engelmann
spruce leaders naturally attacked by Pissodes strobi in 1976 at two locations in British

Columbia, 640 km apart.

J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DEc. 31, 1978 17

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Figures 2-5. Daily emergence of 4 species of primary, entomophagous hymenoptera during May
10 - June 6, 1977, from Engelmann spruce leaders naturally attacked by Pissodes strobi
in 1976 at two locations in British Columbia, 640 km apart.

18

abdomen in a V-shape. Rapid butting contests
would sometimes ensue until one or the other
female retreated. More frequently, the threat
posture deterred the advance of an approaching
female, but several intances of butting were
followed by grappling. Beaver (1967) reported
similar agonistic behaviour in pteromalids
competing for food resources or oviposition
sites. R. pulchripennis and E. pissodis also
compete for scolytid hosts such as Dendroc-

J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DEc. 31, 1978

tonus monticolae Hopkins (Bushing, 1965),
Agonistic behaviour between these competing
parasite species is likely to promote dispersal
of the gravid females in the field.

ACKNOWLEDGEMENTS
I thank G. VanderSar, J. Holman, and L.
Chong for assistance with laboratory pro-
cedures, and J. H. Borden for review of the
manuscript.

REFERENCES
Beaver, R. A. 1967. Hymenoptera associated with elm bark beetles in Wytham Wood, Berks.
Trans. Soc. British Entomol. 17: 141-150.

Bushing, R. W. 1965. A synoptic list of the parasites of Scolytidae (Coleoptera) in North America
north of Mexico. Can. Entomol. 97: 449-492.

Harman, D. M., and H. M. Kulman. 1968. Biology and natural control of the white pine weevil in
Virginia. Ann. Entomol. Soc. Amer. 61: 280-285.

Harman, D. M., and H. M. Kulman. 1967. Parasites and predators of the white-pine weevil,
Pissodes strobi (Peck). Univ. Maryland, Nat. Res. Inst. Contrib. 323, 35 pp.

Stevenson, R. E. 1967. Notes on the biology of the Engelmann spruce weevil, Pissodes engelmanm
(Curculionidae: Coleoptera) and its parasites and predators. Can. Entomol. 99: 201-213.

THE DISTRIBUTION OF TANYPTER YX HAGENI
(ODONATA:PETALURIDAE) IN BRITISH COLUMBIA

ROBERT A. CANNINGS

3-725 Vancouver St.,
Victoria, B.C. V8V 3V4

ABSTRACT
In British Columbia the petalurid dragonfly Tanypteryx hageni (Selys)

is considered to be rare. A record in 1977 extends its known range almost
to 51°N latitude. The record also disputes the belief that 7. hageni normally
is restricted to subalpine habitats. In the northern parts of its range it

appears to occur naturally at sea level.

INTRODUCTION

Tanypteryx hageni (Selys) is the only west-
ern North American representative of the
primitive dragonfly family Petaluridae. The
family has a distribution so limited and dis-
junct that the nearest relatives of T. hageni are
T. pryeri Selys in Japan and Tachopteryx
thoreyi (Hagen) in eastern North America.

Tanypteryx hageni ranges from south-
western British Columbia south through the
mountains to California and Nevada (Cannings
and Stuart, 1977). American localities are dis-
cussed in Kennedy (1917), Whitney (1947),
Smith and Pritchard (1956), Svihla (1959) and
Paulson and Garrison (1977). In Washington
and Oregon the larvae are known to inhabit

J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DEc. 31, 1978 19

mountain bogs at high altitudes where they
burrow in wet muck and mosses associated
with springs (Svihla, 1959). Larvae have never
been found in British Columbia.

By 1976, T. hageni had been recorded from
only four localities in British Columbia (Scud-
der et al., 1976): Black Mountain, North Van-
couver (1080 m), 9 Aug. 1931 (H. B. Leech):
Liumchin Creek, Cultus Lake (150 m), 8 Jul
1934 (W. E. Ricker); Hell’s Gate, near Yale
(150 m), 30 Aug 1938 (W. E. Ricker); and
Diamond Head, Garibaldi Park (1000 m), Jul
1969 (R. H. Carcasson).

All these localities are within the Cadcade
Mountains or the extreme southern Coast
Mountains of southwestern British Columbia.
The Black Mountain and Diamond Head locali-
ties are in subalpine forest at 1000 m or higher.
These habitats are similar to those at high
altitudes reported for 7. hageni in the United
States. Occurrences of this insect at lower ele-
vations, such as the Liumchin Creek and Yale
records, always have been considered acci-
dental (Whitehouse, 1941; Walker, 1958).

A recent distribution record for T. hageni
suggests that these low-altitude records are
not exceptional. The location is the mouth of
the Ahnuhati River on Knight Inlet, 50°52’N
latitude, about 250 km northwest of Vancouver
or about 230 km northwest of the previous
most northerly record of the species. Two speci-
mens, a male and a female, were captured on
20 and 21 Jul 1977. Each was salvaged by Mr.
Kevin Lloyd after it had been caught and killed
by a pet housecat. The specimens were deposit-

ed in the Spencer-Entomological Museum,
University of British Columbia.

The dragonflies apparently were attracted
to a muddy area on the beach where water
gently flowed over it from the cliffs above.
Five or six other large black and yellow dragon-
flies were sighted along the banks of the Ahnu-
hati River. Possibly some of these were Cordu-
legaster dorsalis and not T. hageni.

This is an important record because the
dragonflies apparently were residents of the
coastal western hemlock forest at sea level and
not merely strays from the mountains above.
Evidently, in the northern part of its range,
Tanypteryx hageni is not restricted to high
elevations, for of the six specimens from British
Columbia, four were from elevations of 150 m
or lower. As suspected by Ricker (pers. comm.),
at low elevations these dragonflies may develop
in muddy or mossy seepages like those which
larvae are known to inhabit in subalpine en-
vironments to the south. This habitat occurs
along streambanks and in other cool, damp
locations in lowland forests. The species is
probably distributed more extensively to the
north in British Columbia than was previously
recognized and may not be so rare as was once
supposed.

ACKNOWLEDGEMENTS
I thank Mr. Kevin Lloyd for making the
collection at Knight Inlet and for the details
concerning the habitat. Dr. W. E. Ricker
supplied data on his own collections, and Dr.
G. G. Scudder read the manuscript.

REFERENCES

Cannings, R. A. and K. M. Stuart. 1977. The Dragonfliés of British Columbia. B.C. Prov. Mus.
Handbook No. 35, Victoria.

Kennedy, C. H. 1917. Notes on the life history and ecology of the dragonflies (Odonata) of central
California and Nevada. Proc. U.S. Nat. Mus. 52:483-635.

Paulson, D. R. and R. W. Garrison. 1977. A list and new distributional records of Pacific Coast
Odonata. The Pan-Pacific Entomologist 52:147-160.

Scudder, G. G. E., R. A. Cannings and K. M. Stuart. 1976. An annotated checklist of the Odonata
(Insecta) of British Columbia. Syesis 9:143-162.

Smith, R. F. and A. E. Pritchard. 1956. Odonata, pp. 106-153 in R. L. Usinger, ed., Aquatic Insects
of California. Univ. of California Press, Berkeley.

Svihla, A. 1959. Life history of Tanypteryx hageni Selys (Odonata). Trans. Amer. Ent. Soc.
85:219-232.

Walker, E. M. 1958. The Odonata of Canada and Alaska. Vol. 2. Univ. of Toronto Press, Toronto.

Whitehouse, F. C. 1941. British Columbia dragonflies (Odonata) with notes on distribution and
habits. Amer. Midl. Nat. 26:488-557.

Whitney, R. C. 1947. Notes on Tanypteryx hageni. Ent. News 58:103.

20 J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DEc. 31, 1978

THE MOSQUITOES OF BURNABY LAKE
BRITISH COLUMBIA

PETER BELTON

Pestology Centre, Department of Biological Sciences
Simon Fraser University, Burnaby, British Columbia V5A 1S6

ABSTRACT

Ten species were found in a survey of the mosquitoes of the Burnaby
Lake area; they included a small breeding population of Aedes aloponotum,
a species not recorded in British Columbia since 1919. Aedes aboriginis
was more numerous and troublesome. Aedes sierrensis and Mansonia pertur-
bans, which bite both in the open and in houses, were less common, but
because they are unaffected by the usual larval control techniques, are
potential nuisance species in the area. Aedes cinereus and Culiseta morsi-
tans were abundant, but the former bit only when disturbed and the latter

did not bite humans.

INTRODUCTION

Burnaby Lake, near Vancouver, is the
shallow drainage area of a once extensive peat-
filled bog that drains slowly into the Fraser
River. The general public and naturalists make
considerable use of the area which is now a bird
sanctuary. A narrow margin of marsh and
woodland is preserved as a nature park.

The water level of the lake is controlled by
a dam installed in 1923, and until recently the
area was inaccessible, so that the mixed wood-
land and marsh have probably not changed
much since 1921 when Hearle (1926) concluded
a 3-year survey of the mosquitoes of the lower
Fraser valley. However, most of the surround-
ing forested area within flight range of mos-
quitoes is now cleared and developed, leaving
the lake populations isolated.

METHODS

Immature mosquitoes were collected from
breeding sites and adults were sampled from
swarms or as they came to bite. When females
were numerous, standard counts were made of
the number of mosquitoes landing on the front
of the trousers between waist and knees, for
two l-min periods separated by 5 min (Agri-
culture Canada, 1972).

RESULTS

Ten species, representing the five genera
of mosquitoes so far found in British Columbia,
were collected around the lake. The immature
stages that were collected are listed by habitat
in Table I. Their biology is described in more
detail below.

Anopheles punctipennis (Say): - This
species was collected only in the larval stage.
It was not numerous compared with other
species in the same habitat and was never
observed biting or resting under bridges or
culverts where I have usually found it in late
summer in other areas.

Aedes aboriginis Dyar: - This is the most
numerous biting species and the most trouble-
some to humans. Larvae were found as early
as mid-April in clearings and at the margins of
the woodland in pools that ranged from the
size of a horse’s hoofprint to more than 10 m
in diameter. Few adults were seen for about
two weeks after they had emerged from the
pupae. Several swarms of up to 20 males were
seen in late May and early June 3-15 m above
the ground, at the tips of branches on the lee
or north side of broadleaf maples and cotton-
woods. Females bit readily from late afternoon
to at least an hour after sunset, when obser-
vations were discontinued. Females were pre-
sent in clearings in wooded areas and in gar-
dens at least 1 km from the nearest known
breeding site. A landing rate of more than
5/min was measured at sunset in a picnic area
about 400 m from a breeding site.

Aedes aloponotum Dyar: - Four large mos-
quitoes with pale banded tarsi and an orange
brown scutum were taken in the late afternoon
and evening between May 16th and July 12th,

1977. These proved to be the first specimens of.

A. aloponotum recognized in the province
since Hearle’s survey (Hearle, 1926). A sys-
tematic search in May 1978 of potential breed-
ing sites, upwind of the area where the adults
were collected, yielded two pupae associated
with many larvae of A. cinereus in grass-lined
pools 25 m from the main creek that feeds
the lake. These were identified at emergence,
on May 15th, as A. aloponotum. The first
adults biting in 1978 were taken on June 3rd,
in the same area as those found in 1977.

Aedes cinereus Meigen: - This was the most
numerous aedine mosquito encountered. Larvae
were dense in open grassy pools at the margin
of the woodland and the lake and in shallow
pools within the wood in which reedmace and
burr-reed were growing. Apart from one refer-
ence to a cloud of males found in late afternoon

J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), Dec. 31, 1978 21

TABLE 1. Immature mosquitoes found round Burnaby Lake, by habitat.

peat

Lake:

Habitat Species Month Stage

Ditches:

outside woodland, sluggish Ca. incidens April - Oct. E, L, P?

road and railway drainage C. pipiens July - Oct. E,L, P
An. punctipennis June - Aug. L

Woodland pools:

dead leaf bottom A. aboriginis April - May | Weel es
Ca. inornata May - July | ae ed
Ca. morsitans April - Aug. L, P

Pools in open:

dead grass bottom A. aloponotum May Je
A. cinereus April - May L,. P

peat bottom! Ca. morsitans April - July | Wes) ed

Stagnant channels:

connected with lake Ca. morsitans April - Aug. L, P

openings in vegetation Ca. morsitans June - Sept. Ae es

mats fringing lake!

'These sites were sampled in February, the remainder only between April and October.

*Abbreviations: E, eggs; L, larvae; P, pupae.

(Edwards, 1932), swarming does not appear to
have been described in this species. In late May
and early June, I observed one large swarm
in the same region, on several evenings just
after sunset. It consisted of at least 100 males
swarming less than 1 m from the ground over
horsetails. Females flew into the swarm, often
after biting the observer. Mating occurred at a
rate between 5 and 10/min. Females did not
appear to seek human hosts actively but did
not hesitate to bite when disturbed in the after-
noon or evening. Adults were only seen in un-
disturbed flight within about an hour of sunset.

Aedes sierrensis (Ludlow): - Immature
stages and their preferred breeding site, i.e.
water-filled tree holes, were not found. From
about 20 females that bit the observer between
June and September, three were caged indi-
vidually and laid fertile eggs. One male was
collected an hour before sunset hovering
around the observer, confirming several pre-
vious observations that males are attracted to
hosts and mate with females as they fly in to
bite (Curtis, 1957). During the summer, several
females were found biting in the house.

Culex pipiens L.: - Larvae and pupae were
found in the open in stagnant drainage ditches,
flooded vehicle tracks and artificial containers.
Swarms of about ten males were found on
several evenings over Douglas spirea bushes
at the margin of the lake, from mid June to
July. Later in the season this species swarms
over the south walls of houses and buildings.
No mating was seen in any of the swarms and
no females were seen to bite outdoors. Females

of this species enter houses in late August and
September and a high proportion appear to
take blood meals during the night.

Culiseta incidens (Thomson): - Egg rafts,
larvae and pupae were found over a wide area
in drainage ditches and in some artificial con-
tainers. Adult females were occasionally found
under the eaves of houses and garages during
the summer and autumn but these did not
bite when placed in a tube over the observer’s
arm. No adult males of this species were found.

Culiseta inornata (Williston): - Larvae and
pupae breed in deep pools in shaded woodland.
Adults that appeared to be freshly emerged
were found resting on moss beside one such
pool in May. On two occasions a pair was in
copula. Females occasionally bit in the wood-
land but were more numerous and appeared to
be more aggressive near the lake.

Culiseta morsitans (Theobald): - This is the
most abundant mosquito. Larvae were found in
almost every still pool with brown peaty water
including pools in floating mats of vegetation
at the edge of the lake. No larvae were found
in known breeding areas before March, al-
though they overwinter in this stage in Europe
(Marshall 1938). Several breeding sites were
frozen solid in early January 1978, and the
deeper pools were covered with 10 - 20 cm of
ice. Despite the abundance of immature stages,
only one swarm of males was seen at sunset in
late June. About 10 males flew in an extended
figure-of-eight about 1 m in a north-south
direction among the leaves and branches of a
cascara tree 2 m above the ground. Only two

99 J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DEc. 31, 1978

females were taken in flight at the margin of
the lake. Neither they nor any reared females
could be persuaded to take human blood.

Mansonia perturbans (Walker): - Females
bit in the woodland from mid-June to August
in the afternoon and evening. Although several
dozen clumps of reedmace were uprooted, wash-
ed and examined, no immature stages were
found. From late June to September, females
bit in the evening inside a house 1 km from the
lake. No males were seen.

DISCUSSION & CONCLUSIONS

The most significant finding is the redis-
covery of A. aloponotum. Wood (1977) describ-
ed how this species was lost in synonymy for
some 30 years and points out that Canadian
material in the National collection consists of
“a few females . .. from the lower Fraser
Valley, most in poor condition”’, none of which
was collected since the 1920’s. Wood identified
two of the females captured while biting in 1977
as aloponotum and this prompted a systematic
search for its breeding site in 1978. The pupae
were collected on May 13th, in a pool about
400 m from where the adults were caught.

The earliest that any female Aedes bit was
about 2 weeks after the majority had emerged
from the breeding sites I sampled. During this
period, however, two female aboriginis were
observed on flowers of wild crabapple. This
supports the observations of Service (1972)
and others, that in several species, both sexes
feed on nectar for a few weeks before the
females disperse for blood meals.

Hearle commented (1926) that ‘‘during three
years ... very few specimens (of C. pipiens)
have been collected. It would appear that this
species has been introduced comparatively
recently’. In the 1970’s I have found C. pipiens
as numerous as Ca. incidens which it appears
to be displacing in artificial and temporary
breeding sites.

My observations on the biting habits of
A. aboriginis and sierrensis also differ from
Hearle’s. He considered that the former was
“neither very vicious nor persistent’ and that
the latter ‘are timid in approaching human
beings”. Around Burnaby Lake both species
are now bold and persistent in their attacks on
man and one wonders if their behaviour may
have changed after 50 years of exposure to this
relatively new and abundant host.

Of 21 species that Hearle (1926) collected in
numbers in the valley, 13 would be expected to
occur in the habitats around Burnaby Lake;
of these 13, at least nine are still present. It
appears that the isolation of the lake has had
little effect on the number of species. Culiseta
morsitans is the only species that Hearle did
not collect, and it is surprising that it was
sO numerous at what appears to be the south-
ern limit of its range (Curtis 1967).

Only A. aboriginis appears to be a nuisance
around Burnaby Lake, occasionally invading a
nearby picnic site with a landing rate of more
than 5/min. Repellents seem to be an adequate
solution for the public as they are for the
naturalists walking the trails in the evening.
A. sierrensis and M. perturbans could be a
problem to homeowners in warm and wet
summers because both species readily enter
houses. Neither is affected by normal larval
control procedures and insect screens may be
the only effective solution.

ACKNOWLEDGEMENTS

I thank Dr. D. M. Wood of the Canada
Agriculture Biosystematics Research Institute,
Ottawa, for identifying A. aloponotum and for
his encouragement in my search for its
immature stages. Thanks are also due to
several members of my family who acted as
attractants for female mosquitoes. The survey
was made during a Sabbatical leave from Simon
Fraser University.

REFERENCES
Agriculture Canada, 1972. Planning an anti-mosquito campaign. Pub. No. 1485, 15 pp.

Curtis, L. C. 1967. The mosquitoes of British Columbia. Occasional Papers, B.C. Provincial

Museum, No. 15, 90 pp.

Edwards, F. W. 1932. Anopheles algeriensis, Theobald (Diptera, Culcidae) in N Norfolk. J. Ent.

Soc. S. Eng. 1: 26.

Hearle, E. 1926. The mosquitoes of the lower Fraser Valley, British Columbia, and their control.
National Research Council of Canada Report No. 17, 94 pp.

Marshall, J. F. 1938. The British Mosquitoes. British Museum, London, 341 pp.

Service, M. W. 1972. Flight activities of mosquitoes with emphasis on host seeking behaviour.
In: Symposium on biting fly control and environmental quality. Ed. A. Hudson: 125-132.
Defence Research Board of Canada Pub. No. DR 217.

Wood, D. M. 1977. Notes on the identities of some common Nearctic Aedes mosquitoes. Mosq.

News 37: 71-81.

J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DEc. 31, 1978 23

FRUIT TREE LEAFROLLERS (LEPIDOPTERA) AND
PARASITES (HYMENOPTERA) INTRODUCED IN THE
VANCOUVER DISTRICT, BRITISH COLUMBIA

MIKTAT DOGANLAR AND BRYAN P. BEIRNE!

ABSTRACT
Introduced European species comprised 5 of the 6 most common and 8
of the 11 total species of leafrollers found on apple and pear in the Van-
couver district in 1977. Parasitism was low. Two of the leafroller parasites,
Apanteles ater (Ratz.) and A. longicauda (Wesm.), and a gracilariid para-
site, Achrysocharoides zwolferi (Delucchi), are European species new to

North America.

LEAFROLLERS

One, Choristoneura rosaceana (Harr.), of the
six most common species of leafrollers found on
apple and pear in the Vancouver district in 1977
is native to North America. The other five were
introduced to North America from Europe.
They are: Croesia holmiana (L.), found in North
America for the first time in this survey and
recorded elsewhere (Doganlar and Beirne,
in preparation); and Hedia nubiferana (Haw.),
Spilonota ocellana (Den. and Schiff.), Pandemis
cerasana Hbn., and Archips rosanus (L.), all
already known to inhabit the district.

Other species of leafrollers found on apple
and pear were: Acleris comariana (Zell.), pre-
viously recorded only as a strawberry pest in
B.C. Archips podana (Scop.), and Acleris
variegana (Schiff.), all introduced species;
Pandemis canadana Kft., a native species; and
Acleris robinsoniana (Forbes), whose status as
a Holarctic or Nearactic species appears to be
obscure. These species were found in only small
numbers.

Eight of the 11 species of leafrollers men-
tioned above are non-natives that were intro-
duced accidentally into North America, 5 of
them apparently first into southwestern British
Columbia or the Pacific Northwest. Only one
of the introduced species, A. rosanus, has so
far spread into the Okanagan Valley, where it
was first found in 1971 as an apple pest in 1972.
Others of the introduced species may become
important pests when they colonize the Okana-
gan Valley or the fruit growing regions of the
interior of Washington and Oregon, as their
distributions abroad indicate that they could
survive the climate there, at least in irrigated
situations.

PARASITES
Two of the three species of hymenopterous
parasites that were reared from two or more
of the six most common species of leafrollers
(none was reared from the other five) are
apparently accidentally-introduced European

'Pestology Centre, Department of Biological Sciences, Simon
Fraser University, Burnaby, B.C., V5A 1S6.

species. They are: Apanteles ater (Ratz.),
reared from P. cerasana, A. rosanus, C. rosa-
ceana, and H. nubiferana and not recorded pre-
viously from North America; and Apanteles
longicauda (Wesm.), reared from H. nufiberana
and C. rosaceana and also not recorded pre-
viously from North America.

Ascogaster quadridentata Wesm., reared
from S. ocellana, was deliberately introduced
from England into the Lower Fraser Valley in
the 1940’s as a biological control agent of the
pea moth, Laspeyresia nigricana (Steph.),
itself an accidentally introduced species. The
morphologically identical form known as
A. carposapsae Vier was introduced into B.C.
from Ontario in the 1930’s as a biological con-
trol agent of the codling moth, L. pomonella
(L.), and became established. It is not yet
known which of these forms is the parasite of
S. ocellana.

Spilonota ocellana was also parasitized by
Agathis dimidiator (Nees), a European species
probably accidentally introduced into Eastern
North America and apparently not recorded
previously from the West.

The European eulophid Achrysocharoides
zwolferi (Delucchi) was reared from the graci-
lariid Phyllonorycter blancardella Forb. during
this survey. It also has not been recorded pre-
viously from North America. At Burnaby,
British Columbia it has three generations a
year, Overwinters as a pupa inside the larval
web of its host, and was reared from nearly 10
percent of the host larvae collected.

Other parasites reared from the leafrollers
were: Meteorus argyotaeniae Joh., from H.
nubiferana, C. rosaceana, and S. ocellana;
Enytus sp. (or spp.), from C. holmiana and
H. nubiferana; Tranosema sp. (or spp.), from
C. rosaceana and C. holmiana; and Macrocen-
trus iridescens French, Scambus (S.) decorus
Walley, Ischnus inquisitorius atriceps (Cress.),
Apanteles sp., and Miscogaster sp., from
C. rosaceana.

The native species of leafroller, C. rosaceana,
had 9 species of parasites and a total para-
sitism of under 10 percent. The five introduced

24 J. ENTOMOL. SOc. BRIT. COLUMBIA 75 (1978), DEc. 31, 1978

of the six most common species had one to four
species each. Total parasitism averaged 5 per-
cent and ranged from less than 1 percent in
C. holmiana to about 8 percent in H. nubi-
ferana.

None of the parasites identified in this sur-
vey was the same as any of those identified
from a survey of parasites of apple leafrollers
on various foodplants in the Okanagan Valley,
B.C., in 1972 (Mayer and Bierne, 1974. J. ent.
Soc. B.C. 71: 22-25).

“While this paper was in press Phyllonorycter blaucardella
Forb. was found to be a different and undescribed species.”’

ACKNOWLEDGEMENTS

The authors thank Dr. A. Mutuura and Dr.
W.R. M. Mason, Dr. C. M. Yoshimoto, and Mr.
H. E. Bisdee, all of the Biosystematics Re-
search Institute, Canada Agriculture, Ottawa
for identifying the Lepidoptera and Hymen-
optera, respectively, and Dr. Elsbeth Belton,
Simon Fraser University, for information on
the nomenclature and distributions of the
leafrollers.

.. AN ERRONEOUS REFERENCE TO
AEDES AEGYPTI (L.) IN BRITISH COLUMBIA

PETER BELTON

Pestology Centre
Department of Biological Sciences
Simon Fraser University
Burnaby, B.C.

There is an unfortunate error in the stand-
ard monograph “‘Aedes aegypti (L.) the yellow
fever mosquito” by Sir. S. Rickard Christo-
phers (1960).

In dealing with the northern limits of its
distribution, Christophers states: ‘There is,
however, a record (Good, 1945) stating that
A. aegypti used to occur in British Columbia,
but has not been recorded for thirty years’’.
This record is included in his Figure 1, a map
showing the world distribution of the species
and in his Table 1, the recorded northern limits
of its distribution. However, British Columbia
is not mentioned in Good’s paper, which is a
list of mosquitoes of the District of Columbia.

The list does include A. aegypti, collected by
J. Carrol on August 3rd 1901.

The present northern limit of A. aegypti
on the west coast is Baja California although
interceptions are occasionally made by quaran-
tine officials in the state of California (Bohart
and Washino 1978).

Summer temperatures in both North and
South America (July & January respectively)
are lower on the west coast than at correspond-
ing latitudes on the east coast. Ignoring the
erroneous British Columbia record, the present
distribution of A. aegypti in the Americas
corresponds closely with the 21 C summer iso-
therm.

REFERENCES
Bohart, R. M. and Washino, R. K. 1978. Mosquitoes of California. 3rd Edition, University of Cali-

fornia, Berkeley.

Christophers, Sir. S. R. 1960. Aédes aegypti (L.) the yellow fever mosquito: its life history, bio-
nomics and structure. Cambridge Univ. Press.

Good, N. E. 1945. A list of mosquitoes of the District of Columbia. Proc. Entomol. Soc. Wash.

47: 168-197.

J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), Dec. 31, 1978 25

NATURAL ENEMIES OF BUDWORMS,
CHORISTONEURA SPP. (LEPIDOPTERA: TORTRICIDAE),
ON DOUGLAS FIR NEAR YALE, BRITISH COLUMBIA, IN 1977

MIKTAT DOGANLAR' AND BRYAN P. BEIRNE

Pestology Centre, Simon Fraser University,
Burnaby, British Columbia

ABSTRACT

Two species of Choristoneura were reared from an infestation on Douglas
fir in the Yale-Spuzzum area in 1977: occidentalis Free. and an apparently
undescribed species. Larvae with parasites averaged 47.6 percent and in-
creased from 14.5 percent in larvae collected early in May to 74 percent in
those collected early in July. Pupae with parasitism were 52 percent. Three
well-known species of budworm parasites comprised 85 percent of the
parasites reared. Eight other species of Lepidoptera were reared from the
Douglas fir. One of these, Dioryctria pseudotsugella Munroe, becomes a
predator on budworm prepupae and pupae when all the foodplant foliage

has been consumed by budworms.

INTRODUCTION
The controversial decision, subsequently
revoked, to spray the infestation of budworm in
the Fraser Canyon district with chemical pesti-
cides in 1977 was made apparently without
adequate evaluation of the importance of
parasites and predators that might contribute
to the collapse of the outbreak but could be
harmed by the pesticides. Surveys were made
in the Yale-Spuzzum area of the Canyon in the
spring and early summer of 1977 to obtain
some indications of the identities and im-

portance of the parasitic insects.

METHODS

Douglas fir was the only kind of tree seen to
be regularly infested heavily; it comprises 0.4
to 68 percent of the trees per acre in that area
(data from G. Williams). About 5,000 budworm
larvae and pupae were obtained. Collections
were made on 7 May, 13 June, and 7 July by
taking infested branches from trees. A total of
15 Douglas fir, 20-50 cm in diameter, were
felled and sampled but some collections were
from small firs of about 5 cm diameter.

Choristoneura larvae were selected at
random from the branches collected on 7 May
and 13 June. Ten groups of 20 from each date
were reared separately, for a total of 400. All
of the 110 larvae and 603 pupae collected on 7
July were reared individually. Parasites that
emerged were sent for identification to the Bio-
systematics Research Institute, Canada Agri-
culture, Ottawa. The remainder of the material
collected was mass-reared to see if other species
of Microlepidoptera were present.

‘Permanent address: Faculty of Agriculture, Ataturk

University, Erzurum, Turkey.

MICROLEPIDOPTERA REARED

The budworm infestation had been assumed
to be of the Western budworm Choristoneura
occidentalis Free. In fact it included a second
species of Choristoneura that is probably new
and unnamed. C. occidentalis was the more
abundant of the two by a ratio of ten to one.

Eight other species of Microlepidoptera
were reared from the Douglas fir, as follows:
Griselda radicana Hein., was the most com-
mon; Dioryctria pseudotsugella Munroe, which
is sometimes a predator on the budworms
(see below); Argyrotaenia provana Kft., A. dor-
salana Dyar, Spilonota ocellana D. & SG.,
Zeiraphera hesperiana Mut. and Free.; and two
as yet unidentified species of Gelechiidae.
These species did not appear to be sufficiently
abundant individually or collectively to be a
significant pest problem.

PARASITISM AND PARASITES

Totals of 472 individuals and nine species
or species-groups of parasites emerged from the
1121 separately-reared Choristoneura larvae
and pupae (Table I). An average of 47.6 percent
of the larvae and 53.2 percent of the pupae
produced parasites. Actual pupal parasitism
may have been higher, since parasites had
already emerged from some host pupae by
the time the collections of 7 July were made.
These were not included in the count. Three
species, Glypta fumiferanae, Apanteles fumi-
feranae, and Winthemia fumiferanae, comprised
85 percent of all the parasites reared. They are
well-known parasites of budworms, as their
names indicate; the eastern spruce budworm
is C. fumiferana and the species in B.C. was
formerly classified under that name.

All the species listed in Table I and 14
additional species emerged from the mass-
reared material that included the additional

26 J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), Dec. 31, 1978

TABLE 1. Parasites that emerged from separately-reared Choristoneura spp. collected on different
dates in 1977 near Yale, B.C.

7 May: 200 2nd and 3rd instar larvae, 29 parasites: 14.5 percent parasitism.
Parasite species: Apanteles fumiferanae Vier., Glypta fumiferana (Vier.) and Diadegma sp.
13 June: 200 3rd and 4th instar larvae, 41 parasites: 20.5 percent parasitism.
Parasite species: A. fumiferanae, G. fumiferanae, Mesochorus tachypus Holm., which was a
secondary parasite on A. fumiferanae, and Gelis tenellus (Say), which was a secondary

parasite on M. tachypus.

7 July: 117 4th and 5th instar larvae, 87 parasites: 74.4 percent parasitism.
Parasite species: A fumiferanae, G. fumiferanae, Winthemia fumiferanae Tot., and Itoplectis
quadricingulata (Prov.), as a secondary parasite of G. fumiferanae.

7 July: 603 pupae, 315 parasites: 52.2 percent parasitism.
Parasite species: W. fumiferanae, Apechthis ontario (Cres.), I. quadricingulata, as a primary

parasite, and Phaeogenes hariolus (Cres.).

species of Lepidoptera. The additional species
are: Scambrus (S.) transgressus (Holm.),
Mesochorus’ tachypus Holmg., Apanteles
renaulti Mason, Microchelonus, n. sp. near
isolatus, Ascogaster argentifrons Prov.,
Elasmus atratus (How.), Dicladocerus nearcti-
cus Yshm., Polynema sp., Chrysocharis thom-
soni (Crawf.), two unidentified species of
Habrocytus, Pseudencyrtus sp., and Dendro-
cerus (Macrostigmia) sp.

DISEASES

Proportions of the larvae or pupae that died
without producing either moths or _ insect
parasites were: 7 May collection, 14 percent;
13 June, 8 percent; 6 July, 24 percent of larvae
and 10 percent of pupae. The causes of deaths
were not identified, although many of the dead
larvae contained a fungus. The incidence of
disease in the reared material is not a reliable
indication of its incidence in the field as
diseases were not surveyed in the field and
many deaths in the laboratory may have been
a consequence of rearing conditions.

PREDATION BY A PYRALID
Predation was not surveyed in the field. In
the laboratory larvae of the pyralid moth
Dioryctria pseudotsugella were observed feed-
ing on budworm prepupae and pupae at a rate
of one or two per larva per day. Tests showed
that, when given the choice, the larva prefers

to feed on fresh foliage of Douglas fir and
attacks budworms only if such foliage is not
available. In the field D. pseudotsugella nor-
mally feeds on the new needle growth that is
also eaten by the budworms but, as it appears
about a month later than the budworms and
develops more slowly, the budworms may con-
sume all its potential food supply so that if it is
to survive its only alternative is to feed on the
budworms.

ACKNOWLEDGEMENTS

The authors thank the following for their
special assistance:- At The Biosystematics
Research Institute, Dr. A. Mutuura, for iden-
tifying the Lepidoptera, Dr. W. R. M. Mason,
Dr. J. R. Barron, Dr. L. Masner, Dr. C. M.
Yoshimoto, M. Ivanochko, and H. S. Bisdee,
for the Hymenoptera, and Dr. D. M. Wood, for
the Diptera. In the Fraser Canyon, Mr. G.
Williams, of the G. Williams Logging Co.,
Spuzzum-Yale, for the practical help in select-
ing collecting sites and in tree-felling. And the
volunteers who made the collections: Dr. A. J.
McLean, University of British Columbia, Dr.
S. O’Riain, National University of Ireland,
Dr. N. Angerilli, East Kootenay Community
College, Dr. A. L. Turnbull, Simon Fraser
University, and B. Dillistone, D. Gillespie,
R. Hodgkinson, and G. Miller, graduate stu-
dents in forest pest management at Simon
Fraser University.

J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DEc. 31, 1978

27

EGG DISPERSION IN THE LARCH CASEBEARER,
COLEOPHORA LARICELLA (LEPIDOPTERA: COLEOPHORIDAE),
IN NORTHERN IDAHOY

M. W. BROWN24 AND D. L. KULHAVY2/

ABSTRACT
During 1976, a total of 3122 eggs of the larch casebearer, Coleophora
laricella, was found on 2937 needles. Of these needles, 94% had 1 egg, 5.8%
had 2 eggs, and 0.2% had more than 2. The dispersion pattern fitted a nega-
tive binomial distribution (k = 0.498). There were significantly more eggs
(x=0.01) on insolated than on shaded branches. The dispersion pattern is
due primarily to the heterogeneity of environmental factors affecting ovi-

position.

INTRODUCTION

Egg dispersion has not been examined in
previous biological and ecological investiga-
tions of the larch casebearer, Coleophora lari-
cella (Hubner), the primary insect pest of
western larch, Larix occidentalis Nutt. To
sample a species adequately, it is necessary to
know its initial dispersion. Our investigation
was combined with a project to measure the
pre-overwintering mortality of C. laricella
(Brown 1976).

METHODS

Two larch casebearer populations were in-
vestigated in mixed coniferous stands having
moderate to heavy infestations, in northern
Idaho. Stand 1, 7 km northwest of Troy, Latah
County, was in a Thuja plicata/Pachistima
myrsinites habitat type (Daubenmire and
Daubenmire 1968), with 18% (stems per ha)
larch and at an elevation of 850-975 m. Stand 2,
35 km _ southwest of Lewiston, NezPerce
County, was in an Abies grandis/P. myrsinites
habitat type, with 45% (stems per ha) larch,
and at an elevation of 1340-1365 m. Four cir-
cular 0.02 ha plots were located within each
stand. One branch within 0.5 - 2.0 m of the
ground was selected on each of six trees per
plot. On each plot, three of the branches were
shaded, three were exposed. Branches were
selected prior to oviposition to minimize
sampling bias. Each sample branch consisted
of 100 spur shoots, counted from the terminal
end including secondary branches, or 100 case-
bearer eggs, whichever came first. Eggs were
sampled four times beginning 1 July 1976 to
ascertain the pattern of dispersion. The first
two samples were made biweekly, and at four
week intervals thereafter.

+/Published with the approval of the Director of the Forest,
Wildlife and Range Experiment Station as Contribution No.
130, University of Idaho, Moscow. This research was aided by a
Grant-in-Aid of Research from Sigma Xi, the Scientific Re-
search Society of North America.

+/College of Forestry, Wildlife and Range Sciences, Univer-
sity of Idaho, Moscow, Idaho 83843.

A two-tailed paired t-test was used to com-
pare egg population density between the ex-
posed and shaded branches. For this com-
parison, we averaged the population data for
the three branches with similar exposure on the
same plot. Dispersion of the eggs was analyzed
by methods outlined by Southwood (1966),
including a Chi-square test for a Poisson (ran-
dom) distribution, the coefficient of dispersion,
and Morisita’s Index. The individual spur shoot
was used as the unit on which the calculations
were based. As the dispersion of many forest
insects is aggregated and can be described by
a negative binomial model (Waters 1955), the
parameter k was calculated for the eggs. The
statistic U was used to see how well the larch
casebearer egg dispersion fitted the negative
binomial as opposed to other models for aggre-
gated distributions. The degree of contagion
was measured using the mean crowding value
(A) based on the population mean and k.

RESULTS AND DISCUSSION

A total of 3122 eggs was recorded on 2937
needles. Of these, 2760 needles (93.97%) had
one egg, 170 (5.79% had two eggs, 6 (0.21%)
had three eggs and 1 (0.03%) had four eggs.
The number of needles with more than 1 egg is
lower than the value of 21% given by Denton
(1964) but higher than that of Jagsch (1973).
This implies a density-dependent relationship,

-since Denton worked with a larger population

and Jagsch with a smaller population than we
did. Similar to Miller and Finlayson (1977),
we also found a significant difference («<= 0.01)
in egg densities between the exposed and shad-
ed branches. The exposed branches averaged
105.92 eggs per 100 spur shoots, but the shaded
branches only 44.62 eggs.

The dispersion of C. laricella eggs fits the
negative binomial distribution and is highly
aggregated. The calculated Chi-square value
of 10,810.72 (significant X?df4547 = 4771.01,
«= (0.01) shows that dispersion does not follow
a Poisson distribution and therefore is not truly
random. The coefficient of dispersion (2.38),
Morisita’s Index (3.01) and k (0.498) all indi-

28 J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DEc. 31, 1978

cate a high degree of aggregation. Using the k
value and mean number of eggs per spur shoot
(0.686), the statistic U demonstrates that the
dispersion pattern fits the negative binomial
distribution. (If U + S.E. encompasses 0, the
negative binomial fits the data, the calculated
U =2.8 x 10-°, S.E. = 0.33.)

A X value significantly less than 2 (South-
wood 1966, Fig. 11, page 36), suggests that
aggregation was due primarily to environmen-
tal rather than behavioral factors. Environ-
mental factors that may contribute to aggrega-
tion of larch casebearer eggs include illumina-
tion (Schwenke 1958, Sloan 1965), ambient
temperature (Quednau 1967), lushness_ of
foliage (Sloan and Coppel 1965), or a combina-
tion of these factors. Gravid females are at-

tracted to the well illuminated parts of the tree
(Schwenke 1958, Sloan 1965). These are also
more likely to maintain ambient temperatures
in the optimum oviposition range of 21° to 27°
C (Quednau 1967) for longer periods than are
shaded branches. We also observed that ex-
posed branches produced lusher foliage, which
attracted gravid females (Sloan and Coppel
1965).

The aggregation of C. laricella eggs most
probably involves the attraction of gravid
females to lush, illuminated foliage. The clump-
ing of eggs on both shaded and exposed foliage
indicates that once a female finds the proper
conditions for oviposition, she continues to
oviposit in the same area, this resulting in the
observed high degree of aggregation.

REFERENCES
Brown, M. W. 1976. A partial life table for the larch casebearer Coleophora laricella (Lepidoptera:
Coleophoridae) with notes on egg dispersion, M.S. Thesis, Univ. of Idaho, Moscow, ID.
Daubenmire, R. and J. B. Daubenmire. 1968. Forest vegetation of eastern Washington and north-
ern Idaho. Washington State Univ. Agric. Exp. Sta. Tech. Bull. 60. 140 pp.

Denton, R. E. 1964. The larch casebearer in western larch forests. Northern Rocky Mountain
Region, A problem analysis. (unpub.) U.S. Dep. Agric. For. Serv. Intermountain Forest
and Range Exp. Sta., Moscow, ID 24 pp.

Eidmann, H. H. 1965. Ecologic and physiologic studies on the larch casebearer, Coleophora lari-
cella Hbn. (Eng. Transl.) Studia Forestalis Suecica. No. 32. 322 pp.

Jagsch, A. 1973. Population dynamics and parasite complex of the larch casebearer in the natural
area of distribution of European larch. (Eng. Transl.) Z angew. Entomol. 73: 1-42.

Miller, G. E. and T. Finlayson. 1977. Distribution of Coleophora laricella (Lepidoptera: Coleophori-
dae) and its major parasites in the crowns of western larch in British Columbia. J.
Entomol. Soc. British Columbia 74: 10-15.

Quednau, F. W. 1967. Notes on mating, oviposition, adult longevity, and incubation period of eggs
of the larch casebearer, Coleophora laricelia (Lepidoptera: Coleophoridae), in the labora-
tory. Can. Entomol. 99: 397-401.

Schwenke, W. 1958. Uber die Standortabhangigkeit des Massenwechsels der Larchenminiermotte,
Coleophora laricella Hbn., und der Ahorneule, Acronyta aceris L. (Eng. Abstr.) Beitrz.
Z. Entomol. 8: 241-290.

Sloan, N. F. 1965. Biotic factors affecting populations of the larch casebearer Coleophora laricella
Hbn. in Wisconsin. Ph.D. Dissertation, Univ. of Wisconsin, Madison, Wisconsin. 193 pp.

Sloan, N. F. and H. C. Coppel. 1965. Ovisposition patterns and egg predation of the larch case-
bearer (Coleophora laricella Hbn.) in Wisconsin. Univ. Wisconsin Res. Notes 124. 4 pp.

Southwood, T. R. E. 1966. Ecological methods, with particular reference to the study of insect
populations. Chapman and Hall. London.

Waters, W. E. 1955. Sequential sampling in forest insect surveys. Forest Sci. 1: 68-79.

Webb, F. E. 1953. An ecological study of the larch casebearer, Coleophora laricella Hbn. (Lepidop-
tera: Coleophoridae). (unpub.) Ph.D. Dissertation University of Michigan, Ann Arbor,
Michigan. 210 pp.

J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DEc. 31, 1978 29

PRE-OVERWINTERING MORTALITY IN THE
LARCH CASEBEARER, COLEOPHORA LARICELLA
(LEPIDOPTERA: COLEOPHORIDAE), ON WESTERN LARCH
IN NORTHERN IDAHO.!

M. W. BROWN? AND D. L. KULHAVY?

ABSTRACT

During 1976, continuous sampling of the same population cohort showed
a 68% mortality in the pre-wintering larch casebearer, Coleophora laricella,
in northern Idaho. The major mortality factors were density-independent;
these were: premature needle drop caused by the needle diseases Meria
laricis and Hypodermella laricis (18%); non-viable eggs (10%); and dis-
lodgment of the eggs from the branch (10%). Other factors were: predation,
desiccation, ripening and fall of the needles, intraspecific competition, loss of
larvae moving between needles, and larch-willow rust.

INTRODUCTION

The larch casebearer, Coleophora laricella
(Hubner), is the primary insect pest of western
larch, Larix occidentalis Nutt. Originally found
only in the eastern European highlands on
European larch, L. decidua Mill., C. laricella is
now nearly Holarctic in distribution (Schindler
1968).

Although researchers have investigated the
biology and ecology of C. laricella (Webb 1953,
Eidmann 1965, Sloan 1965), and a life table was
prepared in Austria by Jagsch (1973), little is
known about pre-overwintering mortality in
western North America. Limited data only are
available on egg mortality from predation, dis-
logdment and failure of the eggs to hatch
(Baird 1923, Sloan 1965, Denton 1972). Preda-
tion, fungi, desiccation, autumn needle fall and
intraspecific competition cause mortality dur-
ing the larval mining stage (Jung 1942, Webb
1950, Sloan 1965, Jagsch 1978).

The purpose of our study was to identify
the mortality factors in the egg, mining and
autumn casebearing stages of the larch case-
bearer, in northern Idaho.

METHODS

Two sampling areas were established in
sapling stands of western larch with moderate
to heavy casebearer infestations. Stand 1 was
located 7 km northwest of Troy, Latah County,
in a Thuja _ plicata/Pachistima myrsinites
habitat type (Daubenmire and Daubenmire
1968); it had 18% (stems per ha) larch and
ranged from 850 to 975 m elevation. Stand 2
was located 35 km southwest of Lewiston, Nez
Perce County, in an Abies grandis/P. myrsin-
ites habitat type; it had 45% (stems per ha)

‘Published with the approval of the Director, Forest, Wild-
life and Range Experiment Station as Contribution No. 131,
University of Idaho, Moscow. This research was aided by a
Grant-in-Aid of Research from Sigma Xi, The Scientific
Research Society of North America.

College of Forestry, Wildlife and Range Sciences, Univer-
sity of Idaho, Moscow, Idaho 83843.

in larch and ranged from 1340 to 1365 m eleva-
tion.

Four circular 0.02-ha plots were located
within each stand. One branch within 0.5-2.0 m
of the ground was selected on each of six trees
per plot. Three branches on each plot were ex-
posed to the sun, the other three were shaded.
Each sample branch consisted of 100 spur-
shoots, counted from the terminal and includ-
ing secondary branches, or 100 casebearer eggs,
whichever came first. A barrier was erected at
the end of the 100 spur shoots (or 100 eggs).
The larch casebearers on these 48 branches
constituted our population cohort. The branch-
es were selected prior to oviposition to mini-
mize sampling bias.

We sampled the same population cohort six
times beginning 1 July 1976, to ascertain the
degree and the cause of mortality in C. lari-
cella. Counts were made on individual spur
shoots to follow the development of individual
casebearers. The first two samples were made
biweekly, and at four-week intervals thereafter.
Sampling continued until the first week of
November when the larch needles had yellowed
and begun to fall. By this time, nearly all the
larvae had migrated to overwintering sites
on the branch. Notes were made on the
probable causes of mortality.

Our cohort samples differed from the
samples used for other lepidopteran needle
miners (Stark 1958, Jagsch 1973), in that we
sampled a single cohort during the period, and
thus avoided destructive sampling. Our method
permitted the incorporation of more observa-
tional data and a more accurate accounting
for the population decline.

Halfway through the sampling period one
exposed sample branch was vandalized. Mor-
tality of the mining and casebearing stages on
the missing branch was estimated by averaging
the mortality percentages from the other two
exposed branches on the plot.

30

TABLE I.
in northern Idaho, 1976.
Number
Age alive at
Interval beginning of x
x 1
x
Egg 3122
Mining 2192
Larvae
Fall 1088
Casebearing
Larvae
Entering 1009
Winter

Mostly dislodgment

J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), Dec. 31, 1978

Pre-overwintering mortality factors for the larch casebearer

Factor Number d* as
responsible dying See
for <d during x
de = on eet
x
Non-viable
No-hatch 142 4.6
Empty 116 Sal.
Abnormal 48 Else:
Total 306 9.8
Predation 98 ont!
Needle Cast 176 Dia0
Needle Rust 36 12
Dislodged 10 0.3
nenest 304 Oe7
930 291m
In-transit 245 PLZ
Needle Cast 380 1723
Needle Rust 7 0.8
Intraspecific
Competition 55 ag)
Needle Drop dade D2
Dead 7Z Boe
Darvon 2222 1 a
1104 50°53
Needle Cast 19 1.8
Needle Drop 11 120
Dislodged 6 0.6
Dead 7 0.6
Unknown” __ 36 Bis)
79 113
Total Mortality, 2113 OV) ae

Mostly in-transit mortality

3

Mostly needle drop and dislodgment

J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DEc. 31, 1978

RESULTS

Approximately two-thirds (67.7%) of the co-
hort died between oviposition and the attain-
ment of the overwintering stage (Table I).
Nearly 30% of the eggs did not hatch for
various reasons and of those that did, more
than one-half of miners failed to form a case.
More than 7% of those forming a case did not
survive to winter. Density-dependent factors
accounted for 4.9% mortality, whereas density-
independent factors were responsible for
62.8% mortality (Table II).

TABLE II.

31

Density-Independent Factors

Needle-cast fungi, Meria laricis Vuill. and
Hypodermella laricis v. Tub., caused a decline
of 18.4% in the cohort by inducing premature
needle drop. Meria laricis was the more im-
portant. Nearly all branches were infected.
Several branches, completely defoliated, had
the entire resident casebearer population
destroyed. Needle casts were most abundant
in the lower crown.

Non-viable eggs, 9.8% of the cohort (29.7%
of the eggs), were divided into three categories;

Summary of pre-overwintering mortality factors acting on

the larch casebearer, northern Idaho, 1976.

Stage No. Percent
Factor Re reepeae Killed Mortality
Density-Independent
Needle Cast e,m,c 2/5 18.4
Non-viable e
No-hatch ae Ie 6)
Empty 116 ony,
Abnormal 48 me)
Total 306 9.8
In-transit m 245 ee)
Needle Drop m,c IBS: ZO
Dead m,c 78 PES)
Needle Rust e,m 5S Pe
Dislodged e,c 16 Om
a 304 9.7
Unknown m 222 el
c 36 ee
Density—Dependent
Predation e 98 Bal
Intraspecific
Competition m 5) 18
Total e,m,;c PAIES 6/27
e ='ege stage, m = mining stage, c = casebearing stage

Mostly dislodgment

Mostly in-transit mortality

Mostly needle drop and dislodgment

32 J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DEc. 31, 1978

no-hatch, empty and abnormal. No-hatch eggs
had normal shape and color, but simply failed
to hatch. Empty eggs were pale and trans-
lucent when first observed, apparently lacking
normal contents. Abnormal eggs were either
small and withered, or desiccated.

Mining and casebearing larvae still attached
to the needles during autumn needle fall
accounted for a 4.0% loss. Larvae in this
category either failed to form a case or were
attached to a needle rather than a branch for
overwintering.

Larch-willow rust, caused by Malampsora
paradoxa Diet. and Holw., caused a 1.7% mor-
tality in the same manner as needle casts. This
rust affected only the egg and early mining
stages.

Some eggs and casebearing larvae were dis-
lodged by mechanical disturbances. Much of
the unknown egg mortality may have been due
‘to dislodgment.

Miners that died while moving between
needles (in-transit mortality) accounted for
7.9% of the cohort. This mortality factor, due to
either dislodgment or desiccation, was esti-
mated from mined-out needles without a larch
casebearer nearby.

Larvae in their mines or cases, but not feed-
ing between sample periods were recorded as
dead. This mortality was caused by desiccation
or diseases.

Density-Dependent Factors

We did not directly observe predation. Eggs
placed in this category appeared healthy when
first observed, but were pale and translucent at
a later examination. Because of the similarity
in appearance of these eggs and empty eggs,
predators may have caused some of the mor-
tality categorized as non-viable.

Intraspecific competition resulted when
more than one egg hatched on the same needle.
Usually only the larva located near the needle
base survived. When more than one larva sur-
vived, one, or both, migrated to a fresh needle.

DISCUSSION

The high level of in-transit mortality is con-
trary to the findings of Webb (1953), who found
little migration in the mining stage. We con-
cluded that in-transit mortality was induced
by: (1) dense aggregation of the eggs (Brown
1976), and (2) desiccation of the needles from
diseases. The combined effect of these factors
increased migration of the larvae which led to
increased exposure and predation.

Dislodgment of eggs accounted for 0.3% of
the observed mortality. However, including the
unknown egg mortality, 8-10% of the cohort
was lost in this manner.

The value of 3.1% predation (6.9% including
eggs classified as empty) was considerably
less than had been previously reported (15%
by Webb 1950; 5-40% by Eidmann 1965; 22%
by Sloan 1965; 16% by Denton 1972). Mites
and true bugs were the most important preda-
tors, with a large red mite, Bdella muscorum
Ewing, apparently the most important in Idaho
(Denton 1972). Webb (1953) considered that
predation was an important biological control
factor of C. laricella. Predation was difficult
to ascertain, but possible predators (spiders,
predaceous mites, true bugs, and thrips, Aeolo-
thrips sp.) were present on our sample branch-
es.

Failure of the eggs to hatch was a major
cause of mortality. Jagsch (1973) attributed
egg mortality to hatching difficulties; Eidmann
(1965) attributed it to disturbance in develop-
ment cf the embryo; or simply to infertility or
non-viability. We divided egg mortality into
three categories based on appearances (Table
1);
Although less than one-third of our cohort
survived to the over-wintering stage, the pre-
overwintering period is not considered critical
for population regulation. Density-independent
factors were primarily responsible for the
population decline, and as Nicholson (1958)
and Solomon (1957) state, population regula-
tion can only come about through the action of
density-dependent mortality factors. Quednau
(1967) also concluded that regulating, natural
control factors do not act upon the egg stage of
the larch casebearer. Following the same
population cohort, as we did, allowed for a more
accurate accounting of mortality, than did des-
tructive sampling, and with less disruption
to the population.

ACKNOWLEDGEMENTS
We thank our colleague, Dr. E. R. Canfield,
of this institution, for identifying the needle
diseases; and Dr. K. O’Neill, U.S.D.A. Agri-
cultural Research Service, Plant Pest Survey
and Detection, Beltsville, Maryland, for identi-
fying the thrips.

J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), Dec. 31, 1978 33

REFERENCES

Baird, A. B. 1923. Some notes on the natural control of the larch sawfly and larch casebearer in
New Brunswick in 1922. Acadian Ent. Soc. Proc. Nova Scotia (1922) 8:158-171.

Brown, M. W. 1976. A partial life table for the larch casebearer, Coleophora laricella (Lepidoptera;
Coleophoridae) with notes on egg dispersion. M.S. Thesis, Univ. of Idaho, Moscow, Idaho.

Daubenmire, R. and J. B. Daubenmire. 1968. Forest vegetation of eastern Washington and north-
ern Idaho. Washington State Univ. Agric. Exp. Sta. Tech. Bull. 60. 104 pp.

Denton, R. E. 1972. Establishment of Agathis pumila (Ratz.) for control of larch casebearer and
notes on native parasitism and predation in Idaho. U.S. Dep. Agric. For. Serv. Inter-
mountain Forest and Range Exp. Sta. Res. Note INT-164. 6 pp.

Eidmann, H. H. 1965. Ecologic and physiologic studies on the larch casebearer, Coleophora lari-
cella Hbn. (Eng. Transl.) Studia Forestalis Suecica. No. 32. 322 pp.

Jagsch, A. 1973. Population dynamics and parasite complex of the larch casebearer in the natural
area of distribution of European larch. (Eng. Transl.) Z. angew. Ent. 73:1-42.

Jung, W. 1942. Contributions to the knowledge of the larch casebearer (Coleophora laricella Hbn.).
(Eng. Transl.) Z. angew. Ent. 29:475-517.

Nicholson, A. J. 1958. Dynamics of insect populations. A. Rev. Ent. 3:107-136.

Quednau, F. W. 1967. Notes on mating, oviposition, adult longevity, and incubation period of eggs
of the larch casebearer, Coleophora laricella (Lepidoptera: Coleophoridae), in the laboratory.
Can. Ent. 99:397-401.

Schindler, U. 1968. Population change in a typical perennial forest pest, the larch casebearer. (Eng.
Transl.) Z. angew. Ent. 61:380-386.

Sloan, N. F. 1965. Biotic factors affecting populations of the larch casebearer Coleophora laricella
Hbn. in Wisconsin. (Unpub.) Ph.D. Dissertation, University of Wisconsin, Madison, Wis-
consin. 193 pp.

Solomon, M. E. 1957. Dynamics of insect populations. A. Rev. Ent. 2:121-142.

Stark, R. W. 1958. Life tables for the lodgepole needle miner Recurvaria starki Free. (Lepidoptera:
Gelechiidae). Proc. X Internat]. Cong. Ent. (1956) 4:151-162.

Webb, F. E. 1950. The biology of the larch casebearer Coleophora laricella Hubner in New Bruns-
wick. (Unpub.) M.S. Thesis, University of Michigan, Ann Arbor, Michigan. 50 pp.

Webb, F. E. 1953. An ecological study of the larch casebearer, Coleophora laricella Hbn. (Lepi-
doptera: Coleophoridae). (Unpub.) Ph.D. Dissertation, University of Michigan, Ann
Arbor, Michigan. 210 pp.

EXAMINATION OF DOUGLAS-FIR CLONES
FOR DIFFERENCES IN SUSCEPTIBILITY
TO DAMAGE BY CONE AND SEED INSECTS

A. F. HEDLIN AND D. S. RUTH

Environment Canada
Canadian Forestry Service
Pacific Forest Research Centre
Victoria, B.C. V8Z 1M5

ABSTRACT

In 1974 and 1976, Douglas-fir cones from 51 clones and 150 clones, res-
pectively, were collected and determinations were made of the percentage
of seed damaged by the cone insects Barbara colfaxiana, Contarinia ore-
gonensis, C. washingtonensis and Megastigmus spermotrophus. Although
statistically significant differences in percentage of damaged seeds were
detected among clones, these differences were not great enough to be of
practical importance.

34 J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DEc. 31, 1978

RESUME
En 1974 et en 1976, dans respectivement 51 et 150 clones, les auteurs
récoltérent des cdnes de Douglas et déterminerent le pourcentage de graines
endommagees par les Insectes Barbara colfaxiana, Contarinia oregonensis,

C. washingtonensis et Megastigmus spermotrophus.

Malgre que des

differences statistiquement significatives de pourcentages de graines en-
dommagees fussent détectées parmi les clones, les différences ne se revele-

rent pas importantes en pratique.

Significant differences have been reported
in cone insect attack among clones, i.e. a group
of genetically identical plants derived asexually
from a single individual (Snyder, 1972), in slash
pine, Pinus elliottii Englm. var. elliottii (De
Barr et al., 1972; Merkel et al., 1965). Thus
the present study was conducted to determine
if a similar situation is true in seed orchards on
Vancouver Island, British Columbia. Fifty-one
Douglas-fir clones were sampled in 1974 and
150 in 1976; only 35 of these were sampled in
both years but none in 1975, because of a poor
cone crop. Twenty cones were taken from each
clone and, where possible, from five ramets,
i.e. an individual member of a clone, per clone.
Damage in percentage of seed per cone, was
determined for four common Douglas-fir insect
pests: the cone moth, Barbara colfaxiana
(Kearfott); the cone gall midge, Contarinia
oregonensis Foote; the cone scale midge, C.
washingtonensis Johnson, and the seed chal-
cid, Megastigmus spermotrophus Wachtl.

The data were analyzed on the basis of per-
cent damaged seeds per cone, after being trans-
formed, to correct for heterogeneity of
variance, to the limited arcsin. The means were
compared using the Student-Neuman-Keuls’
multiple range test, with extension suggested

by Kramer for unequal replications (Steel and
Torrie, Principles and Procedures of Statistics,
110-114. 1960).

Because of the size of the experiment (four
insect pests x three orchards x 166 total clones)
and because so few significant differences were
detected, we have summarized the results
verbally; the numerical data are available from
the authors. The results showed that: damage
by the cone moth and cone scale midge did not
differ significantly among any of the clones
within the same orchard; damage by the cone
gall midge did not differ significantly among
clones except for one clone which suffered more
damage than the others in the same orchard;
damage by the seed chalcid was significantly
more severe for only two clones in the same
orchard. Because the analyses showed only
minor differences in extent of insect damage
among clones, these differences were generally
of no practical importance.

ACKNOWLEDGEMENTS
We acknowledge with thanks the assistance
of C. Simmons, J. Sutherland and T. A. D.
Woods, Pacific Forest Research Centre, Vic-
toria, B.C., in analyzing the statistics and
interpreting the data.

REFERENCES
DeBarr, G. L., E. P. Merkel, C. H. O’Gwynn and M. H. Zoerb, Jr. 1972. Differences in insect
infestation in slash pine seed orchards due to phorate treatment and clonal variation. For.

Sci. 18: 56-64.

Merkel, E. P., A. E. Squillace and G. W. Bengston. 1965. Evidence of inherent resistance to
Dioryctria infestation in slash pine. Proc. 8th South. Conf. For. Tree Improvement. pp 96-

99, Savannah, Ga.

Snyder, E. G. 1972. Glossary for forest tree improvement workers. South. For. Expt. Sta. Forest

Service, USDA, New Orleans, La.

}

J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DEc. 31, 1978 5

LABORATORY EVALUATION OF GEOCORIS BULLATUS'; AND
NABIS ALTERNA TUS?; AS PREDATORS OF L YGUS*,*/

GEORGE TAMAKI”, D. P. OLSEN*,, AND R. K. GUPTA*,

ABSTRACT
Adults of Geocoris bullatus were not effective predators against late
nymphs and adults of Lygus, but adults of Nabis alternatus were effective
against these stages. Both predators were effective against the young
Lqgus nymphs. Males of N. alternatus were almost as successful as females
against small prey but were less effective against the late stage Lygus.

INTRODUCTION

Since pest management programs are being
developed for alfalfa grown for seed in central
Washington (Johansen et al. 1976), there is a
need to determine the impact of these 2 groups
of predators on populations of Lygus. In the
laboratory study reported here, we attempted
to establish what life stages of Lygus are most
vulnerable to predation by Geocoris and Nabis
spp.

MATERIALS AND METHODS

Studies were conducted in pint-size cages
(Tamaki and Butt 1977) containing an alfalfa
bouquet made of 4-5 stems in bloom or of seed
bearing terminals cut 7-10 cm long. Such
heavily packed stems provided both food and
shelter for the Lygus and also made a more
natural environment than the near-empty
cages or petri dishes commonly used as arenas
for studies of predator-prey interaction. Al-
though only 1 predator was added to each cage,
the number of Lygus was varied according
to the size of the predator and prey. The intent
was always to provide more prey than the
predator could consume.

Each treatment of a particular life stage of
the predator or prey was tested 2 times, 10
replicates per test, and each test lasted 5 days.
All cages were checked daily to determine
the condition of the insects and for main-
tenance. Cages were kept on_ laboratory
benches under daylight fluorescent lights
(16-hr photophase) at an average temperature
of 24°C (range 18-32°).

For each treatment with a predator, a
corresponding treatment without predators
but with the same number of Lygus of the same
stage was established. We were thus able to
determine a corrected rate of predation by de-
termining Lygus mortality in both situations.

Geocoris bullatus and Nabis alternatus
were the predators used because they were the

'/ Hemiptera: Lygaeidae

*/ Hemiptera: Nabidae

5/ Hemiptera: Miridae

‘/In cooperation with the College of Agriculture Research
Center, Washington State University, Pullman 99164.

*/Yakima Agricultural Research Laboratory, Agric. Res.
Serv., Yakima, WA 98902.

°/Dept of Entomology, Washington State University, Pull-
man 99164.

most readily available species. They were
collected in the field on alfalfa and red clover
and from beneath the trees in an orchard. No
work was conducted with the lst instars of
either Geocoris or Nabis because they were
difficult to collect and equally difficult to
observe. Lygus bugs were collected from seed-
bearing lambsquarters, Chenopodium album
L., and pigweed, Amaranthus retroflexus L.,
and were a mixture of Lygus elisus Van Duzee
and L. hesperus Knight; L. elisus was pre-
dominant. We did not separate the collected
nymphs so all are referred to as Lygus or lygus
bug. During the collections, some field obser-
vations were made.

RESULTS AND DISCUSSION

Geocoris

Geocoris adults caged with large Lygus,
either 4th- and 5th-stage nymphs or adults,
consumed so few prey that the corrected mor-
tality (Table 1) was probably all the result of
laboratory conditions. In fact, Geocoris adults
were not observed feeding on adult or late
instar Lygus but were frequently observed
feeding on young Lygus.

All other stages of Geocoris from 2nd-to
Sth-stage nymphs did feed on young (2nd-3rd
instars) Lygus nymphs.

Nabis

Since Perkins and Watson (1972) studied
predation by Nabis nymphs in Arizona, we
concentrated on the predation by the adult
stage in our study (Table 2). Nabis adults con-
sumed relatively few Lygus adults, but the
rate was 3 times that of Geocoris adults. They
also consumed more late-instar (5th and 4th)
nymphs. However, Nabis adults consumed 14
times as many 2nd-stage Lygus nymphs as
adult Lygus.

We also made a special test in which 5th-
stage Nabis were caged with the 4th or 5th
stages of Lygus so we could compare our
results with those of Perkins and Watson
(1972). Our 5th-stage Nabis consumed an avg
of 0.41 + 0.12 S.E. 5th-stage Lygus per day
compared with 0.9 per day in Perkins and
Watson’s test or an avg of 1.33 + 0.19 S.E.
Ath-stage Lygus per day compared with 2.9
per day in their test. The data of Fye (1978),

36 J. ENTOMOL. Soc. Brit. COLUMBIA 75 (1978), DEc. 31, 1978

TABLE 1. Predation rates (corrected) of life stages of Geocoris
builatus feeding on! stages or byeus «
——— gg...
No. consumed
Life stage Life stage per day
of Geocoris of Lygus (averagennasy -E.))
SESE ee re a
Adult Adult 087% 1205
Adult 4th-5Sth 1027 See!
Sch 2nd-3rd Leo eo
4th 2nd-3rd Bic) copa Mu
2nd-3rd 2nd-3rd ee

who also studied the feeding rates of Nabis on
Lygus in Arizona, were likewise more in agree-
ment with those of Perkins and Watson than
with ours. Therefore, the consumption rates of
Nabis in Washington were about '% those re-
ported by 2 groups of workers in Arizona. The
difference could reflect geographic differences,
species differences, or differences in tempera-
ture (constant temperatures of 25° and 28° C
for Perkins and Watson and Fye, respectively,
and our range from 18° to 32° with an avg of
24°C). However, we feel that the heavy foliage

TABLE *25

of alfalfa in the cages was probably the main
cause of the lower efficiency of the predator.
Thus our values may be more comparable to
feeding rates in the field.

Nabis females consumed more prey than
males (Table 3). However, the difference
between the sexes was less when they were
caged with smaller Lygus nymphs. Apparently,
the male is almost as successful as the female
against small prey but is less effective against
larger prey.

Predation rate €corrected) of adul reer

Nabis alternatus preying on stages of Lygus.

Life stage

No. consumed per day

of Lygus (Average =°S 2)
Adult 2314 205
Sth glen O)oy nz ges 1)
et 2.08 aiek
3rd 26D tO
2nd Teens sy

J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), Dec. 31, 1978 37

TABLE 3. Predation rate of adult male and female
Nabis alternatus on life stages of Lygus.

Life stage Average no. Ob byeus killed % consumed
of Lygus * Nabis ¢ Nabis by male
Adult 43 1025 5
oy Be KBs 3 »f00 82
4th Date ie G 40
3rd 3.40 Deo 43
2nd 52.06 be c 00 48
CONCLUSION tors and on the age distribution of the Lygus

Although adults of Geocoris occasionally
prey on 4th, 5th, and adult stages of Lygus,
this species is primarily a predator of the

population.

Indexing Words:

smaller nymphal stages of Lygus (lst-3rd in-
stars). Nabis is an effective predator against
large Lygus (4th, 5th and adults) but is more
successful against smaller Lygus. The impact
of Geocoris and Nabis on populations of Lygus
therefore depends both on the number of preda-

Lygus

Geocoris bullatus
Geocoris pallens
Nabis alternatus
Predators
Biological control

REFERENCES

Fye, R.E. 1978. Analysis of cotton insect populations in southern Arizona: Impact of predators
and other mortality factors. USDA Tech. Bull. (In press).

Johansen, C. A., E. C. Klostermeyer, A. H. Retan, and R. R. Madsen. 1976. Integrated pest
management on alfalfa grown for seed. Wash. State Univ., Coll. Agric. and Coop. Ext.
Serv. EM 3755, 8 p.

Perkins, P. V., and T. F. Watson. 1972. Nabis alternatus as a predator of Lygus hesperus. Ann.
Entomol. Soc. Am. 65: 625-9.

Tamaki, G., and B. A. Butt. 1977. Biology of the false celery leaf tier and damage to sugarbeets.
Environ. Entomol. 6: 35-8.

38 J. ENTOMOL. Soc. Brit. COLUMBIA 75 (1978), Dec. 31, 1978

BUPRESTIDAE OF SOUTHERN VANCOUVER ISLAND

P. EVERSON

Department of Biology, University of Victoria,
Box 1700, Victoria, B.C.

ABSTRACT
This paper lists the Buprestidae known to occur on Southern Vancouver
Island, British Columbia, with their hosts. Represented are the following
tribes: Buprestini (15 spp.); Chrysobothrini (6 spp.); Acmaeoderini (1 sp.);

and Agrilini (1 sp.).

INTRODUCTION

Southern Vancouver Island comprises that
area of the island south of latitude 49.5°. This
area includes two major biotic zones, the coast-
al forest and the gulf island lowlands (Cannings
and Stuart 1977). These zones have moderate
temperatures and abundant winter rain with a
characteristic Vancouveran fauna which is
noted for its diversity of geobious and hydro-
bious beetles (Hatch 1953).

References to the Buprestidae of Southern
Vancouver Island are brief. They include those
of Walker (1866), LeConte (1869), Holland
(1888), and Evans (1957), but Hardy (1927,
1942) compiled an annotated list of his captures
in the greater Victoria area with notes on host
species.

This paper expands the work of Hardy to
include capture records from the southern part
of the island. Specimens examined came from
the collections of the University of Victoria
(UV), the British Columbia Provincial Museum
(PM), the Pacific Forest Research Center (PF),
and the Saanichton Research Station (S).
Figures in parentheses represent the number
of specimens in the collection. The identifica-
tions and classification used in this list follow
Barr (1971). The place names may be found in
the Gazetteer of British Columbia and are
printed in boldface type.

Family Buprestidae
Subfamily Buprestinae
Tribe Buprestini

Chalcophora angulicollis LeC.: Victoria,
4-VIII-29, W. H. A. Preece, (S) (2); ?-VIII-33,
W. Downes, (S) (1); Errington, 6 to 29-V-29,
G. H. Larnder, (PM) (12); Sidney, 5-VI-27,
A. W. Nicholls, (PM) (5); Victoria, 24-V-34,
G. A. Hardy, new cut fir, (PM) (3); Nanaimo,
Holland (1888); Walker (1866); LeConte
(1869); Wellington, anonymous (1906); Hosts:
Pinus contorta, P. ponderosa, Abies grandis,
A. concolor and Pseudotsuga menziesii (Barr
1971).

Trachykele blondeli Mars.: Errington, 3-
VII-51, G. H. Larnder, (PM) (1); Shawnigan L.,
30-V-26, G. A. Hardy, (PM) (1); Hosts: Thuja
plicata, Cupressus and Juniperus (Barr 1971).

Trachykele nimbosa Fall: Langford, 2-VI-60,
D. Evans, in flight, (PF) (1); Hosts: A. grand-
is, A. concolor, A. magnifica and T. merten-
siana (Barr 1971); Possibly a new island record.

Dicerca tenebrosa Kby.: Nanaimo, Holland
(1888); Wellington, anonymous (1906); Hosts:
numerous coniferous spp. (Barr 1971).

Dicerca sexualis Cr.: Victoria, 23-VI-34,
G. A. Hardy, on A. grandis, (PM) (10); Depar-
ture Bay, ?-VI-08, W. Taylor, (PM) (1).

Dicerca crassicollis LeC.: Errington, 5-V1-29,
21-III-40, G. H. Larnder, (PM) (17); LeConte
(1869).

Dicerca tenebrica Kby.: Mesachi L., 12-VII-

67, R. Morley, on beach, (UV) (1); Possibly a

new island record.

Poecilonota fraseri Chamb.: Victoria, 20-
VIII-26, G. A. Hardy, on willow, (PM) (2);
Evans (1957); Hosts: Salix spp. (Barr 1971).

Buprestis aurulenta L.: Victoria, 4-VIII-29,
W. H. A. Preece, (S) (3); G. A. Hardy, (PM)
(3); Shawnigan L., 14-VII-09, (S) (1); Errington,
1-VI-29, G. H. Larnder, (PM) (6); Sidney, 26-V-
25, G. A. Hardy, on new-cut fir, (PM) (11),
Millstream, G. A. Hardy, (PM) (9); Walker
(1866); LeConte (1869), Nanaimo, Holland
(1888); Wellington, anonymous (1906); Hosts:
Pseudotsuga menziesii, Abies grandis, Pinus
ponderosa, P. jeffreyi, P. labertiana, P. contorta
and P. flexilis (Barr 1971).

Buprestis langi Mann.: Metchosin, 23-VIII-
29, W. J. R. Preece, (S) (1); Duncan, 20-VIII-70,
K. J. R. Bartlett, on the ground, (UV) (1);
Victoria, 3-VIII-67, R. Ring, in grass, (UV) (1);
20-VIII-68, J. M. Campbell, on ground, (UV)
(1); Walker (1866); LeConte (1869); Wellington,
anonymous (1906); Host: P. menziesii (Barr
1971).

Buprestis adjecta LeC.: Errington, 4-VIII-
46, G. H. Larnder, (PM) (1); Parksville, 4-VIII-
46, G. H. Larnder, (PM) (1); Nanaimo, 16-VIII-
98, W. Taylor, (PM) (2); Sidney, 31-VII-25,
W. C. Cornfield, (PM) (1); LeConte (1869),
Wellington, anonymous (1906); Hosts: P. pon-
derosa, P. jeffreyi, P. contorta and Picea engel-
manni (Barr 1971).

Buprestis rusticorum Kby.: Saanich, 6-VIII-
wi, W. H. A. Preece, (S) (2); Caycuse, 3-VIII-62,
E. D. A. Dyer, in flight, (UV) (1); Mesachi L.,
5-VII-68. R. Storey, (UV) (1); Millstream, 2-

J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DEc. 31, 1978 39

VIII-25, G. A. Hardy, New-cut Douglas fir,
(PM) (8); Errington, 28-VIII-28, G. H. Larnder,
(PM) (7); Walker (1866); Hosts: P. ponderosa,

Pseudotsuga menziesii and Abies grandis
(Barr 1971).
Melanophila acuminata DeG.: Nanaimo,

22-VIII-99, A. W. Hanham, (PM) (1); Duncan,
10-VIII-18, A. W. Hanham, (PM) (1); Nanaimo,
Holland (1888); Hosts: Pinus spp., Abies spp.
and Picea spp. (Barr 1971).

Melanophila drummondi Kby.: Sidney, 24-
VII-26, W. H. A. Preece, (S) (3); 25-V-25, G. A.
Hardy, (PM) (7); Victoria, ?-V-71, R. Ring,
(UV) (2); 3 to 10-VI-34, G. A. Hardy, new-cut
fir, (PM) (13); Errington, 13-V-51, G. H. Larn-
der, (PM) (5); Goldstream, 3-VI-24, G. A.
Hardy, (PM) (7); Nanaimo, Holland (1888);
LeConte (1869); Hosts: numerous conifer spp.
(Barr 1971).

Anthaxia aeneogaster Cast. et Gory: Saan-
ich, 13-V-29, W. H. A. Preece, (S) (1); Shawni-
gan L., 11-VI-29, W. Downes, (S) (1); Erring-
ton, 14-IV-51, G. H. Larnder, on dandelion,
(PM) (7); Victoria, 14-V-27, G. A. Hardy, (PM)
(2); Hosts: Pinus spp. (Barr 1971).

Tribe Chrysobothrini

Chrysobothris sylvania Fall: Sidney, 21-VI-
25, W. H. A. Preece, on fresh-cut Douglas fir,
(S) (1); Millstream, 2-VIII-25, G. A. Hardy, on
new-cut fir, (PM) (1); Host: Pseudotsuga men-
ziesii (Barr 1971).

Chrysobothris carinipennis LeC.: Sidney,
8-VIII-25, G. A. Hardy, new-cut Douglas fir,
(PM) (3).

Chrysobothris pseudotsugae Van Dyke:

Sidney, 2-V-26, W. H. A. Preece, on fresh Doug-

las fir, (S) (2); Victoria, 3-VII-34, G. A. Hardy,
new-cut Abies grandis, (PM) (4); Host:
Pseudotsuga menziesii (Barr 1971).

Chrysobothris femorata (01.): Sidney, 21-

VII-25, W. H. A. Preece, Douglas fir, (PM)
(1); Victoria, 21-VI-34, G. A. Hardy, apple tree,
(PM) (1); Hosts: numerous deciduous spp.
(Barr 1971).

Chrysobothris nixa Horn: Millstream, 1-
VIII-25, G. A. Hardy, in a gallery in Thuja
plicata, (PM) (2); Hosts: Libocedrus decurrens,
Thuja plicata and Juniperus occidentalis (Barr
OWA

Chrysobothris caurina Horn: Cowichan
L., 20-VII-40, K. Graham, Pinus contorta,
(PF) (1); Wellington, anonymous (1906);
Hosts: Pinus spp., Abies concolor, Larix occt-
dentalis, Pseudotsuga menziesii and Tsuga
mertensiana (Barr 1971).

Subfamily Acmaeoderinae
Tribe Acmaeoderini
Chrysophana placida LeC.: Victoria, 17-

VI-69, B. Cousins, (UV) (1); 5-VI-67, R. Morley,
(UV) (1); 10-VI-34, G. A. Hardy, Abies grandis,
(PM) (4); Errington, 6-III-39, 24-VII-44, 9-
VI-38, 2-VII-49, G. H. Larnder, (PM) (1); Dun-
can, 31-III-25, 16-III-18, A. W. Hanham, (PM)
(1); Nanaimo, Holland (1888); Hosts: Pinus
spp., Abies spp., Pseudotsuga menziesii and
Thuja plicata (Barr 1971).

Subfamily Agrilinae
Tribe Agrilini
Agrilus politus (Say): Victoria, 5 to 20-V-26,
G. A. Hardy, willow, (PM) (11); Wellington,
anonymous (1906); Hosts: Salix spp. and Acer
spp. (Barr 1971).

This list increases to 23, the known number
of species of Buprestidae on Southern Van-
couver Island. The collecting data indicate that
buprestids are most common during the sum-
mer. This agrees with the observations of
Hardy (1927, 1942).

ACKNOWLEDGEMENTS

I thank Mr. N. Tonks of the Saanichton
Research Station, Mr. D. Evans of the Paci-
fic Forest Research Center, Drs. B. Ainscough
and R. Carcasson of the Provincial Museum
and Dr. R. Ring of the University of Victoria
for the loan and use of the collections entrusted
to their care.

REFERENCES
Anonymous. 1906. The British Columbia list. Coleoptera. Family Buprestidae. Bull. B.C. Ent.

Soc. .2:4.

Barr, W. F. 1971. Family Buprestidae. In Beetles of the Pacific Northwest, Part V, by M. H.
Hatch. Univ. of Wash. Publ. Biol. 16. p. 662.

Cannings, R. A. and K. M. Stuart, 1977. The Dragonflies of British Columbia. B.C. Prov. Mus.

Handbook no. 35; p. 256.

Evans, D. 1957. A revision of the genus Poecilonota in America north of Mexico (Coleoptera:
Buprestidae). Ann. Ent. Soc. Am. 50:21-37.

Hardy, G. A. 1927. Buprestidae of Vancouver Island. Prov. B.C. Mus. Nat. Hist. for 1926:

C32-C34.

. 1942. Notes on some wood-boring beetles of Saanich Vancouver Island, B.C. (Coleoptera,
Cerambycidae, Buprestidae) Proc. Ent. Soc. B.C. 39:9-13.

40 J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DEc. 31, 1978

Hatch. M. H. 1953. The Beetles of the Pacific Northwest, Part I, Introduction and Adephaga.

Univ. Wash. Publ. Biol. 16. p. 348.

Holland, W. J. 1888. Captures made while travelling from Winnipeg to Victoria, B.C. Can. Ent.

20: 89-92.

LeConte, J. L. 1869. List of Coleoptera collected in Vancouver’s Island by Henry and Joseph
Matthews, with descriptions of some new species. Ann. Mag. Nat. Hist. Ser. 4. 6:369-385.

Walker, F. 1866. List of Coleoptera. In Lord’s Naturalist in Vancouver Island and British Colum-

bia Vol. 2: 309-334.

EUTROMULA PARIANA (CLERCK)
(LEPIDOPTERA: CHOREUTIDAE), THE CORRECT NAME OF THE
APPLE-AND-THORN SKELETONIZER

JOHN B. HEPPNER

Department of Entomology
National Museum of Natural History
Smithsonian Institution, Washington, D.C. 20560

ABSTRACT
Nomenclatural problems are noted which make Eutromula pariana
(Clerck) the correct name of the apple-and-thorn skeletonizer. Previously
used generic names are distinct genera (Anthophila Haworth and Hemero-
phila Hubner, [1817]), synonyms (Simaethis Leach), or unavailable names
(““Hemerophila’”’ Hubner, 1806). The species is now placed. in the family
Choreutidae (Sesioidea) which has been separated from Glyphipterigidae

(Copromorphoidea).

The apple-and-thorn skeletonizer, Eutromula
pariana (Clerck), is an occasional pest of apple
trees, introduced from Europe this century.
It is now firmly established in apple growing
areas of the northeastern United States and
southeastern Canada, and in British Columbia,
going south to Oregon, Idaho, and Colorado.
The specific name of the species has been com-
bined with several generic names in the past,
mostly Anthophila, Simaethis, and Hemero-
phila. The latter generic association was most
recently affirmed by Danilevsky and Kuznet-
sov (1973) and noted by Doganlar (1977).

In a forthcoming revision of the North
American Choreutidae (Heppner, in prep.),
the name used for the species will be Eutro-
mula pariana, following the combination used
in a recent British checklist of Lepidoptera
(Bradley, 1972). Danilevsky and Kuznetsov
(1973), unfortunately, used an 1806 Hubner
generic name that is now unavailable for use
due to the rejection of Hiibner’s 1806 paper by

1. Glyphipterigidae is based on the original spelling of Glyphipterix as required by the Interna-
tional Code of Zoological Nomenclature, rather than the emendation Glyphipteryx (Gly-

phipterygidae).

the International Commission on Zoological
Nomenclature (Opinion 97, 1926). The next
available generic name is Eutromula Frolich,
1828, with EF. pariana as its type-species. The
available and valid Hemerophila Hubner,
[1817] (not Hubner, 1806), refers to a Neotropi-
cal genus. Simaethis Leach, 1815 is a junior
synonym of Anthophila Haworth, [1811], which
refers to a genus distinct from Eutromula.

Although there are dark and light forms of
E. pariana, both in the Nearctic and the
Palearctic, Doganlar (1977) correctly noted that
only one species is involved. A recent paper has
noted the reasons for the separation of gly-
phipterigid moths into two families. Glyphip-
terigidae! and Choreutidae (Heppner, 1977).
The two families actually are unrelated and
belong in different superfamilies based upon
morphological and biological features, thus,
Copromorphoidea and Sesioidea, respectively,
with Choreutidae being relatively closely relat-
ed to the specialized Sesiidae.

J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DEc. 31, 1978 4]

REFERENCES
Bradley, J. D. 1972. (Microlepidoptera parts). Part 2: Lepidoptera [in part]. In, Kloet and Hincks,
A check list of British insects. Second Edition (revised). Royal Ent. Soc. Lond., London.
153 pp.

Danilevsky, A. S., and V. I. Kuznetsov. 1973. (A review of the glyphipterygid moths of the genus
Hemerophila Hb. (Lepidoptera, Glyphipterygidae) of the fauna of the USSR.). Tr.
Vsesoyuz. Ent. Obshch. 56:8-17. [in Russian].

Doganlar, M. 1977. The systematic position of the apple-and-thorn skeletonizer. J. Ent. Soc. Br.
Columbia 74:26.

Heppner, J. B. 1977. The status of the Glyphipterigidae and a reassessment of relationships in
yponomeutoid families and ditrysian superfamilies. J. Lepid. Soc. 31:124-134.

Heppner, J. B. (in prep.). Sesioidea. Choreutidae. In, Dominick, et al, The moths of America north
of Mexico. Fasc. 8.4. Classey, London. (approx. 100 pp., 4 pls.).

Opinion 97. 1926. Did Hubner’s Tentamen, 1806, create monotypic genera? Smithson. Misc. Coll.
73: 19-30.

LARVAL TAXONOMY AND DISTRIBUTION OF
GERRIS PINGREENSIS AND G. INCOGNITUS
(HEMIPTERA: GERRIDAE) IN BRITISH COLUMBIA

J. R. SPENCE AND G. G. E. SCUDDER

Department of Zoology
University of British Columbia
Vancouver, B.C.

ABSTRACT

Diagnostic morphological characters are given for the five larval instars
of Gerris pingreensis and Gerris incognitus. The geographic ranges of the

two species are compared and discussed.

INTRODUCTION

Waterstriders (Gerris) are common inhabi-
tants of British Columbia’s inland waters. Ease
of observation and the common occurrence of
multispecies assemblages make these insects
attractive subjects for comparative ecological
study. A knowledge of species characteristics
and natural history are necessary prerequisites
for such work.

Scudder (1971) provided keys and descrip-
tions for the adults of British Columbia gerrids
and Scudder and Jamieson (1972) produced an
identification guide for the larvae of seven
species. At the time of these publications it
was not possible to separate the first three
instars of Gerris pingreensis D&H and Gerris
incognitus D&H. Furthermore, the characteris-
tics noted for separation of fourth and fifth
instars of these two species are inefficient
because of a typographical error missed in the
proof.

In this paper we provide diagnostic descrip-
tions for all larval instars of both species and
compare the geographic ranges of these two
species in British Columbia. Areas of sympatry
and allopatry are noted.

METHODS AND MATERIALS

During May 1976 and 1977 we established
laboratory cultures of G. pingeensis and G. in-
cognitus. Adult G. pingreensis were collected
from Westwick Lake in the Cariboo region
while G. incognitus were obtained from small
ponds in the University of British Columbia
Endowment Lands. All five larval instars of
both species were subsequently reared from
eggs laid by isolated adults. Details of the rear-
ing methods are given by Scudder and Jamie-
son (1972). Specimens of each larval instar
were preserved in 70% ethanol 1 or 2 days
after molting. Instar descriptions are based
upon study of these laboratory-reared speci-
mens. We have also checked the descriptions
against field material collected on the lower
mainland and in the central interior from loca-
tions where only one of the species is known to
occur.

RESULTS AND DISCUSSION
A. Larval Taxonomy
The keys and descriptions provided by
Scudder and Jamieson (1972) afford easy
separation of G. pingeensis and G. incognitus

42 J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DEc. 31, 1978

Figure 1. First Instar (a) G. pingreensis (b) G. incognitus.

from other gerrid species in the province. The
descriptions that follow can be used to separate
the five instars of these two species. Diagnostic
measurements provided by Scudder and Jamie-
son (1972) are additionally helpful for identify-
ing the fourth and fifth instars.

First and Second Instars

G. pingreensis: (Fig. la) with small but dis-
tinct sclerotized spots at the postero-lateral
corners of at least the 2nd and 3rd abdomi-
nal terga.

Figure 2. Third Instar (a) fully sclerotized G. pingreensis (b) teneral G. pingreensis (c) G. incognitus.

J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DEc. 31, 1978 43

Figure 3. Fourth Instar (a) G. pingreensis (b) G. incognitus.

G. incognitus: (Fig. 1b) without such markings G. incognitus: (Fig. 2c) sides of arrow-shaped

or with only an indistinct spot near the 2nd mark on mesonotum extending to the an-
abdominal tergum. tero-lateral corner as a narrow light band;
Third instar distinct light spot never delimited within

G. pingreensis: the mesonotum.

fully sclerotized specimens (Fig. 2a) arrow- Fourth and Fifth Instars
shaped mark on mesonotum not extending G. pingreensis: (Figs. 3a and 4a) with distinct

to the antero-lateral corner of the notum; arrow-shaped mark on mesonotum; isolated
distinct light spot in the antero-lateral cor- light spot in antero-lateral corner of mesono-
ner of the mesonotum. tum always present in 4th instar and usually
teneral specimens (Fig. 2b) sides of mesono- present in 5th instar.

tal arrow with broad light bands and ex- G. incognitus: (Figs. 3b and 4b) arrow-shaped
panded light area in the antero-lateral cor- mark on mesonotum poorly defined; lateral
ner. portion of arrow’s head not present or ex-

Figure 4. Fifth Instar (a) G. pingreensis (b) G. incognitus.

44 J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), Dec. 31, 1978

tending to the antero-lateral corner of the
mesonotum only as a very thin line which
is barely distinguishable from the surround-
ing sclerotization; 4th instar occasionally
with isolated light spot at the antero-lateral
corner of the mesonotum, such markings
never present in 5th instar.

B. Distribution

Locality records of these two species in
British Columbia are plotted in Figure 5. The
records are taken from Scudder (1977) and from
additional collections in the Chilcotin region
during the Spring and Summer of 1977.

The ranges of these two species are some-

what complementary in British Columbia.
Gerris incognitus is the dominant species of
the pair in the southern half of the province.
However it is not generally successful in the
parkland of the central interior even though
clear access seems possible from both east and
west. Gerris pingreensis is the only species of
the pair to be recorded from the northern
interior and occurs without G. incognitus on
the interior Chilcotin Plateau.

Although these two species are generally
allopatric in British Columbia, a broad zone of
overlap occurs in the central interior. This area
is one of the main suture zones in the province
where species from the prairies have establish-

Figure 5. Distribution of G. pingreensis (o) and G. incognitus (@ ) in British Columbia.

J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DEc. 31, 1978 45

ed contact with Cordilleran species. Remington
(1968) points out that significant biological
interactions often occur between similar species
in such suture zones.

The fact that G. pingreensis and G. incogni-
tus co-occur over such a broad area in the
central interior suggests either that these
species are not experiencing significant inter-
specific competition despite their pronounced
similarity or that competitive advantages are

shifting over space or fluctuating in time. We
shall discuss these possibilities in more detail
elsewhere.

ACKNOWLEDGEMENTS
This research was supported by a grant to
G. G. E. Scudder from the National Research
Council of Canada. We thank D. H. Spence
for her meticulous care of young waterstriders.

LITERATURE CITED
Remington, C. L. 1968. Suture zones of hybrid interaction between recently joined biotas. Evol.

Biol. 2: 321-428.

Scudder, G. G. E. 1977. An annotated checklist of the aquatic and semiaquatic Hemiptera
(Insecta) of British Columbia. Syesis 10: 31-38.

Scudder, G. G. E. 1971. The Gerridae (Hemiptera) of British Columbia. J. Entomol. Soc. Brit..

Columbia 68: 3-10.

Scudder, G. G. E. and G. S. Jamieson. 1972. The immature stages of Gerris (Hemiptera) in British
Columbia. J. Entomol. Soc. Brit. Columbia 69: 72-79.

THE APHIDS (HOMOPTERA:APHIDIDAE)
OF BRITISH COLUMBIA 5. NAME CHANGES!

CHO-KAICHAN ANDA. R. FORBES

Research Station, Agriculture Canada
Vancouver, British Columbia

ABSTRACT
Name changes in accordance with current usage in aphid taxonomy are

listed.

INTRODUCTION
An approach to a stable nomenclature for
aphids became possible with the recent publica-
tion of a “Survey of the World’s Aphids’’
(Eastop and Hille Ris Lambers 1976). We de-

1Contribution No. 416, Research Station, 6660 N.W. Marine
Drive, Vancouver, British Columbia, V6T 1X2.

cided to adopt that work as a standard for all
our aphid names. This has necessitated chang-
ing 72 names used in our previous lists (Forbes,
Frazer and MacCarthy 1973; Forbes, Frazer
and Chan 1974; Forbes and Chan 1976). All
of these changes are listed here. They are
arranged alphabetically by genus and species
of the names used previously.

LIST OF NAME CHANGES

Previous Name

Acyrthosiphon dirhodum (Walker)
Acyrthosiphon pisum spartii (Koch)
Allaphis verrucosa (Gillette)

Aphis corniella Hille Ris Lambers
Aphis sambucifoliae Fitch

Asiphum rosettei Maxson
Aspidaphis longicauda Richards
Aulacorthum clavicornis Richards
Aulacorthum dorsatum Richards
Aulacorthum scabrosum Richards
Bipersona torticauda Gillette
Brachycolus atriplicis (Linnaeus)
Cavariella umbellatarum (Koch)
Cepegillettea betulaefoliae Granovsky
Chaitophorus delicata Patch
Chaitophorus neglectus Hottes & Frison

Current Name
Metopolophium dirhodum (Walker)
Acyrthosiphon pisum (Harris)
Thripsaphis verrucosa Gillette
Aphis salicariae Koch
Aphis sambuci Linnaeus
Asiphum tremulae (Linnaeus)
Eoessigia longicauda (Richards)
Wahlgreniella nervata (Gillette)
Sitobion dorsatum (Richards)
Aulacorthum capilanoense Robinson
Bipersona ochrocentri (Cockerell)
Hayhurstia atriplicis (Linnaeus)
Cavariella aegopodii (Scopoli)
Calaphis betulaefoliae (Granovsky)
Chaitophorus stevensis Sanborn
Chaitophorus populifolii neglectus
Hottes & Frison

46 J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), Dec. 31, 1978

Cinara abieticola Cholodkovsky
Colopha ulmisacculi Patch
Dactynotus ambrosiae (Thomas)
Dactynotus cirsii (Linnaeus)
Dactynotus erigeronensis (Thomas)
Dactynotus nigrotuberculatus Olive
Dactynotus pseudambrosiae Olive
Dactynotus russellae Hille Ris Lambers
Dactynotus sonchi (Linnaeus)
Dactynotus taraxaci (Kaltenbach)
Euschizaphis palustris (Theobald)
Holcaphis frequens (Walker)
Holcaphis nodulus Richards
HAyadaphis erysimi (Kaltenbach)
Kakimia canadensis Robinson
Kakimia essigi (Gillette & Palmer)
Kakimia robinsoni Richards
Macrosiphum avenae (Fabricius)
Macrosiphum coweni (Hunter)

Macrosiphum fragariae (Walker)
Macrosiphum manitobensis Robinson
Macrosiphum nigromaculosum MacDougall
Macrosiphum ptericolens Patch
Macrosiphum rhamni Clarke
Macrosiphum salicicornii Richards
Macrosiphum yagasogae (Hottes)
Masonaphis crystleae (Smith & Knowlton)
Masonaphis davidsoni (Mason)
Masonaphis lambersi MacGillivray
Masonaphis magna Hille Ris Lambers
Masonaphis maxima (Mason)
Masonaphis morrisoni (Swain)
Masonaphis patriciae Robinson
Masonaphis pseudomorrisoni MacGillivray
Masonaphis richardsi MacGillivray
Masonaphis spiraeae MacGillivray
Masonaphis spiraecola (Patch)
Masonaphis wahnaga Hottes
Neoceruraphis viburnicola (Gillette)
Parathecabius gravicornis (Patch)
Parathecabius populimonilis (Riley)
Prociphilus alnifoliae alnifoliae (Williams)
Pterocomma bicolor bicolor (Oestlund)
Rhopalosiphum fitchii (Sanderson)
Roepkea bakeri (Cowen)

Roepkea crataegifoliae (Fitch)

Roepkea sclerosa Richards

Roepkea sensoriata (Gillette & Bragg)
Roepkea yohoensis (Bradley)

Sipha kurdjumovi Mordvilko

Sitomyzus columbiae Richards
Sitomyzus humboldti (Essig)

Stagona xylostei (de Geer)

Thelaxes albipes Richards

Trichocallis cyperi (Walker)
Tuberculoides annulatus (Hartig)

Cinara confinis (Koch)
Tetraneura ulmi (Linnaeus)
Uroleucon ambrosiae (Thomas)
Uroleucon cirsii (Linnaeus)
Uroleucon erigeronensis (Thomas)
Uroleucon nigrotuberculatum (Olive)
Uroleucon pseudambrosiae (Olive)
Uroleucon russellae (Hille Ris Lambers)
Uroleucon sonchi (Linnaeus)
Uroleucon taraxaci (Kaltenbach)
Schizaphis palustris (Theobald)
Diuraphis frequens (Walker)
Diuraphis nodulus (Richards)
Lipaphis erysimi (Kaltenbach)
Delphiniobium canadense (Robinson)
Kakimia aquilegiae (Essig)
Kakimia wahinkae (Hottes)
Sitobion avenae (Fabricius)
Obtusicauda artemisiae (Cowen ex Gillette &
Baker)
Sitobion fragariae (Walker)
Sitobion manitobense (Robinson)
Eomacrosiphon nigromaculosum (MacDougall)
Sitobion ptericolens (Patch)
Sitobion rhamni (Clarke)
Sitobion salicicornii (Richards)
Sitobion insulare yagasogae (Hottes)
Illinoia crystleae (Smith & Knowlton)
Illinoia davidsoni (Mason)
Illinoia lambersi (MacGillivray)
Illinoia magna (Hille Ris Lambers)
Illinoia maxima (Mason)
Illinoia morrisoni (Swain)
Illinoia patriciae (Robinson)
Illinoia morrisoni (Swain)
Illinoia richardsi (MacGillivray )
Illinoia spiraeae (MacGillivray)
Illinoia spiraecola (Patch)
Illinoia wahnaga (Hottes)
Ceruraphis viburnicola (Gillette)
Thecabius gravicornis (Patch)
Thecabius populimonilis (Riley)
Prociphilus alnifoliae (Williams)
Pterocomma bicolor (Oestlund)
Rhopalosiphum insertum (Walker)
Nearctaphis bakeri (Cowen)
Nearctaphis crataegifoliae (Fitch)
Nearctaphis sclerosa (Richards)
Nearctaphis sensoriata (Gillette & Bragg)
Nearctaphis yohoensis Bradley
Sipha elegans del Guercio
Utamphorophora humboldti (Essig)
Utamphorophora hum boldti (Essig)
Prociphilus xylostei (de Geer)
Thelaxes californica (Davidson)
Thripsaphis cyperi (Walker)
Tuberculatus annulatus (Hartig)

REFERENCES
Eastop, V. F., and D. Hille Ris Lambers. 1976. Survey of the world’s aphids. Dr. W. Junk b.v.,

Publishers, The Hague.

Forbes, A. R., and Cho-Kai Chan. 1976. The aphids (Homoptera: Aphididae) of British Columbia.
4. Further additions and corrections. J. ent. Soc. Brit. Columbia 73:57-63.

J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DEc. 31, 1978 47

Forbes, A. R., B. D. Frazer and Cho-Kai Chan. 1974. The aphids (Homoptera: Aphididae) of British
Columbia. 3. Additions and corrections. J. ent. Soc. Brit. Columbia 71:43-49.

Forbes, A. R., B. D. Frazer and H. R. MacCarthy. 1973. The aphids (Homoptera: Aphididae) of
British Columbia. 1. A basic taxonomic list. J. ent. Soc. Brit. Columbia 70:43-57.

THE APHIDS (HOMOPTERA: APHIDIDAE)
OF BRITISH COLUMBIA
6. FURTHER ADDITIONS!

A. R. FORBES AND CHO-KAI CHAN

Research Station, Agriculture Canada
Vancouver, British Columbia

ABSTRACT
Twenty-four species of aphids and new host records are added to the
taxonomic list of the aphids of British Columbia.

INTRODUCTION

Three previous lists of the aphids of British
Columbia (Forbes, Frazer and MacCarthy
1973; Forbes, Fraser and Chan 1974; Forbes
and Chan 1976) recorded 285 species, but with
the deletion of 7 synonyms? (Eastop and Hille
Ris Lambers 1976) the number becomes 278.
This includes aphids collected from 421 hosts?
or in traps and comprises 792 aphid-host plant
associations’.

The present list adds 24 species of aphids
(indicated with an asterisk in the list) and 172
aphid-host plant associations to the previous
lists. Ninety-three of the new aphid-host plant
associations are plant species not in the pre-
vious lists. The additions bring the number of
known aphid species in British Columbia to

‘Contribution No. 417, Research Station, 6660 N.W. Marine
Drive, Vancouver, British Columbia, V6T 1X2.

302. Aphids have now been collected from 514
different host plants and the total number of
aphid-host plant associations is 964.

As in the previous lists, the aphids are
arranged alphabetically by species. All names
are in accordance with Eastop and Hille Ris
Lambers (1976). The location of each collection
site can be determined from Table 1 or from
tables of localities in the previous paper. The
reference points are the same as those shown
on the map which accompanies the basic list.

*Aulacorthum clavicornis Richards,

Aulacorthum scabrosum Richards,

Cavariella umbellatarum (Koch),

Masonaphis pseudomorrisoni MacGillivray,

Rhopalosiphum fitchii (Sanderson),

Sitomyzus columbiae Richards,

Thelaxes albipes Richards.

’Quercus borealis and Philadelphus lewisii var. gordonianus
of earlier lists being deleted as synonyms, based on Hortus
Third.

TABLE 1. Localities where aphids were collected, with airline distances from reference points.

3 Reference
Locality Point
Botanie Valley Kamloops
Colwood Victoria
Harrison Lake Vancouver
Naramata Kelowna
Peachland Kelowna
Port Coquitlam Vancouver
Port Washington Victoria
Silver Lake Kelowna
Tulameen Kelowna
White Rock Vancouver
Yarrow Vancouver

Di Distance

at km mi
SW 94 59
W 16 10
NE 114 71
S ow 20
SW 22 14
E oF: 23
N 45 28
W 53 33
SW 102 64
SE 37 23
SE 92 58

48 J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DEc. 31, 1978

LIST OF SPECIES

*ADIANTI (Oestlund), SITOBION
Athyrium filix-femina: Vancouver, May 2/58.
Polystichum munitum: North Vancouver,
May 17/73; Vancouver, Apr 27/63, May
2/58, May 19/58; Vancouver (UBC), Jan
23/76, Feb 17/76, Mar 29/74, Apr 22/74,
Apr 30/75, May 21/74, May 23/75.

*AFFINIS (Kaltenbach), THECABIUS
Ranunculus occidentalis: Vancouver,
15/76, Dec 31/76.

AGATHONICA Hottes, AMPHOROPHORA
Rubus idaeus: Abbotsford, Aug 2/74; North
Vancouver, Jun 18/74; Vancouver, Jun
22/75; Yarrow, Aug 2/74.

ALNI (de Geer), PTEROCALLIS
Alnus rubra: Vancouver (UBC), May 12/76,
May 18/76.
Rosa sp: Pemberton, Jul 16/76.

ALNIFOLIAE (Williams), PROCIPHILUS
Amelanchier alnifolia: Peachland, May 21/76.

AQUILEGIAE (Essig), KAKIMIA
Aquilegia alpina: Vancouver (UBC),
28/76.

Aquilegia formosa: Vancouver (UBC), Aug
13/76.

ASCALONICUS Doncaster, MYZUS
Anemone pulsatilla: Vancouver (UBC), Aug
13/76.

Bellis perennis: Vancouver (UBC), Feb 8/77,
Jul 14/76.

Cerastium fontanum ssp triviale: Vancouver
(UBC), Dec 15/76.

Claytonia sibirica var _ sibirica:
(UBC), Feb 8/77.

Meconopsis betonicifolia: Vancouver (UBC),
Jun 28/76.

Myosotis arvensis: Vancouver, May 17/76.
Phlox paniculata: Vancouver (UBC), May
1/58.
Ranunculus
31/76.
Stellaria media: Vancouver (UBC), Jul 10/75.
Viburnum x bodnantense: Vancouver (UBC),
May 23/76.

* A UDENI MacDougall, MACROSIPHUM
Nuphar lutea ssp polysepala: Merritt, /24.
(MacDougall 1926).

BERBERIDIS (Kaltenbach), LIOSOMAPHIS
Berberis verruculosa: Vancouver (UBC),
May 20/76.

BICOLOR (Oestlund), PTEROCOMMA
Populus nigra ‘Italica’: Vancouver (UBC),
May 3/74.

*BISENSORIATUM MacDougall,

MACROSIPHUM
Ribes lacustre: Boundary Bay, Jul /24,
(MacDougall 1926), Aug /24, (MacDougall
1926).

BRASSICAE (Linnaeus), BREVICORYNE

Dec

Jun

Vancouver

occidentalis: Vancouver, Dec

Brassica pekinensis: Richmond, Aug 20/76.
Brassica rapa var lorifolia: Richmond, Aug
20/76.

CALIFORNICA (Davidson), THELAXES
Quercus garryana: Colwood, May 9/76.

CALIFORNICUM (Clarke), MACROSIPHUM
Salix scouleriana: Vancouver (UBC), Jun

13/75.

*CALLIPTERUS (Hartig),
CALLIPTERINELLA

Betula pendula ‘Dalecarlica’: Vancouver,
May 26/76.

CAPILANOENSE Robinson,
AULACORTHUM

Polystichum munitum: Vancouver, May
2/58.

Rubus spectabilis: Vancouver (UBC), Apr
30/76, May 14/76, Jul 14/76.

CARAGANAE (Cholodkovsky),

ACYRTHOSIPHON

Caragana arborescens: Vancouver (UBC),
Oct 6/75.

Colutea melanocalyx: Vancouver (UBC),
Aug 4/76.

CARDUI (Linnaeus), BRACHYCAUDUS
Cirsium arvense: Summerland, Jul 3/76.
Rhus sp: Vancouver (UBC), Jun 1/76.

*CARICIS (Glendenning), SITOBION
Carex sp: Agassiz, Aug /26, (Glendenning
1926).

CERASI (Fabricius), MYZUS
Galium mollugo: Vancouver, Jul 21/76.
Liriodendron tulipifera: Vancouver (UBC),
Oct. 6/75.
Prunus emarginata: Vancouver (UBC), Jun
1/715.

Prunus ‘Royal Anne’: Vancouver (UBC),
Sep 23/76.
Prunus serrulata ‘Kwanzan’: Vancouver

(UBC), Jun 24/75.
CERASIFOLIAE (Fitch),
RHOPALOSIPHUM
Prunus virginiana: Lumby, Jul 14/76; Sum-
merland, Jun 14/76.
CIRCUMFLEXUM (Buckton),
AULACORTHUM
Papaver orientale: Vancouver, Jul 20/58.
CIRSII (Linnaeus), VJROLEUCON
Cirsium arvense: Summerland, Jul 3/76.
*CITRICOLA van der Goot, APHIS

Calycanthus fertilis: Vancouver (UBC),
Jul 20/76.
Stranvaesia davidiana: Vancouver (UBC),
Jul 30/76.

COLUMBIAE Richards, TUBERCULATUS
Quercus garryana: Colwood, May 9/76.

CORNI (Fabricius), ANOECIA
Cornus alba ‘Sibirica’: Vancouver (UBC),
Sep 22/75.

J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DEc. 31, 1978 49

Cornus nuttallii: Vancouver (UBC), Oct 6/75.
Cornus purpusii: Vancouver (UBC), Sep
22/75, Sep 25/75.
Cornus sanguinea:
6/75.

Cornus sericea: Peachland, May 21/75; Van-
couver (UBC), Nov 7/75.

COWEN I (Cockerell), TAMALIA
Arctostaphylos uva-ursi: Vancouver (UBC),
Jun 24/76, Jul 18/76, Aug 25/76, Sept 9/76.

*CRACCAE Linnaeus, APHIS
Moericke yellow pan water trap: Penticton,
Jun 30/75.

CURVIPES (Patch), CINARA
Abies grandis: Vancouver (UBC), May 18/76.

DIRHODUM (Walker), METOPOLOPHIUM
Rosa sp: Pemberton, Jul 16/76.

DORSATUM (Richards), SITOBION
Gaultheria shallon: Vancouver (UBC), Jul
27/76.

EPILOBII Kaltenbach, APHIS
Epilobium ciliatum: Vancouver, May 25/76.
ERIOPHORI (Walker), CERURAPHIS
Viburnum opulus ssp trilobum: Vancouver
(UBC), Oct 6/75.
Viburnum x bodnantense: Vancouver (UBC),
Jun 1/76.
ERYSIMI (Kaltenbach), LIPAPHIS
Brassica rapa ssp campestris: Abbotsford,
Jul 5/76; Vancouver, Jul 27/76.

EUPHORBIAE (Thomas), MACROSIPHUM

Vancouver (UBC), Oct

Balsamorhiza sagittata: Penticton, May
23/76.

Brassica rapa ssp campestris: Vancouver,
Jul 27/76.

Callistephus chinensis: Vancouver, Jun
16/76.

Cornus sericea: Vancouver (UBC), Nov 7/75.
Daphne cneorum: Vancouver (UBC), May
19/76, May 25/76.
Daphne laureola:
19/76, Jun 28/76.

Vancouver (UBC), May

Hibiscus rosa-sinensis: Vancouver (CDA),
Aug 17/76.
Hieracium aurantiacum: Vancouver (UBC),
Aug 23/76.

Hosta sieboldiana: Vancouver (UBC), Aug
16/76.
Incarvillea mairei var grandiflora: Vancouver
(UBC), Jun 28/76.

Jacaranda acutifolia: Port Coquitlam, Aug
22/76.

Liriodendron tulipifera: Vancouver (UBC),
Jul 22/75, Aug 9/76, Oct 6/75.

Myosotis arvensis: Vancouver, May 25/76.

Nothofagus antarctica: Vancouver (UBC),
Jun 11/76.

Oemleria cerasiformis: Vancouver, Apr
217/13.

Photinia x fraseri: Vancouver (UBC), Jul
29/76.

Rubus spectabilis: Vancouver (UBC), May
14/76.

Solanum tuberosum: Quesnel, Jul 21/76.
Symphoricarpos albus: Vancouver, Jul 21/76.
Yucca filamentosa: Vancouver, Aug 15/74.

FABAE Scopoli APHIS
Arctostaphylos uva-ursi: Vancouver (UBC),
Sep 9/76, Sep 23/75.
Beta vulgaris: Brentwood, Jul 5/59; Ladner,
Aug 27/58.
Calendula officinalis: Vancouver, Aug 12/76.
Crocosmia x crocosmiiflora: Vancouver, Aug
12/16.
Ficus carica: Vancouver (UBC), Aug 14/75.
Galium mollugo: Vancouver, Jul 21/76.
Holodiscus discolor: Vancouver (UBC), Oct
3/75.
Hosta undulata: Vancouver, Aug 19/76.
Liriodendron tulipifera: Vancouver (UBC),
Sep 11/75, Oct 6/75.
Lunaria annua: Vancouver, Aug 18/76.
Lysimachia punctata: Vancouver, Jul 21/76.
Phlox paniculata: Vancouver, Aug 12/76.
Physalis alkekengi: Vancouver, Aug 12/76.
Rhus sp: Vancouver (UBC), Jun 1/76.
Tropaeolum majus: Vancouver, Aug 18/76.
Viburnum opulus ssp trilobum: Vancouver
(UBC), Oct 6/75.
Yucca filamentosa: Vancouver, Aug 1/74,
Aug 10/74, Aug 15/74.

FAGI (Linnaeus), PHYLLAPHIS
Fagus sylvatica ‘Atropunicea’: Vancouver,
Jun 1/76.

FARINOSA Gmelin, APHIS
Salix scouleriana: Vancouver (UBC), Jun
137 75;

FIMBRIATA Richards, FIMBRIAPHIS
Liriodendron tulipifera: Vancouver (UBC),
Aug 9/76.

*FLAVA Mordvilko, CALAPHIS
Betula sp: Burnaby, Jul 14/63.

*FOENICULI (Passerini), HYADAPHIS
Lonicera ciliosa: Port Washington, Jun 8/76.

FORNACULA Hottes, CINARA
Picea sp: Richmond, Jul 4/76.

FRAGAEFOLII (Cockerell),
CHAETOSIPHON
Rosa sp: Pemberton, Jul 16/76.

FRAGARIAE (Walker), SITOBION
Cortaderia selloana: Vancouver, Jul 21/76.
Rubus discolor: Vancouver (UBC), Jul 25/75.
Grass: Vancouver (UBC), Jun 22/76.

*FUSCICORNIS MacDougall,
MACROSIPHUM
Epilobium angustifolium: Merritt, Jun 29/24,
(MacDougall 1926); Vancouver, Aug 24/24,
(MacDougall 1926).
GALEOPSIDIS (Kaltenbach),
CRYPTOMYZUS
Ribes sativum: Quesnel, Jul 21/76.

50 J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DEc. 31, 1978

GENTNERI (Mason), FIMBRIAPHIS
Amelanchier laevis: Vancouver (UBC), May
16/75,.Oct: 3/75.

Amelanchier ovalis: Vancouver (UBC), Jun
28/76, Oct. 10/75.

Crataegus monogyna: Vancouver, May 26/76.
Mespilus germanica: Vancouver (UBC), May
28/75.

HEDERAE Kaltenbach, APHIS
Hedera helix: Saanich, May 9/76; Vancouver
(UBC), Apr 29/76.

HELIANTHI Monell, APHIS
Cornus sericea: Peachland, May 21/76.

HELICHRYSI (Kaltenbach),
BRACHYCAUDUS
Chrysanthemum x morifolium: Vancouver,
Jul 21/76.
Prunus cerasifera ‘Atropurpurea’: Vancouver
(UBC), Jun 26/75.
Prunus domestica: Lumby, Jul 4/76; Pember-
ton, Jul 16/76; Summerland, Jun 10/76.
*HELVETICA Hille Ris Lambers,
BETULAPHIS
Betula sp: Vancouver, Oct 3/60.
HIPPOPHAES (Walker), CAPITOPHORUS
Polygonum lapathifolium: Vancouver (UBC),
Aug 18/75.
HUMBOLDTI (Essig),
UTAMPHOROPHORA
Physocarpus capitatus:
24715:
Physocarpus malvaceus: Vancouver (UBC),
Nov 4/75.
HUMULI (Schrank), PHORODON
Prunus domestica: Lumby, Jul 4/76.

INSERTUM (Walker), RHOPALOSIPHUM

Silver Lake, Oct

Chaenomeles japonica: Vancouver (UBC),
Oct 6/75.
Liriodendron tulipifera: Vancouver (UBC),
Oct 6/75.

Malus ioensis: Vancouver (UBC), Apr 27/76,
May 4/76, Oct 7/75.

Mespilus germanica: Vancouver (UBC),
May 28/75, Oct 6/75.

*JUNIPERI (de Geer), CINARA
Juniperus squamata ‘Meyeri’: Vancouver
(UBC), Aug 4/76, Sep 22/75.

LAMBERSI (MacGillivray), ILLINOIA
Daboecia cantabrica: Vancouver (UBC),
Sep 23/75.

Daboecia cantabrica ‘Alba’: Vancouver
(UBC), Sep 23/75.
Daboecia cantabrica ‘Atropurpurea’: Van-

couver (UBC), Jun 28/76.

Daboecia cantabrica ‘Praegerae’: Vancouver
(UBC), Jun 28/76.

Rhododendron ‘Elizabeth’: Vancouver (UBC),
Mar 29/76, Apr 26/76, Jun 16/76.
Rhododendron molle: Vancouver
Jun 30/76.

(UBC),

*LIRIODENDRI (Monell), ILLINOIA
Liriodendron tulipifera: Vancouver (UBC),
Aug 9/76.

LONGICAUDA (Richards), EOESSIGIA
Spiraea douglasii: Vancouver (UBC), Jul
27/76, Nov 7/75.

MACROSIPHUM (Wilson),

ACYRTHOSIPHON
Amelanchier laevis: Vancouver (UBC), Oct
3/75.

MILLEFOLII (de Geer),

MACROSIPHONIELLA
Achillea millefolium: Vancouver (UBC), Sep
23/7 15:

MORRISONI (Swain), ILLINOIA

Chamaecyparis _lawsoniana: Vancouver
(UBC), Sep 19/75.

xCupressocyparis leylandii: Vancouver
(UBC), Jun 10/75, Aug 29/75.

Juniperus squamata ‘Meyeri’: Vancouver

(UBC), Aug 4/76, Sept 22/75, Oct 3/75, Nov
4/75.

NASTURTII Kaltenbach, APHIS
Moericke yellow pan water trap: Naramata,
Oct 14/75; Penticton, Oct 14/75.

NEPHRELEPIDIS Davis, IDIOPTERUS
Saintpaulia ionantha: Vancouver, Apr 22/76.

NERVATA (Gillette), WAHLGRENIELLA
Arbutus menziesii: Vancouver (UBC), Jan
20/76, Sep 23/76, Nov 12/75, Dec 30/75.
Hypericum patulum ‘Hidcote’: Vancouver
(UBC), Jul 20/76.

NIGROMACULOSUM (MacDougall),

EOMACROSIPHON
Rosa nutkana: Botanie Valley, Jun 28/24,
(MacDougall 1926); Merritt, Jul 10/24, (Mac-
Dougall 1926).

NODULUS (Richards), DIURAPHIS
Moericke yellow pan water trap: Naramata,
Oct 14/75.

NYMPHAEAE (Linnaeus),

RHOPALOSIPHUM
Chaenomeles japonica:
Oct 6/75.

*OCCIDENTALIS Hille Ris Lambers &

Hottes, BOERNERINA
Moericke yellow pan water trap: Penticton,
Jun 23/75.

ORNATUS Laing, MYZUS
Alstroemeria aurantiaca: Vancouver (UBC),

Vancouver (UBC),

Sep 20/76.

Arabis caucasica: Vancouver (UBC), Jun
28/76.

Begonia cucullata var hookeri: Vancouver,
May 3/76.

Galium mollugo: Vancouver, Jul 21/76.
Gardenia jasminoides: Vancouver, Jan 3/77.

Halesia carolina: Vancouver (UBC), Jul
10/75.
Hypericum patulum ‘Hidcote’: Vancouver

J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DEc. 31, 1978 ay

(UBC), Jul 20/76.

Impatiens sp: Vancouver, Jun 2/76.
Myosotis arvensis: Vancouver, May 17/76,
May 25/76.

Nepeta cataria: Vancouver (UBC), Jun 28/76.
Philodendron hastatum: Vancouver, Feb
22/76.

Rosmarinus officinalis: Vancouver, Feb 9/77.
Thymus pseudolanuginosus: Vancouver
(UBC), Sep 20/76.

Viburnum x bodnantense: Vancouver (UBC),
Jun 1/76.

OSMARONIAE (Wilson), MACROSIPHUM

Oemleria cerasiformis: Vancouver (UBC),
Apr 22/76, May 30/75.

*PAPILLATA Theobald, JACKSONIA
Grass: Vancouver, Dec 15/76.

PARVIFLORI Hill, AMPHOROPHORA
Rubus ursinus: North Vancouver, Jun 18/74.

PATRICIAE (Robinson), ILLINOIA
Tsuga heterophylla: Vancouver (UBC), Jul
23/75, Aug 15/75.

PERSICAE (Sulzer), MYZUS
Aralia elata: Vancouver (UBC), Aug 25/76.
Beta vulgaris: Brentwood, Jul 5/59; Ladner,
Aug 27/58.
Buddleia davidii:
19/76.
Capsicum sp: Vancouver, Feb 22/76.
Epidendrum ibaguense: Vancouver (UBC),
Sep 22/76.
Hibiscus rosa-sinensis:
Aug 17/76, Sep 3/76.
Meconopsis paniculata:
Jun 28/76.
Physalis alkekengi: Vancouver, Aug 12/76.
Silene alba ssp alba: Vancouver (UBC),
Jun 3/76.
Trientalis latifolia: Vancouver (UBC), Jun
2/ 16:
Yucca filamentosa: Vancouver, Aug 15/74.

PISUM (Harris), ACYRTHOSIPHON
Medicago sativa: Summerland, Jul 3/76.
Melilotus alba: Vancouver (UBC), Aug 19/76.
Pisum sativum var arvense: Sumas, Jun
26/59; Vancouver, Jul 13/64.

Vicia sativa var angustifolia: Saanich, May
9/76. |

PLANTAGINEA (Passerini), DYSAPHIS
Malus ioensis: Vancouver (UBC), Apr 27/76,
May 4/76, Oct 7/75.

*POLEMONII (Gillette & Palmer), KAKIMIA
Moericke yellow pan water trap: Summer-
land, Jun 30/75.

POMI de Geer, APHIS
Crataegus monogyna: Vancouver, May 26/76.
Photinia x fraseri: Vancouver (UBC), Jul
29/76.

*POPULICAULIS Fitch, PEMPHIGUS
Populus trichocarpa: Vancouver (UBC), May

Vancouver (UBC), May

Vancouver (CDA),

Vancouver (UBC),

27/76, Jun 7/76, Jul 5/76; White Rock, May
22/76.

POPULIVENAE Fitch, PEMPHIGUS
Populus trichocarpa: Peachland, May 21/76;
Vancouver (UBC), Jun 7/76.

PRUNI (Geoffroy), HYALOPTERUS
Cortaderia selloana: Vancouver, Jul 21/76.
Liriodendron tulipifera: Vancouver (UBC),
Aug 9/76.

Prunus domestica: Lumby, Jul 4/76; Pember-
ton, Jul 16/76; Summerland, Jun 10/76,
Jul 37 16.

PRUNI Wilson & Davis, ASIPHONAPHIS
Prunus virginiana: Summerland, Jun 14/76.

*PTERIDIS (Wilson), SITOBION

Pteridium aquilinum: Vancouver (UBC),
Jul 23/74.

PUNCTIPENNIS (Zetterstedt),
EUCERAPHIS

Betula pendula ‘Dalecarlica’: Vancouver,
May 26/76.

Betula sp: Burnaby, Jul 14/63.
*PYRIFOLIAE MacDougall,
MACROSIPHUM

Sorbus sitchensis ssp grayi: Merritt, May

27/74, (MacDougall 1926); Tulameen, Jun

15/24, (MacDougall 1926).

*RARA Mordvilko, TRAMA
Moericke yellow pan water trap: Vancouver
(UBC), Aug 1/76.

RHAMNI (Clarke), SITOBION
Rhamnus purshiana: Vancouver (UBC), Apr
U7 (on OCU.3/ 15:

RIEHMI (Borner), THERIOAPHIS

Melilotus alba: Vancouver (UBC), Aug 19/76.
ROBINIAE (Gillette), APPENDISETA

Sophora japonica: Vancouver (UBC), Aug

4/76.

ROSAE (Linnaeus), MACROSIPHUM

Ilex aquifolium: Richmond, Jul 4/76.

Rosa sp: North Vancouver, Jun 18/74.
RUBITOXICA Knowlton, AMPHOROPHORA
Rubus ursinus: Vancouver (UBC), Jul 26/76.

RUMEXICOLENS (Patch),
BRACHYCAUDUS

Rumex acetosella: Vancouver (UBC), May

ZA/ AG:

SALICARIAE Koch, APHIS

Cornus alba ‘Argenteo-marginata’:

couver (UBC), Jun 3/75.

Cornus mas: Vancouver (UBC), Sep 22/75.

Cornus nuttallii: Vancouver (UBC), Oct 6/75.

Cornus purpusii: Vancouver (UBC), Sep

22/75, Sep 25/75.

Cornus sanguinea:

6/75, Nov 4/75.

SEDI Kaltenbach, APHIS
Sedum sp: Vancouver, Jul 7/76.

*SITCHENSIS Glendenning, EUCERAPHIS

Van-

Vancouver (UBC), Oct

52 J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), Dec. 31, 1978

Alnus viridis ssp sinuata: Harrison Lake,
May /26, (Glendenning 1926).

SOLANI (Kaltenbach), AULACORTHUM
Aeschynanthus radicans: Vancouver (CDA),
May 6/76.

Androsace sarmentosa:
May 6/76.

Aquilegia sp: Vancouver, May 11/76.
Chrysanthemum x morifolium: Vancouver,
Jul 21/76.

Digitalis purpurea: Vancouver, Jun 21/76;
Vancouver (UBC), Feb 8/77.
Hibiscus calyphyllus: Vancouver
Jul 26/76, Sep 16/76.

Hosta sieboldiana: Vancouver (UBC), Aug
16/76.

Incarvillea mairei var grandiflora: Vancouver
(UBC), Jun 28/76.

Lilium x hollandicum: Vancouver (UBC),
Aug 13/76.

Lilium szovitsianum:
Aug 13/76.
Lysimachia punctata: Vancouver, Jul 21/76.
Meconopsis betonicifolia: Vancouver (UBC),
Jun 28/76.

Meconopsis paniculata:
Jun 28/76.

Myosotis arvensis: Vancouver, May 25/76.
Nepeta cataria: Vancouver (UBC), May 6/76.
Nephrolepis exaltata ‘Bostoniensis’: Van-
couver (CDA), Feb 9/77.

Papaver orientale: Vancouver, Jul 20/58.
Primula auricula: Vancouver (UBC), May
6/76.

Primula denticulata: Vancouver (UBC), May
6/76.

Primula veris: Vancouver (UBC), May 6/76.

Vancouver (UBC),

(CDA),

Vancouver (UBC),

Vancouver (UBC),

Primula vialii: Vancouver (UBC), Jun 28/76.

Trientalis latifolia: Vancouver (UBC), Jun
2716.

Trifolium pratense: Vancouver (CDA), Mar
3/76, (In Greenhouse).
Triteleia hyacinthina:
Jun 28/76.

Viburnum x bodnantense: Vancouver (UBC),
May 18/76.

Vicia sativa var angustifolia: Saanich, May
9/76.

Vinca major: Saanich, May 9/76.

SPIRAEAE (MacGillivray), ILLINOIA
Spiraea x arguta: Vancouver (UBC), Jun
19/75. i
Spiraea x bumalda: Vancouver (UBC), Jun
19/75.

SPYROTHECAE Passerini, PEMPHIGUS
Populus nigra ‘Italica’: Vancouver (UBC),
May 3/74.

*SUBVIRIDE MacDougall, MACROSIPHUM
Aster alpinus: Botanie Valley, Jun 27/25,
(MacDougall 1926), Aug 2/25, (MacDougall
1926).

TANACETARIA (Kaltenbach),

MACROSIPHONIELLA
Tanacetum vulgare: Cloverdale, Aug 18/76.

TARAXACI (Kaltenbach), VROLEUCON
Taraxacum officinale: Vancouver, Jun 19/76.

TESTUDINACEUS (Fernie), PERIPHYLLUS
Acer rubrum: Vancouver (UBC), Apr 30/74.

*TRIFOLII (Monell), THERIOAPHIS
Moericke yellow pan water trap: Penticton,
Sep 9/75; Summerland, Oct 14/75.

Vancouver (UBC),

*Aphid species not in the previous lists.

REFERENCES
Eastop, V. F., and D. Hille Ris Lambers. 1976. Survey of the world’s aphids. Dr. W. Junk b.v.,

Publishers, The Hague.

Forbes, A. R., and Cho-Kai Chan. 1976. The aphids (Homoptera: Aphididae) of British Columbia.
4. Further additions and corrections. J. ent. Soc. Brit. Columbia 73:57-63.

Forbes, A. R., B. D. Frazer and Cho-Kai Chan. 1974. The aphids (Homoptera: Aphididae) of
British Columbia. 3. Additions and corrections. J. ent. Soc. Brit. Columbia 71:43-49.
Forbes, A. R., B. D. Frazer and H. R. MacCarthy. 1973. The aphids (Homoptera: Aphididae) of

British Columbia. 1. A basic taxonomic list. J. ent. Soc. Brit. Columbia 70:43-57.

J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DrEc. 31, 1978

53

THE APHIDS (HOMOPTERA:APHIDIDAE)
OF BRITISH COLUMBIA
7. A REVISED HOST PLANT CATALOGUE!

A. R. FORBES AND CHO-KAI CHAN

Research Station, Agriculture Canada
Vancouver, British Columbia

ABSTRACT
A host plant catalogue is presented for 302 species of aphids collected

in British Columbia.

INTRODUCTION

All of the aphids recorded from British
Columbia (Forbes, Frazer and MacCarthy
1973; Forbes, Frazer and Chan 1974; Forbes
and Chan 1976, 1978) that were actually
colonizing on hosts are included in this revised
host plant catalogue. This catalogue super-
sedes a previous one (Forbes and Fraser 1973).

The scheme of plant classification followed
is that of Cronquist (1968, 1971). Names of
native plants are based on Crabbe, Jermy and
Mikel (1975); Hitchcock and Cronquist (1973);
Schofield (1969); and Taylor and MacBryde
(1977). Names of cultivated plants are based on
Hortus Third: A Concise Dictionary of Plants
Cultivated in the United States and Canada.
Plants are listed alphabetically by family,
genus, species and variety within each class.
Common names of the plants are included.

Aphids are listed alphabetically by genus
and species. The names are in conformity with
Eastop and Hille Ris Lambers (1976).

The compilation of this catalogue was
facilitated by computer (Raworth and Frazer
1976).

CATALOGUE OF HOST PLANTS
CL. BRYOPSIDA (MOSSES)
F. Polytrichaceae
Pogonatum urnigerum
Myzodium modestum
Polytrichum commune Common Haircap Moss
Myzodium modestum
Polytrichum juniperinum
Juniper Haircap Moss
Myzodium modestum

Urn Bearded Moss

CL. POLYPODIOPSIDA (FERNS)
F. Aspleniaceae
Athyrium filix-femina
Sitobion adianti
Polystichum munitum
Aulacorthum capilanoense
Sitobion adianti
Sitobion ptericolens
F. Davalliaceae
Nephrolepis exaltata ‘Bostoniensis’
Boston Fern

‘Contribution No. 418, Research Station, 6660 N.W. Marine
Drive, Vancouver, British Columbia, V6T 1X2.

Common Lady Fern

Sword Fern

Aulacorthum solani
F. Dennstaedtiaceae
Pteridium aquilinum
Sitobion pteridis
F. Polypodiaceae
Unknown sp
Idiopterus nephrelepidis

Bracken Fern

CL. PINOPSIDA (CONIFERS)
F. Cupressaceae
Chamaecyparis lawsoniana
Lawson Falsecypress
Illinoia morrisoni
Chamaecyparis pisifera Sawara Falsecypress
Illinoia morrisoni
Chamaecyparis pisifera ‘Boulevard’
Boulevard Sawara Falsecypress
Illinoia morrisoni
Chamaecyparis pisifera ‘Filifera’
Thread Sawara Falsecypress
Illinoia morrisoni
Chamaecyparis pisifera ‘Plumosa’
Plume Sawara Falsecypress
Illinoia morrisoni
Chamaecyparis pisifera ‘Squarrosa’
Moss Sawara Falsecypress
Illinoia morrisoni
xCupressocyparis leylandii
[llinoia morrisoni
Juniperus chinensis ‘Pfitzeriana’
Pyramid Chinese Juniper
Illinoia morrisoni
Juniperus scopulorum
Rocky Mountain Juniper

Leyland Cypress

Cinara sabinae
Juniperus squamata ‘Meyeri’
Meyer Singleseed Juniper
Cinara juniperi
Illinoia morrisoni
Thuja plicata
Illinoia morrisoni

Western Red Cedar

F. Pinaceae

Abies balsamea
Cinara curvipes
Cinara occidentalis

Abies grandis
Cinara confinis
Cinara curvipes
Cinara occidentalis

Balsam Fir

Grand Fir

54 J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DEc. 31, 1978

Cinara sonata
Mindarus abietinus

Abies lasiocarpa Alpine Fir
Cinara confinis

Abies sibirica Siberian Fir
Cinara occidentalis

Abies sp Fir

Cinara confinis
Cinara sonata

Larix occidentalis Western Larch
Cinara laricifoliae

Picea abies Norway Spruce
Cinara braggii

Picea engelmannii Engelmann Spruce

Cinara obscura
Cinara saskensis
Picea glauca White Spruce
Cinara costata
Cinara hottesi
Picea pungens Blue Spruce
Cinara brag gii
Cinara coloradensis
Cinara costata
Elatobium abietinum
Picea sitchensis Sitka Spruce
Cinara braggii
Cinara coloradensis
Cinara fornacula
Cinara nigripes
Cinara vandykei
Elatobium abietinum
Picea sp Spruce
Cinara fornacula
Elatobium abietinum
Pinus albicaulis Whitebark Pine
Cinara inscripta
Cinara oregoni
Pinus contorta var latifolia Lodgepole Pine
Cinara brevispinosa
Cinara medispinosa
Cinara murrayanae
Cinara pergandei
Pinus monticola Western White-Pine
Cinara ferrisi
Cinara kuchea

Pinus nigra Austrian Pine
Cinara pinea
Pinus ponderosa Ponderosa Pine

Cinara arizonica
Cinara ponderosae
Cinara thatcheri
Essigella gillettei
Schizolachnus curvispinosus
Pinus sylvestris Scots Pine
Cinara pinea
Schizolachnus pineti
Pseudotsuga menziesii Douglas Fir
Cinara pseudotaxifoliae
Cinara pseudotsugae
Cinara splendens
Essigella wilsoni
Tsuga heterophylla Western Hemlock

Cinara pilicornis
Cinara tsugae
Illinoia patriciae

F. Taxodiaceae
Sequoiadendron giganteum
Illinoia morrisoni

Giant Sequoia

CL. MAGNOLIOPSIDA (FLOWERING PLANTS—

DICOTYLEDONS)
F. Aceraceae

Acer circinatum Vine Maple
Periphyllus californiensis
Periphyllus testudinaceus

Acer ginnala Amur Maple
Periphyllus testudinaceus

Acer glabrum Rocky Mountain Maple

Drepanosiphum platanoidis
Periphyllus brevispinosus

Acer glabrum var douglasii Douglas Maple

Periphyllus testudinaceus

Acer macrophyllum Broadleaf Maple

Drepanosiphum platanoidis
Periphyllus lyropictus
Periphyllus testudinaceus
Acer negundo
Drepanosiphum platanoidis
Periphyllus californiensis
Periphyllus negundinis
Periphyllus testudinaceus

Box-Elder

Acer palmatum Japanese Maple

Periphyllus testudinaceus

Acer platanoides Norway Maple

Drepanosiphum platanoidis
Periphyllus lyropictus
Periphyllus testudinaceus
Acer rubrum

Periphyllus testudinaceus
Acer sp

Drepanosiphum platanoidis
Periphyllus californiensis
Periphyllus lyropictus
Periphyllus testudinaceus

F. Anacardiaceae
Rhus sp
Aphis fabae
Brachycaudus cardui

F. Apocynaceae

Red Maple

Maple

Sumac

Vinca major Big Periwinkle

Aulacorthum solani

Vinca minor Common Periwinkle

Macrosiphum euphorbiae
Rhopalosiphoninus staphyleae

F. Aquifoliaceae

Ilex x altaclarensis Altaclara Holly

Illinoia lam bersi
Macrosiphum rosae
Ilex aquifolium
Aphis fabae
Aulacorthum solani

English Holly

J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DEc. 31, 1978 55

Illinoia lam bersi
Macrosiphum euphorbiae
Macrosiphum rosae
Ilex aquifolium ‘Aureo-marginata’
Yellowedge English Holly
Illinoia lam bersi
Macrosiphum euphorbiae

Ilex glabra Inkberry
Macrosiphum rosae
Ilex integra Mochi Tree

Macrosiphum rosae

F. Araliaceae
Fatsia japonica
Aphis fabae
Hedera helix
Aphis fabae
Aphis hederae

Japan Fatsia

English Ivy

F. Balsaminaceae
Impatiens glandulifera
Aphis fabae

Indian Balsam

Impatiens sp Snap weed
Myzus ornatus
F. Begoniaceae
Begonia cucullata var hookeri Wax Begonia

Myzus ornatus

F. Berberidaceae
Berberis x hybrido-gagnepainii
False Black Barberry
Liosomaphis berberidis
Berberis thunbergii
Liosomaphis berberidis
Berberis verruculosa
Liosomaphis berberidis
Mahonia aquifolium
Liosomaphis berberidis

Japanese Barberry
Warty Barberry
Tall Oregon-Grape
F. Betulaceae
Alnus incana ssp tenuifolia

Thin-Leaved Mountain Alder
Oestlundiella flava

Alnus rubra Red Alder
Euceraphis gillettei
Euceraphis punctipennis
Pterocallis alni .
Alnus sp Alder

Boererina variabilis
Euceraphis gillettei
Oestlundiella flava
Pterocallis alni

Alnus viridis ssp sinuata

Sitka Mountain Alder

Boernerina variabilis
Euceraphis sitchensis

Betula occidentalis
Calaphis betulaefoliae
Euceraphis punctipennis
Symydobius intermedius

Betula papyrifera

Western Birch

Paper Birch

Asiphum tremulae
Calaphis betulicola
Betula papyrifera var papyrifera
Common Paper J irch
Euceraphis punctipennis
Betula pendula
Betulaphis quadrituberculata
Calaphis betulicola
Euceraphis punctipennis
Betula pendula ‘Dalecarlica’
Dalecarlia Weeping Birch
Callipterinella callipterus
Euceraphis punctipennis
Betula sp
Betulaphis aurea
Betulaphis brevipilosa
Betulaphis helvetica
Betulaphis quadrituberculata
Calaphis betulaecolens
Calaphis betulicola
Calaphis flava
Euceraphis gillettei
Euceraphis punctipennis
Hamamelistes spinosus
Carpinus betulus
Myzocallis carpini
Corylus avellana
Myzocallis coryli
Corylus cornuta
Illinoia spiraeae
Myzocallis coryli
Corylus sp
Myzocallis coryli

Weeping Birch

Birch

European Hornbeam
Hazelnut

Beaked Hazelnut

Filbert

F. Bignoniaceae
Incarvillea mairei var grandiflora
Bigflower Incarvillea
Aulacorthum solani
Macrosiphum euphorbiae
Jacaranda acutifolia Sharpleaf Jacaranda
Macrosiphum euphorbiae

F. Boraginaceae

Amsinckia intermedia
Pleotrichophorus amsinckii

Myosotis arvensis Field Forget-Me-Not
Aphis fabae

Aulacorthum solani
Macrosiphum euphorbiae
Myzus ascalonicus
Myzus ornatus

F. Buddlejaceae

Buddleja davidii
Myzus persicae

Fiddle-Neck

Orange-Eye Butterflybush

F. Callitrichaceae
Callitriche stagnalis
Myzodium knowltoni

Pond Water-Starwort

F. Calycanthaceae
Calycanthus fertilis
Aphis citricola

Pale Sweetshrub

56

F. Campanulaceae
Campanula persicifolia © Peachleaf Bellflower
Aulacorthum circum flexum
Myzus ornatus

F. Caprifoliaceae
Abelia x ‘Edward Goucher’
Edward Goucher Abelia
Myzus ornatus
Lonicera ciliosa
Hyadaphis foeniculi
Lonicera involucrata
Delphiniobium canadense
Illinoia crystleae
Sambucus racemosa ssp pubens var arborescens
Coastal American Red Elder
Aphis sam buci
Macrosiphum stanleyi
Sambucus racemosa ssp pubens var leucocarpa
Eastern American Red Elder
Aphis sam buci
Macrosiphum stanleyi
Symphoricarpos albus Common Snowberry
Aphthargelia symphoricarpi
Macrosiphum euphorbiae
Viburnum edule High Bush Cranberry
Acyrthosiphon macrosiphum
Aphis fabae
Prociphilus xylostei
Viburnum opulus ssp trilobum
American Bush Cranberry

Orange Honeysuckle

Black Twin-Berry

Aphis fabae
Ceruraphis eriophori
Ceruraphis viburnicola
Viburnum x bodnantense
Bodnantense Viburnum
Aulacorthum solani
Ceruraphis eriophori
Myzus ascalonicus
Myzus ornatus
Weigela ‘Eva Rathke’

Myzus ornatus

Eva Rathke Weigela

F. Caryophyllaceae
Cerastium fontanum ssp triviale
Mouse-Ear Chickweed
Myzus ascalonicus
Dianthus caryophyllus
Myzus persicae
Silene alba ssp alba
Myzus persicae
Spergularia rubra
Myzus certus
Stellaria media
Myzus ascalonicus
Myzus persicae
Stellaria sp
Myzus ascalonicus

Carnation
White Campion
Red Sandwort

Common Chickweed

Chickweed

F. Celastraceae
Euonymus alata
Aphis fabae

Winged Spindle Tree

J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DEc. 31, 1978

Euonymus europaea
Aphis fabae
Euonymus latifolia
Aphis fabae

Broadleaf Spindle Tree

F. Chenopodiaceae

Beta vulgaris

Aphis fabae

Myzus persicae
Chenopodium album
Aphis fabae

Hayhurstia atriplicis
Macrosiphum euphorbiae
Myzus persicae
Pemphigus populivenae

Sugar Beet

Lamb’s Quarters

Chenopodium glaucum Goosefoot
Aphis fabae
Salicornia europaea

Sitobion salicicornii

Sand-Fire

F. Cistaceae
Helianthemum nummularium
Myzus ornatus

Rock Rose

F. Compositae
Achillea millefolium
Macrosiphoniella mille folii
Anaphalis margaritacea Pearly Everlasting
Brachycaudus helichrysi
Illinoia richardsi
Uroleucon russellae
Artemisia tridentata
Aphis canae
Obtusicauda artemisiae
Aster alpinus
Macrosiphum subviride
Aster sp
Uroleucon am brosiae
Balsamorhiza sagittata Arrowleaf Balsamroot
Macrosiphum euphorbiae
Bellis perennis
Myzus ascalonicus
Bidens cernua
Aphis fabae
Myzus persicae
Calendula officinalis
Aphis fabae
Callistephus chinensis
Aphis fabae
Macrosiphum euphorbiae
Myzus persicae
Chamomilla suaveolens
Aphis fabae
Aulacorthum solani
Brachycaudus helichrysi
Macrosiphum euphorbiae
Myzus persicae
Chrysanthemum frutescens
Brachycaudus helichrysi
Chrysanthemum leucanthemum Ox-Eye Daisy
Macrosiphoniella mille folii
Chrysanthemum x morifolium
Florist’s Chrysanthemum

Common Yarrow

Sagebrush

Alpine Aster

Aster

English Daisy

Smooth Beggartick

Pot-Marigold

China Aster

Pineapple Weed

Marguerite

"

eee

(
European Spindle Tree _
t

(S

Aulacorthum circumflexum
Aulacorthum solani
Brachycaudus helichrysi
Macrosiphoniella sanborni
Macrosiphum euphorbiae
Myzus ornatus
Myzus persicae
Chrysothamnus nauseosus
Aphis chrysothamni
Cirsium arvense
Aphis fabae
Brachycaudus cardui
Macrosiphum euphorbiae
Uroleucon cirsii
Cirsium brevistylum
Capitophorus elaeagni
Uroleucon cirsii
Cirsium sp
Uroleucon cirsit
Cirsium undulatum
Brachycaudus cardui

Rabbit Bush

Canada Thistle

Indian Thistle

Thistle

Wavy-Leaved Thistle

Cirsium vulgare Bull Thistle
Bipersona ochrocentri

Dahlia sp Dahlia
Macrosiphum euphorbiae

Gnaphalium uliginosum Cudweed

Brachycaudus helichrysi
Grindelia integrifolia Entire-Leaved Gumweed
Uroleucon erigeronensis
Gynura aurantiaca
Macrosiphum euphorbiae
Myzus ornatus
Helianthus annuus

Aphis helianthi
Helianthus sp

Aphis helianthi
Hieracium aurantiacum
Macrosiphum euphorbiae
Hypochoeris radicata
Macrosiphum euphorbiae
Myzus ascalonicus
Myzus ornatus
Uroleucon ambrosiae

Lactuca biennis

Uroleucon pseudambrosiae
Lactuca sativa

Aphis fabae

Macrosiphum euphorbiae

Myzus persicae

Pemphigus populivenae
Lactuca serriola

Acyrthosiphon lactucae
Lactuca sp

Acyrthosiphon lactucae

Myzus ascalonicus

Myzus ornatus

Nasonovia ribisnigri
Lactuca tatarica ssp pulchella

Blue-Flowered Lettuce

Hyperomyzus lactucae

Macrosiphum euphorbiae
Lapsana communis

Velvet-Plant

Common Sunflower
Sunflower
Orange Hawkweed

Spotted Cat’s Ear

Tall Blue Lettuce

Garden Lettuce

Prickly Lettuce

Lettuce

Nipplewort

_ J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DrEc. 31, 1978 57

Aulacorthum solani
Macrosiphum euphorbiae
Myzus ornatus
Nasonovia ribisnigri
Senecio jacobaea

Aphis lugentis
Senecio vulgaris
Brachycaudus helichrysi
Macrosiphum euphorbiae
Myzus ornatus

Myzus persicae
Solidago canadensis

Uroleucon erigeronensis
Uroleucon nigrotuberculatum
Sonchus arvensis Perennial Sowthistle
Hyperomyzus lactucae
Hyperomyzus pallidus
Sonchus asper

Aphis fabae
Hyperomyzus lactucae

Uroleucon sonchi
Sonchus oleraceus
Hyperomyzus lactucae
Sonchus sp

Hyperomyzus lactucae
Myzus ascalonicus
Tagetes erecta
Macrosiphum euphorbiae

Tansy Ragwort

Common Groundsel

Golden-Rod

Spiny Sowthistle

Annual Sowthistle

Sowthistle

African Marigold

Tagetes tenuifolia ‘Pumila’ | Dwarf Marigold
Brachycaudus helichrysi
Tanacetum vulgare Tansy

Macrosiphoniella tanacetaria
Taraxacum officinale Common Dandelion
Myzus ascalonicus
Uroleucon taraxaci
Unknown sp
Illinoia magna
Zinnia elegans
Aphis fabae
Macrosiphum euphorbiae

Common Zinnia

F. Convolvulaceae
Calystegia sepium
Myzus persicae
Convolvulus arvensis
Myzus persicae

Hedge Bindweed

Dwarf Bindweed

F. Cornaceae
Aucuba japonica
Aulacorthum solani
Myzus ascalonicus
Cornus alba ‘Argenteo-marginata’
Creamedge Tartarian Dogwood
Aphis salicariae
Cornus alba ‘Sibirica’
Anoecia corni
Cornus ‘Eddie’s White Wonder’
Eddie White Wonder Dogwood
Aphis salicariae
Cornus florida
Aphis salicariae
Cornus florida ‘Pluribracteata’
Double Flowering Dogwood

Japanese Aucuba

Siberian Dogwood

Flowering Dogwood

58 J. ENTOMOL. Soc. Brit. COLUMBIA 75 (1978), DEc. 31, 1978

Aphis salicariae
Cornus kousa
Aphis salicariae
Cornus mas
Aphis salicariae
Cornus nuttallii Western Flowering Dogwood
Anoecia corni

Aphis salicariae

Macrosiphum euphorbiae

Cornus pur pusii
Anoecia corni
Aphis salicariae
Cornus racemosa
Aphis salicariae
Cornus sanguinea
Anoecia corni
Aphis salicariae
Cornus sericea
Anoecia corni
Aphis helianthi
Macrosiphum euphorbiae
Sitobion manitobense

Japanese Dogwood

Cornelian-Cherry Dogwood

Silky Dogwood

Gray Dogwood

Bloodtwig Dogwood

Red-Osier Dogwood

F. Crassulaceae
Sedum anglicum
Aphis sedi
Sedum sp
Aphis sedi

F. Cruciferae
Arabis caucasica
Myzus ornatus

English Stonecrop

Stonecrop

Wall Rockcress

Aubrieta deltoidea Aubrieta
Myzus ascalonicus
Myzus ornatus

Brassica napus var napobrassicae Rutabaga
Brevicoryne brassicae

Brassica oleracea var capitata Cabbage

Brevicoryne brassicae

Myzus persicae

Brassica oleracea var gemmifera

Brussels Sprouts

Brevicoryne brassicae
Lipaphis erysimi
Macrosiphum euphorbiae
Myzus persicae

Brassica pekinensis
Brevicoryne brassicae

Brassica rapa spp campestris
Lipaphis erysimi
Macrosiphum euphorbiae
Myzus persicae

Brassica rapa var lorifolius
Brevicoryne brassicae

Brassica sp

Myzus persicae

Capsella bursa-pastoris
Aphis fabae
Aulacorthum solani
Brachycaudus helichrysi
Myzus ascalonicus
Cardamine oligosperma
Myzus ascalonicus

Pe-Tsai

Bird Rape

Turnip

Mustard

Shepherd’s Purse

Bittercress

Hesperis matronalis Sweet Rocket
Myzus ascalonicus
Lunaria annua

Aphis fabae

Money Plant

Raphanus raphanistrum Charlock
Myzus persicae
Raphanus sativus Radish

Brevicoryne brassicae
Sisymbrium officinale
Lipaphis erysimi
Myzus ascalonicus
Myzus persicae
Sitobion fragariae

Tall Hedge Mustard

Sisymbrium sp Hedge Mustard
Myzus persicae

F. Cuscutaceae
Cuscuta sp Dodder

Myzus persicae
Cuscuta subinclusa
Aphis fabae
F. Ericaceae
Arbutus menziesii
Wahlgreniella nervata
Arctostaphylos uva-ursi
Aphis fabae
Fimbriaphis fimbriata
Myzus ascalonicus
Tamalia coweni
Calluna vulgaris
Aphis callunae
Daboecia cantabrica
[llinoia lam bersi
Daboecia cantabrica ‘Alba’ White Irish-Heath
Illinoia lambersi
Daboecia cantabrica ‘Atropurpurea’
Purple Irish-Heath

Long-Flowered Dodder

Pacific Madrone

Bearberry

Scotch Heather

Irish-Heath

Illinoia lam bersi
Daboecia cantabrica ‘Praegerae’
Rosy Irish-Heath
Illinoia lam bersi
Gaultheria shallon
Illinoia lam bersi
Sitobion dorsatum
Pieris japonica Japanese Andromeda
Aulacorthum pterinigrum
Wahlgreniella nervata
Rhododendron ‘Directeur Moerlands’
Directeur Moerlands Azalea
Illinoia lam bersi
Rhododendron ‘Elizabeth’
Elizabeth Rhododendron

Salal

Tilinoia lambersi
Rhododendron ‘Glacier’

Illinoia lam bersi
Rhododendron ‘Princess Elizabeth’

Princess Elizabeth Rhododendron

Illinoia lambersi
Rhododendron luteum

Illinoia lam bersi
Rhododendron molle

Illinoia lam bersi

Glacier Azalea

Pontic Azalea

Chinese Azalea

Re EN ee ee

J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DEc. 31, 1978 59

Rhododendron sp Rhododendron
Illinoia lam bersi

Vaccinium corymbosum Highbush Blueberry
Brachycaudus helichrysi
Fimbriaphis fimbriata

Vaccinium parvifolium
Macrosiphum parvifolii

Vaccinium sp
Aulacorthum pterinigrum
Fimbriaphis fimbriata

Red Huckleberry

Blueberry

F. Fagaceae
Castanea dentata
Myzocallis castanicola
Castanea sp
Myzocallis castanicola
Fagus grandifolia

American Chestnut
Chestnut

American Beech

Phyllaphis fagi

Fagus sylvatica European Beech
Phyllaphis fagi

Fagus sylvatica ‘Atropunicea’ Copper Beech
Phyllaphis fagi

Nothofagus antarctica Antarctic Falsebeech
Macrosiphum euphorbiae
Quercus coccinea
Myzocallis multisetis
Quercus garryana
Thelaxes californica
Tuberculatus annulatus
Tuberculatus colum biae
Quercus macrocarpa
Myzocallis punctatus
Quercus prinus
Myzocallis punctatus
Thelaxes californica
Quercus robur
Tuberculatus annulatus
Quercus robur ‘Fastigiata’
Upright English Oak
Tuberculatus annulatus
Quercus rubra
Myzocallis occultus
Myzocallis walshii
Quercus sp Oak
Thelaxes californica
Tuberculatus annulatus

Scarlet Oak

Garry Oak

Bur Oak

Chestnut Oak

English Oak

Red Oak

F. Fumariaceae
Dicentra formosa
Macrosiphum euphorbiae

Bleeding Heart

F. Geraniaceae
Erodium cicutarium ssp cicutarium
Common Stork’s-Bill
Aulacorthum solani
Myzus ascalonicus
Geranium molle
Myzus ascalonicus
Geranium sp
Aulacorthum solani
Geranium viscosissimum var viscosissimum
Sticky Purple Crane’s-Bill
Amphorophora geranii

Dove’s-Foot Crane’s-Bill

Crane’s-Bill

Macrosiphum aetheocornum
Pelargonium x hortorum
Aulacorthum circumflexum

Fish Geranium

F. Gesneriaceae
Aeschynanthus radicans
Aulacorthum solani
Saintpaulia ionantha Common African Violet
Idiopterus nephrelepidis
Saintpaulia sp
Aulacorthum circumflexum

Lipstick Plant

African Violet

F. Grossulariaceae
Escallonia x langleyensis Hybrid Escallonia
Macrosiphum euphorbiae
Ribes lacustre
Aphis neomexicana
Macrosiphum bisensoriatum
Ribes laxiflorum Trailing Black Currant
Aphis neomexicana
Cryptomyzus galeopsidis
Hyperomyzus lactucae
Ribes sanguineum Red Flowering Currant
Aphis neomexicana

Swamp Gooseberry

Ribes sativum Red Currant
Cryptomyzus galeopsidis
Cryptomyzus ribis

Ribes sp Currant

Cryptomyzus ribis
Ribes grossularia uva-crispa
English Gooseberry
Cryptomyzus ribis

F. Guttiferae
Hypericum patulum ‘Hidcote’
Hidcote St-John’s-Wort
Myzus ornatus
Wahlgreniella nervata

F. Hydrangeaceae
Deutzia gracilis
Aphis fabae
Macrosiphum euphorbiae
Rhopalosiphoninus hydrangeae
Deutzia x rosea ‘Carminea’
Rosepanicle Deutzia
Macrosiphum euphorbiae
Myzus ornatus
Philadelphus lewisii
Aphis fabae
Aulacorthum solani
Brachycaudus helichrysi
Glendenningia philadelphi
Illinoia spiraeae
Macrosiphum euphorbiae
Myzus ornatus
Myzus persicae
Philadelphus sp
Aphis fabae
Brachycaudus helichrysi
Philadelphus x virginalis
Virginalis Mock Orange

Slender Deutzia

Lewis’ Mock Orange

Mock Orange

Aphis fabae

60 J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DrEc. 31, 1978

Brachycaudus helichrysi
Macrosiphum euphorbiae
Myzus ornatus
Myzus persicae

F. Juglandaceae

Juglans regia English Walnut
Callaphis juglandis

Juglans sp Walnut
Chromaphis juglandicola

F. Labiatae

Galeopsis tetrahit
Cryptomyzus ribis

Lamium amplexicaule
Myzus ornatus

Mentha arvensis ssp borealis
Aulacorthum solani
Capitophorus elaeagni
Ovatus crataegarius

Mentha spicata

Myzus ornatus

Nepeta cataria
Aulacorthum solani
Myzus ornatus

Rosmarinus officinalis
Myzus ornatus

Thymus pseudolanuginosus

Woolly Mother-Of-Thyme

Hemp Nettle
Henbit

Field Mint

Spearmint

Catnip

Rosemary

Myzus ornatus

F. Lauraceae
Sassafras albidum
Aphis fabae

Sassafras

F. Leguminosae
Caragana arborescens
Acyrthosiphon caraganae
Colutea arborescens
Acyrthosiphon caraganae
Colutea melanocalyx Black Bladder-Senna
Acyrthosiphon caraganae
Cytisus hirsutus var demissus
Aphis cytisorum
Cytisus scoparius
Acyrthosiphon pisum
Ctenocallis setosus
Laburnum anagyroides
Aphis craccivora
Laburnum x watereri
Aphis cytisorum
Lathyrus nevadensis ssp lanceolatus
Nuttall’s Peavine

Siberian Peashrub

Bladder-Senna

Dwarf Broom

Scotch Broom

Golden Chain

Waterer Laburnum

Nearctaphis sclerosa
Lupinus sp
Acyrthosiphon pisum
Macrosiphum albifrons
Medicago sativa
Acyrthosiphon pisum
Macrosiphum euphorbiae
Myzus persicae
Melilotus alba
Acyrthosiphon pisum

Perennial Lupine

Alfalfa

White Sweet Clover

Macrosiphum euphorbiae
Therioaphis riehmi
Melilotus sp
Acyrthosiphon pisum

Sweet Clover

Pisum sativum Garden Pea
Myzus persicae

Pisum sativum var arvense Field Pea
Acyrthosiphon pisum

Robinia sp False Acacia

Appendiseta robiniae
Sophora japonica
Appendiseta robiniae
Spartium junceum
Aphis craccivora
Trifolium pratense
Aulacorthum solani
Brachycaudus helichrysi
Myzus ornatus
Nearctaphis sensoriata
Trifolium sp
Acyrthosiphon pisum
Nearctaphis bakeri
Unknown sp

Nearctaphis crataegifoliae
Vicia faba

Aphis fabae

Myzus persicae
Vicia sativa var angustifolia

Narrow-Leaved Vetch

Acyrthosiphon pisum

Aulacorthum solani

Japanese Pagoda Tree
Spanish Broom

Red Clover

Clover

Broad Bean

F. Magnoliaceae

Liriodendron tulipifera
Aphis fabae

Fimbriaphis fimbriata
Hyalopterus pruni
Illinoia liriodendri
Macrosiphum euphorbiae
Myzus cerasi
Rhopalosiphum insertum

Tulip Tree

F. Malvaceae
Hibiscus calyphyllus
Aulacorthum solani
Hibiscus rosa-sinensis
Macrosiphum euphorbiae
Myzus persicae
Hibiscus sp
Myzus persicae

Lemon-Yellow Hibiscus

Chinese Hibiscus

Hibiscus

F. Moraceae
Ficus carica
Aphis fabae
Humulus lupulus
Phorodon humuli

Common Fig

Common Hop

F. Nymphaeaceae
Nuphar lutea ssp polysepala Indian Pond Lily
Macrosiphum audeni

Nuphar sp Cow-Lily
Rhopalosiphum nymphaeae
Nymphaea sp Waterlily

Rhopalosiphum nymphaeae

J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DEc. 31, 1978 61

F. Oleaceae
Forsythia sp
Macrosiphum euphorbiae
Forsythia x intermedia
Myzus ornatus
Ligustrum vulgare
Myzus ligustri

Forsythia
Border Forsythia

Common Privet

F. Onagraceae

Epilobium alpinum

Aphis varians

Epilobium angustifolium

Aphis praeterita

Aphis salicariae

Macrosiphum fuscicornis

Epilobium ciliatum
Purple-Leaved Willow-Herb

Alpine Willow-Herb

Fireweed

Aphis epilobii

Myzus persicae
Epilobium sp

Aphis salicariae

Macrosiphum euphorbiae
Fuchsia x hybrida

Macrosiphum euphorbiae
Fuchsia magellanica

Myzus ornatus

Fuchsia sp

Myzus ornatus

Willow-Herb

Common Fuchsia
Hardy Fuchsia

Fuchsia

F. Oxalidaceae
Oxalis corniculata
Creeping Yellow Wood-Sorrel
Aulacorthum circumflexum
Myzus ornatus
Oxalis deppei
Aphis fabae

F. Papaveraceae
Meconopsis betonicifolia
Aulacorthum solani
Myzus ascalonicus
Meconopsis cambrica
Aphis fabae
Meconopsis paniculata
Aulacorthum solani
Myzus persicae
Papaver orientale
Aulacorthum circumflexum
Aulacorthum solani

Good-Luck Leaf

Blue- Poppy

Welsh Poppy

Nepal Poppy

Oriental Poppy

F. Plantaginaceae
Plantago lanceolata
Myzus ascalonicus
Plantago major
Myzus persicae

Ribgrass

Common Plantain

E. Plumbaginaceae
Trientalis latifolia
Aulacorthum solani
Myzus persicae

Broad-Leaved Starflower

E. Polemoniaceae
Phlox paniculata
Aphis fabae
Myzus ascalonicus

Perennial Phlox

E. Polygonaceae
Fallopia convolvulus
Myzus persicae
Polygonum lapathifolium
Curltop Lady’s Thumb
Capitophorus hippophaes
Polygonum persicaria
Aphis fabae
Capitophorus hippophaes
Reynoutria japonica Japanese Knotweed
Aulacorthum solani
Rheum rhabarbarum
Aphis fabae
Macrosiphum euphorbiae
Myzus ascalonicus
Myzus ornatus
Myzus persicae
Rumex acetosella
Brachycaudus rumexicolens
Myzus ascalonicus
Pemphigus populivenae
Rumex crispus
Aphis rumicis

Black Bindweed

Lady’s Thumb

Rhubarb

Sheep Sorrel

Curled Dock

F. Portulacaceae
Claytonia sibirica var sibirica
Siberian Spring-Beauty
Macrosiphum euphorbiae
Myzus ascalonicus
Portulaca oleracea
Myzus persicae

Common Purslane

E. Primulaceae
Androsace sarmentosa
Aulacorthum solani

Lysimachia punctata
Aphis fabae
Aulacorthum solani

Primula alpicola ssp luna Moonlight Primrose
Myzus ornatus

Primula auricula
Aulacorthum solani

Primula denticulata
Aulacorthum solani

Primula juliae ‘Wanda’
Aulacorthum solani

Primula sp
Aulacorthum circum flexum
Aulacorthum solani
Myzus ornatus

Primula veris
Aulacorthum solani

Primula vialii
Aulacorthum solani

Rock-Jasmine

Yellow Loosestrife

Auricula Primrose
Himalayan Primrose
Wanda Primrose

Primrose

Cowslip Primrose

Littons Primrose

F. Ranunculaceae
Anemone pulsatilla
Myzus ascalonicus
Aquilegia alpina
Kakimia aquilegiae
Aquilegia formosa
Kakimia aquilegiae
Aquilegia sp

European Pasqueflower
Alpine Columbine
Sitka Columbine

Columbine

62 J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), Dec. 31, 1978

Aulacorthum solani
Kakimia aquilegiae
Longicaudus trirhodus
Caltha sp

Rhopalosiphum nymphaeae
Clematis ‘Nelly Moser’ Nelly Moser Clematis
Aulacorthum solani
Delphinium x cultorum Perennial Delphinium
Kakimia wahinkae
Helleborus niger
Aulacorthum solani
Ranunculus acris
Aulacorthum solani
Myzus persicae
Ranunculus occidentalis
Myzus ascalonicus
Myzus ornatus
Thecabius affinis
Ranunculus sp

Aphis fabae

Myzus ornatus
Myzus persicae

Marsh Marigold

Christmas Rose

Tall Buttercup

Western Buttercup

Buttercup

F. Rhamnaceae
Ceanothus sanguineus
Aphis ceanothi
Ceanothus velutinus
Aphis ceanothi
Rhamnus purshiana
Sitobion rhamni

Wild Lilac
Sticky Laurel

Cascara

F. Rosaceae
Amelanchier alnifolia | Western Serviceberry
Acyrthosiphon macrosiphum
Prociphilus alnifoliae
Amelanchier canadensis
Shadblow Serviceberry
Acyrthosiphon macrosiphum
Aphis fabae
Aphis pomi
Prociphilus alnifoliae
Amelanchier laevis Allegheny Serviceberry
Acyrthosiphon macrosiphum
Fimbriaphis gentneri
Amelanchier ovalis
Fimbriaphis gentneri
Amelanchier sp
Nearctaphis sensoriata
Prociphilus alnifoliae
Prociphilus corrugatans
Chaenomeles japonica
Lesser Flowering Quince

European Serviceberry

Serviceberry

Aphis pomi

Brachycaudus helichrysi

Macrosiphum euphorbiae

Rhopalosiphum insertum

Rhopalosiphum nymphaeae
Cotoneaster bullatus Hollyberry Cotoneaster

Aphis pomi
Cotoneaster dammeri Bearberry Cotoneaster
Aphis nomi

Cotoneaster henryanus Henry’s Cotoneaster
Aphis pomi

Cotoneaster hoizontalis Rock Cotoneaster
Aphis pomi
Cotoneaster salicifolius ‘Repens’
Creeping Willowleaf Cotoneaster
Aphis pomi
Cotoneaster sp
Aphis pomi
Eriosoma lanigerum
Crataegus douglasii
Aphis pomi
Fimbriaphis gentneri
Nearctaphis bakeri
Nearctaphis sclerosa
Crataegus laevigata ‘Paul’s Scarlet’
Paul’s Scarlet Hawthorn
Metopolophium dirhodum
Crataegus monogyna Singleseed Hawthorn
Aphis pomi
Fimbriaphis gentneri
Crataegus sp
Aphis pomi
Metopolophium dirhodum
Nearctaphis crataegifoliae
Nearctaphis sclerosa
Rhopalosiphum insertum
Fragaria x ananassa
Aphis forbesi
Aulacorthum solani
Chaetosiphon fragaefolii
Macrosiphum euphorbiae
Myzus ascalonicus
Fragaria sp
Acyrthosiphon malvae rogersii
Acyrthosiphon pisum
Chaetosiphon fragaefolii
Fimbriaphis fim briata
Macrosiphum euphorbiae
Myzus ascalonicus
Myzus ornatus
Myzus persicae
Fragaria vesca
Aulacorthum solani
Myzus ornatus
Myzus persicae
Fragaria vesca ssp bracteata Wild Strawberry
Aphis forbesi
Fragaria virginiana
Chaetosiphon fragaefolii
Fragaria virginiana ssp glauca
Blueleaf Strawberry
Chaetosiphon fragaefolii
Geum macrophyllum Large-Leaved Avens
Amphorophora rossi
Macrosiphum euphorbiae
Myzus ascalonicus
Holodiscus discolor
Aphis craccivora
Aphis fabae
Macrosiphum euphorbiae
Malus coronaria Wild Sweet Crabapple
Aphis pomi
Malus domestica
Eriosoma lanigerum

Cotoneaster

Douglas Hawthorn

Hawthorn

Chilean Strawberry

Strawberry

Woods Strawberry

Virginia Strawberry

Ocean-Spray

Common Apple

\

Macrosiphum euphorbiae
Rhopalosiphum insertum
Malus fusca

Eriosoma lanigerum

Malus ioensis

Aphis pomi

Dysaphis plantaginea
Rhopalosiphum insertum

Pacific Crabapple

Prairie Crabapple

Malus sp Ornamental & Table Crabapple
Aphis pomi
Dysaphis plantaginea

Rhopalosiphum insertum
Malus sylvestris

Aphis pomi

Dysaphis plantaginea
Nearctaphis bakeri
Mespilus germanica
Fimbriaphis gentneri
Rhopalosiphum insertum
Oemleria cerasiformis
Macrosiphum euphorbiae
Macrosiphum osmaroniae

Photinia x fraseri

Aphis pomi

Macrosiphum euphorbiae
Physocar pus capitatus

Utamphorophora humboladti
Physocarpus malvaceus

Utamphorophora hum boldti
Potentilla anserina

Chaetosiphon fragae folii

Chaetosiphon potentillae
Prunus avium

Hyalopterus pruni

Myzus cerasi

Nearctaphis bakeri

Rhopalosiphum nymphaeae
Prunus cerasifera

Myzus cerasi
Prunus cerasifera ‘Atropurpurea’

Pissard Plum

Apple

Medlar

Indian-Plum

Fraser Photinia

Pacific Ninebark
Mallow Ninebark

Silver Weed

Sweet Cherry

Cherry Plum

Brachycaudus helichrysi
Phorodon humuli

Prunus cerasus

Myzus cerasi

Prunus domestica
Brachycaudus cardui
Brachycaudus helichrysi
Hyalopterus pruni
Myzus lythri

Myzus persicae
Nearctaphis bakeri
Phorodon humuli
Rhopalosiphum nymphaeae
Rhopalosiphum padi
Prunus emarginata
Myzus cerasi
Myzus lythri
Prunus japonica
Phorodon humuli
Prunus persica
Aphis pomi

Sour Cherry

Garden Plum

Bitter Cherry

Japanese Bush Cherry

Peach

J. ENTOMOL. Soc. Brit. COLUMBIA 75 (1978), DEc. 31, 1978 63

Myzus persicae
Rhopalosiphum nymphaeae
Prunus ‘Royal Anne’
Royal Anne Flowering Cherry
Myzus cerasi
Prunus serrulata ‘Kwanzan’
Kwanzan Oriental Cherry
Myzus cerasi
Prunus sp
Brachycaudus helichrysi
Hyalopterus pruni
Myzus cerasi
Rhopalosiphum cerasifoliae
Rhopalosiphum nymphaeae
Prunus virginiana Common Chokecherry
Asiphonaphis pruni
Rhopalosiphum cerasifoliae
Rhopalosiphum padi
Prunus virginiana ssp demissa
Western Chokecherry
Rhopalosiphum cerasifoliae
Pyracantha crenulata ‘Flava’
Yellow Nepal Firethorn

Cherry

Aphis pomi
Pyrus communis
Aphis pomi
Rosa nutkana Nootka Rose
Eomacrosiphon nigromaculosum
Rosa rugosa Rugose-Leaved Rose
Chaetosiphon tetrarhodum
Macrosiphum euphorbiae
Macrosiphum rosae
Metopolophium dirhodum
Rosa sp
Chaetosiphon fragaefolii
Chaetosiphon tetrarhodum
Fimbriaphis fimbriata
Macrosiphum euphorbiae
Macrosiphum rosae
Maculolachnus sijpkensi
Metopolophium dirhodum
Myzus persicae
Placoaphis siphunculata
Pseudocercidis rosae
Pterocallis alni
Wahlgreniella nervata
Rubus discolor Himalaya Blackberry
Amphorophora parviflori
Sitobion fragariae
Rubus idaeus
Amphorophora agathonica
Aphis idaei
Macrosiphum euphorbiae
Sitobion fragariae
Rubus laciniatus
Sitobion fragariae
Rubus x loganobaccus
Aphis idaei
Rubus occidentalis Blackcap Raspberry
Amphorophora agathonica

Rubus parviflorus
Amphorophora parviflori

Pear

Rose

Red Raspberry

Cut-Leaved Blackberry

Loganberry

Thimbleberry

64

Illinoia davidsoni
Illinoia maxima
Rubus sp
Sitobion fragariae
Rubus spectabilis
Amphorophora forbesi
Aulacorthum capilanoense
Macrosiphum euphorbiae
Rubus ursinus
Amphorophora parviflori
Amphorophora rubitoxica
Sorbus aucuparia
Aphis pomi
Sorbus scopulina
Nearctaphis yohoensis
Sorbus sitchensis ssp grayi

J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), Dec. 31, 1978

Bramble

Salmonberry

Douglasberry

Rowan Tree

Wid Mountain Ash

Western Sitka Mountain Ash

Macrosiphum pyrifoliae
Spiraea douglasii
Eoessigia longicauda
Illinoia spiraeae
Macrosiphum euphorbiae
Spiraea sp
Eoessigia longicauda
Spiraea thunbergii
Tllinoia spiraecola
Spiraea x arguta
Illinoia spiraeae
Spiraea x bumalda
Illinoia spiraeae
Stranvaesia davidiana
Aphis citricola

F. Rubiaceae

Hardhack

Spirea

Thunberg Spirea
Garland Spirea
Bumalda Spirea

Chinese Stranvaesia

Galium aparine Cleavers
Myzus persicae
Galium mollugo White Bedstraw

Aphis fabae

Myzus cerasi
Myzus ornatus
Gardenia jasminoides
Myzus ornatus

F. Salicaceae
Populus balsamifera
Pterocomma bicolor
Populus nigra ‘Italica’
Pemphigus bursarius
Pemphigus spyrothecae
Pterocomma bicolor

Populus sp
Chaitophorus populicola
Chaitophorus populifolii neglectus
Chaitophorus stevensis
Pemphigus monophagus
Pemphigus populivenae
Pterocomma bicolor
Pterocomma salicis
Populus tremuloides
Chaitophorus populicola
Chaitophorus populifolii neglectus
Populus trichocarpa

Common Gardenia

Balsam Poplar

Lombardy Poplar

Poplar

Trembling Aspen

Black Cottonwood

Chaitophorus populicola
Chaitophorus populifolii
Pemphigus populicaulis
Pemphigus populivenae
Pterocomma bicolor
Pterocomma smithiae
Thecabius gravicornis
Thecabius populimonilis
Salix babylonica
Pterocomma sanguiceps
Pterocomma smithiae

Salix exigua Silver-Leaved Willow
Chaitophorus macrostachyae

Weeping Willow

Salix fragilis Brittle Willow
Pterocomma smithiae
Salix lasiandra Pacific Willow

Cavariella konoi
Cavariella pastinacae
Pterocomma smithiae
Salix scouleriana

Aphis farinosa
Macrosiphum californicum
Pterocomma salicis
Pterocomma sanguiceps

Scouler’s Willow

Salix sitchensis Sitka Willow
Aphis farinosa
Salix sp Willow

Aphis farinosa

Cavariella pastinacae
Chaitophorus macrostachyae
Chaitophorus monelli
Chaitophorus nigrae
Chaitophorus pustulatus
Chaitophorus viminalis
Fullawaya bulbosa
Macrosiphum californicum
Macrosiphum euphorbiae
Plocamaphis flocculosa
Pterocomma bicolor
Pterocomma pilosum
Pterocomma salicis
Pterocomma sanguiceps
Tuberolachnus salignus

F. Saururaceae
Saururus cernuus Common Lizardtail
Rhopalosiphum nymphaeae

F. Scrophulariaceae
Antirrhinum majus Common Snapdragon
Brachycaudus helichrysi
Digitalis purpurea
Aulacorthum solani
Paulownia tomentosa
Aulacorthum solani

Common Foxglove

Royal Paulownia

F. Solanaceae

Capsicum sp Pepper
Myzus persicae
Lycopersicon esculentum Tomato

Aphis fabae
Physalis alkekengi
Aphis fabae

Chinese Lantern

J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DEc. 31, 1978 65

Myzus persicae

Solanum nigrum Nightshade
Myzus persicae
Solanum tuberosum Potato

Aphis fabae

Aulacorthum solani
Macrosiphum euphorbiae
Myzus persicae
Rhopalosiphoninus latysiphon

F. Styracaceae
Halesia carolina
Macrosiphum euphorbiae
Myzus ornatus

Carolina Silverbell

F. Thymelaeaceae

Daphne cneorum
Macrosiphum euphorbiae

Daphne laureola
Macrosiphum euphorbiae

Garland Flower

Spurge-Laurel

F. Tiliaceae
Tilia americana
Aulacorthum solani
Eucallipterus tiliae

American Linden

Tilia petiolaris Weeping White Linden
Eucallipterus tiliae
Tilia sp Linden

Eucallipterus tiliae

F. Tropaeolaceae
Tropaeolum majus
Aphis fabae
Aulacorthum solani

Common Nasturtium

F. Ulmaceae
Ulmus americana
Tinocallis platani
Ulmus sp
Eriosoma americanum
Tinocallis ulmifolii

F. Umbelliferae
Anethum graveolens Dill
Cavariella aegopodii

American Elm

Elm

Apium graveolens Celery
Aulacorthum solani

Cavariella konoi

Myzus persicae
Daucus carota Carrot

Aulacorthum solani
Cavariella aegopodii
Myzus persicae
Heracleum sphondylium ssp montanum
Cow Parsnip
Aphis heraclella
Aulacorthum solani
Cavariella pastinacae
Macrosiphum euphorbiae
Myzus ascalonicus
Oenanthe sarmentosa
Cavariella aegopodii
Osmorhiza chilensis

Water Parsley

Sweet Cicely

Myzus ascalonicus

Pastinaca sativa Parsnip
Aphis heraclella
Cavariella aegopodii

Petroselinum crispum Parsley

Cavariella aegopodii
Myzus ornatus
Sium suave

Aphis heraclella
Cavariella aegopodii

Water Parsnip

F. Urticaceae
Urtica dioica ssp gracilis var lyallii
Lyall’s Nettle
Macrosiphum euphorbiae

F. Verbenaceae
Verbena x hybrida
Brachycaudus helichrysi
Macrosiphum euphorbiae

Garden Verbena

F. Violaceae

Viola sp

Myzus ascalonicus
Viola tricolor European Wild Pansy
Aulacorthum circum flexum

Myzus ascalonicus

Myzus ornatus

Myzus persicae

Violet

CL. LILIOPSIDA (FLOWERING PLANTS —
MONOCOTYLEDONS)
F. Alismataceae
Alisma plantago-aquatica
American Waterplantain
Rhopalosiphum nymphaeae

F. Amaryllidaceae
Alstroemeria aurantiaca Yellow Alstroemeria
Myzus ornatus
Triteleia hyacinthina
Aulacorthum solani

Wild Hyacinth

F. Araceae
Philodendron hastatum
Spadeleaf Philodendron

Myzus ornatus

F. Araliaceae
Aralia elata
Myzus persicae

Japanese Angelica-Tree

F. Cyperaceae

Carex sitchensis Sitka Sedge
Ceruraphis eriophori
Thripsaphis cyperi

Carex sp Sedge

Ceruraphis eriophori
Iziphya umbella
Sitobion caricis
Thripsaphis cyperi
Thripsaphis verrucosa
Scirpus lacustris ssp validus var validus
Softstem Bulrush

66

Sitobion avenae
Sitobion fragariae
Scirpus microcarpus
Ceruraphis eriophori
Scirpus sp
Rhopalosiphum padi

Small-Flowered Bulrush

Bulrush

F. Gramineae
Agropyron repens
Sipha elegans
Tetraneura ulmi
Utamphorophora humboldti
Agropyron sp
Sipha elegans
Sitobion avenae
Agrostis stolonifera var palustris
Creeping Bentgrass

Couch Grass

Wheat Grass

Sipha glyceriae
Avena Sativa
Metopolophium dirhodum
Rhopalosiphum padi
Sitobion avenae
Calamagrostis sp
Sitobion fragariae
Cinna latifolia
Rhopalosiphum padi
Sitobion fragariae
Cortaderia selloana
Hyalopterus pruni
Sitobion fragariae
Dactylis glomerata
Hyalopteroides humilis
Holcus lanatus
Hyalopteroides humilis
Hordeum vulgare
Metopolophium dirhodum
Rhopalosiphum maidis
Rhopalosiphum padi
Sitobion avenae
Sitobion fragariae
Phragmites australis ssp australis
Common Reed

Oat

Reedgrass

Woodreed Grass

Pampas Grass

Orchard Grass
Velvet Grass

Barley

Hyalopterus pruni

Poa annua Low Spear Grass
Rhopalomyzus poae

Poa sp Meadow Grass

Rhopalosiphum padiformis
Pseudosasa japonica
Takecallis arundinariae
Secale cereale
Rhopalosiphum padi
Sitobion avenae
Triticum x aestivum
Rhopalosiphum padi
Sitobion avenae
Unknown sp
Aulacorthum solani
Diuraphis nodulus
Jacksonia papillata
Rhopalomyzus poae
Rhopalosiphum padi
Sipha elegans

Arrow Bamboo

Rye

Cultivated Wheat

J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DEc. 31, 1978

Sitobion avenae

Sitobion fragariae
Tetraneura ulmi

Uroleucon taraxaci
Utamphorophora humboldti
Zea mays

Macrosiphum euphorbiae
Sitobion avenae

Corn

F. Hydrocharitaceae
Elodea canadensis Canadian Waterweed
Rhopalosiphum nymphaeae

F. Iridaceae
Crocosmia x crocosmiiflora
Aphis fabae
Gladiolus x hortulanus
Aphis fabae
Macrosiphum euphorbiae
Gladiolus sp
Myzus ornatus
Iris kaempferi
Macrosiphum euphorbiae
Iris sp Iris
Aulacorthum circumflexum

Montbretia

Garden Gladiolus

Gladiolus

Japanese Iris

F. Juncaceae
Juncus articulatus
Schizaphis palustris
Sitobion avenae
Juncus bufonius
Sitobion avenae
Sitobion fragariae
Juncus tenuis
Schizaphis palustris

Jointed Rush

Toad Rush

Slender Rush

F. Juncaginaceae
Triglochin maritimum
Sitobion avenae

Seaside Arrow-Grass

F. Liliaceae
Allium schoenoprasum
Myzus ascalonicus
Hosta sieboldiana
Aulacorthum solani
Macrosiphum euphorbiae
Hosta undulata Wavy-Leaved Plantainlily
Aphis fabae
Lilium longiflorum
Aulacorthum circumflexum
Lilium speciosum
Myzus ascalonicus
Lilium szovitsianum
Aulacorthum solani
Lilium x hollandicum
Aulacorthum solani
Maianthemum kamtschaticum
Wild Lily-Of-The- Valley
Macrosiphum euphorbiae
Smilacina stellata
Star-Flowered Solomon’s Seal
Sitobion insulare yagasogae

Chive

Siebold Plantainlily

Trumpet Lily
Showy Lily
Szovitz Lily

Candlestick Lily

J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), Dec. 31, 1978 67

Tulipa gesneriana Tulip Zigadenus sp Deathcamus
Aulacorthum circumflexum Macrosiphum kiowanepus
Aulacorthum solani
Dysaphis tulipae F. Orchidaceae
Macrosiphum euphorbiae Epidendrum ibaguense Buttonhole Orchid
Myzus persicae Myzus persicae
Rhopalosiphoninus staphyleae
Yucca filamentosa Adams Needle EK. Typhaceae
Aphis fabae Typha latifolia Common Cat-Tail
Aulacorthum circumflexum Hyalopterus pruni
Macrosiphum euphorbiae Rhopalosiphum enigmae

Myzus persicae

REFERENCES

Crabbe, J. A., A. C. Jermy and J. T. Mickel. 1975. A new generic sequence for the pteridophyte
herbarium. Fern Gaz. 11 (2 & 3) :141-162.

Cronquist, A. 1968. The evolution and classification of flowering plants. p. 365-374. Houghton
Mifflin Co., Boston.

Cronquist, A. 1971. Introductory Botany. 2nd ed. p. 85-86. Harper & Brothers, Publishers, N.Y.

Eastop, V. F., and D. Hille Ris Lambers. 1976. Survey of the world’s aphids. Dr. W. Junk b.v.,
Publishers, The Hague.

Forbes, A. R., and Cho-Kai Chan. 1976. The aphids (Homoptera: Aphididae) of British Columbia.
4. Further additions and corrections. J. ent. Soc. Brit. Columbia 73:57-63.

Forbes, A. R., and Cho-Kai Chan. 1978. The aphids (Homoptera: Aphididae) of British Columbia.
6. Further additions. J. ent. Soc. Brit. Columbia 75: 47-52.

Forbes, A. R., and B. D. Frazer. 1973. The aphids (Homoptera: Aphididae) of British Columbia.
2. A host plant catalogue. J. ent. Soc. Brit. Columbia 70:58-68.

Forbes, A. R., B. D. Frazer and Cho-Kai Chan. 1974. The aphids (Homoptera: Aphididae) of British
Columbia. 3. Additions and corrections. J. ent. Soc. Brit. Columbia 71:43-49.

Forbes, A. R., B. D. Frazer and H. R. MacCarthy. 1973. The aphids (Homoptera: Aphididae) of
British Columbia. 1. A basic taxonomic list. J. ent. Soc. Brit. Columbia 70:43-57.

Hitchcock, C. L., and A. Cronquist. 1973. Flora of the Pacific Northwest. Univ. of Washington
Press, Seattle & London. 730 pp.

Hortus Third: A dictionary of plants cultivated in the United States and Canada. 1976. Revised
and Expanded by the Staff of the L. H. Bailey Hortorium. Cornell Univ. (Illus.),
MacMillan Publishing Co., N.Y.

Raworth, D. A., and B.D. Frazer. 1976. Compilation of taxonomic catalogues by computer. J. ent.
Soc. Brit. Columbia 73:63-67.

Schofield, W. B. 1969. Some common mosses of British Columbia. Handbook No. 28. Brit.
Columbia Prov. Mus. 262 pp.

Taylor, R. L., and B. MacBryde. 1977. Vascular plants of British Columbia — A descriptive
resource inventory. Tech. Bull. No. 4. The botanical garden. Univ. of B.C.

68 J. ENTOMOL. Soc. BRIT. COLUMBIA 75 (1978), DEc. 31, 1978

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