Bug vs. bug: nature's method of controlling injurious species

LIBRARY

OF THE

UNIVERSITY OF CALIFORNIA.

GIFT OF"

}

STATE. HORTICULTURAL COMMISSION

ELLWOOD COOPER, Commissioner

BUG V5. BUG

Nature's Method of Controlling
Injurious Species

BY

JOHN I5AAC

Reprinted from the First Biennial Report of the
State Horticultural Commissioner.

W. W. SHANNON,

SACRA MLNTO

1906

SUPT. STATE. PRINTING

CALIFORNIA STATE COMMISSION OF HORTICULTURE..

ELLWOOD COOPER Commissioner Santa Barbara

JOHN ISAAC Secretary San Francisco

ED. M. EHRHORN Deputy Mountain View

E. K. CARNES Assistant... .Riverside

O. E. BREMNER Assistant ._ Santa Rosa

CHAS. T. PAINE. ... .Assistant ..Redlands

GERTRUDE BIRD Stenographer Sacramento

OFFICE:

ROOM 41, STATE CAPITOL, SACRAMENTO.
BRANCH OFFICE, ROOM 11, FERRY BUILDING, SAN FRANCISCO.

„. THE

UNIVERSITY

OF

BUG VS. BUG.

BY JOHN ISAAC.

A somewhat small aucl unpretentious exhibit was that made at the
St. Louis Exposition by the California State Commissioner of Horti-
culture, but it was one that attracted a great deal of attention, especially
among scientific men and the more intelligent class of orchardists and
farmers who visited that great exposition. This exhibit consisted of a
very complete and well-arranged collection of the various insect friends
to which California owes so much of her prosperity, and which are ever
and continuously working in our interest. Many of these insects are
exceedingly minute, so much so as to be practically out of the range of
the naked eye. To overcome this difficulty they were displayed behind
magnifying glasses of sufficient power to enable them to be seen, while
descriptions of them and the work they are doing for our State were
made in plain language. The result of this has been a great deal of
inquiry from Eastern sources as to our beneficial insects and our Cali-
fornia method of fighting bugs with bugs. To answer these inquiries,
as well as to give our own people a wider knowledge of what our insect
friends are doing for us, the following pages have been prepared.

Bfelow is a list of the different insects exhibited at the St. Louis
Exposition by this Commission:

PREDACEOUS COCCINELLIDyE.

Beneficial Insects. ITost Insects.

Vedalia cardinalis Cottony Cushion Scale (Icerya purchasi).

Novius koebelei Cottony Cushion Scale (Icerya purchasi).

Novius bellus Cottony Cushion Scale (Tcerya purchasi).

Vedalia sp. (black). Cottony Cushion Scale (Icerya purchasi).

Rhizobius ventralis ..Black Scale (Saisseta oleoe).

Rhizobius ventralis, larvae- _. Black Scale (Saisseta olese).

Orcus australasia Black Scale (Saisseta oleoe).

Orcus chalybeus Yellow Scale (Chrysomphalus [Aspidiotus] citrinus).

Rhizobius toowoombte. ... San Jose" Scale (Aspidiotus perniciosus).

Scymnus vagaiis Red Spider (Tetranychus telarius).

Rhizobius debilis ... Various scale insects.

Cryptolsemus montrouzieri ._ Mealy Bugs (Pseudococcus [Dactylopius] sp.).

Hyperaspis lateralis 1 Cypress Mealy Bugs (Pseudococcus ryani).

Exochomus pilatii Various scale insects.

Chilocorus bivulnerus.-. San Jos6 Scale (Aspidiotus perniciosus), and others.

Coccinella sanguinea Various scales and aphids.

Coccinella calif ornica Various aphids.

Coccinellu abdominalis ..Various aphids.

Coccinella oculata Various aphids.

Hippodamia ambigua Various aphids.

Hippodamia convergens Various aphids.

04

4 CALIFORNIA STATE HORTICULTURAL COMMISSION.

PARASITIC HYMENOPTERA, DIPTERA, ETC.

Beneficial Insects. Host Insects,

Scutellista cyanea Black Scale (Saisseta olese).

Dilophogaster californica Black Scale (Saisseta olese).

Hymencyrtus crawii ... Black Scale (Saisseta olese).

Aphelinus mytilaspidis Black Scale (Saisseta olese).

Aphelinus fuscipennis San Jose" Scale (Aspidiotus perniciosus).

Aspidiotophagus citrinus Yellow Scale (Chrysomphalus [Aspidiotus] citriiius) and

San Jose" Scale (Aspidiotus perniciosus).

Pteroraalus puparum Internal parasite of the Cabbage Butterfly (Pieris rapse).

Gorays fusca Brown Apricot Scale (Eulecanium armeniacum).

Encyrtus flavus Soft Brown Scale (Lecanium [CoccusJ hesperidum).

Coccophagus lecani Soft Brown Scale (Lecanium [Coccus] hesperidum).

Coccophoctonus sp Yellow and Red scales.

Eupelmus mirabilis Internal parasite of the Katydid (Microceiitrumretinervis).

Braconidsp Parasite of Cutworm.

Anastatus sp - Egg parasite of Tent Caterpillar.

Tachnia fly Internal parasite of Cabbage Butterfly (Pieris rapte).

_ Internal parasite of Lecanium robinarum.

Aphelinus sp. Internal parasite of Aphis.

Somewhere about the year 1868, a California nurseryman in San
Mateo County, not far from San Francisco, imported some lemon trees
from Australia. There was nothing unusual about this, nor was there
apparently anything unusual on the trees themselves; nevertheless
that importation cost the State of California millions of dollars and
came near destroying one of the most important of its fruit industries,
for on those trees, unseen and unnoticed by any one, were some of the
young of the now well-known cottony cushion scale (Icerya purchasi) .
These soon reached their mature stage, and still no notice was taken of
them; they were regarded merely as a curious object when noticed, and
it was never dreamed that they were the commencement of one of the
most terrible pests that California fruit-growers have ever known. The
insects increased in numbers, but not being in a fruit section, and their
depredations being confined largely to ornamental stuff, they were dis-
regarded. Soon afterwards a Los Angeles nurseryman and florist
secured some of the imported stock, with the imported pest, and so it
was introduced into Southern California. Here conditions were better
suited to it than even in the section where it had first obtained a foot-
ing in the State, and it spread much more rapidly. Soon it got into
the orange orchards. Here conditions seemed perfect, and in a very
short time it had spread to an alarming extent. Orchards in which it
had become firmly established were covered with it until they looked
as though they had been exposed to a severe snowstorm. It was soon
found in remote sections, and in a short time appeared to have taken
possession of the whole country. Nor did it confine itself to the orange
trees; many varieties of fruit and a great quantity of ornamental
plants fell beneath its attacks. It even found its way to forest trees,
and for some time it looked as though it would reduce the whole country

BUG VS. BUG. O

to a desert. Orange-growers were in despair. From eight thousand
carloads, shipments dropped to six hundred in one year. Every pos-
sible remedy was tried, but none was found effective, and even the most
costly served only to temporarily check the spread of the pest. Orange-
growers were digging out and burning their trees to get rid of the pest,
but even this did not avail, for had all the orhards been destroyed there
was sufficient wild stuff to keep it spreading.

In 1888 the National Government made an appropriation for the
purpose of advancing the American interests at the Melbourne Expo-
sition, and the appointment of the late Hon. Frank McCoppin as
chairman of the commission to forward said interests was the nucleus
of California's first effort in the search for natural enemies of orchard
pests. McCoppin 's friends in the orange district where this pest had
caused such terrible losses urged that he should do something to save
the orange industry. Correspondence was opened with the Hon.
Thomas F. Bayard, Secretary of State, and through him, with the
Department of Agriculture and the Entomological Division of that
Department. This resulted in the sending of Albert Koebele, who dis-
covered the Vedalia cardinalis, with the commission. While there were
„ others in the State who were convinced of the parasitic theory and
enthusiastic in their efforts to bring about the investigation, there was no
available money until the above opportunity presented itself.

This discovery of a small ladybird known as the Vedalia cardinalis
started California on her present course of fighting bugs with bugs, and
no doubt this will continue until every insect pest that disturbs plant
life and its fruits will be overcome by natural insect enemies, even if it
should require traversing the very ends of the earth.

It is to be hoped that other states, and the National Government, will
take up this work and thereby save hundreds of millions of dollars' loss
that is now borne by the cultivators of the soil.

This ladybird was collected and forwarded to California and dis-
tributed all over the State wherever the scale had made its appearance.

Nearly, if not quite, all of the injurious pests of any section are intro-
duced species, and in every case they have been introduced without their
checks, for in its native habitat every pest, in fact every form of life,
has some other form of life which preys upon it and prevents it from
becoming redundant. Now, when any such form is removed to a new
section, where it has no natural enemies, there is nothing to stop its
unlimited spread, and as insects propagate more rapidly than any
other form of animal life, without some check they would 'soon overrun
everything within reach. These checks are usually other insects, and
they are divided into two general classes— the predaceous class, or those
which devour their prey from the outside, the most important among
which is the great ladybird family, and the parasitic class, or those which

6 CALIFORNIA STATE HORTICULTURAL COMMISSION.

work in or on the body of their host. These latter are often microscopic,
or very nearly microscopic, in size, but are among the most effective of
our insect friends.

Usually each predaceous or parasitic insect attacks but one kind of
insect ; each has its own particular form of food and will touch no other.
The Vedalia, for instance, lives wholly upon the cottony cushion scale,
and if it can not get this, it will starve before it will touch any other
form of food; so that, in searching for the enemies of onr destructive
insects, it is necessary to find just the right one.

It is a fact well known to all entomologists, that in their native homes,
while insects are sometimes very troublesome, and in some sections exist
in unusual numbers, they never become the serious pests that they do
when they are removed to a new country where their checks do not exist.
Usually in their native homes they are rather rare than otherwise. So
when it is known that any pest is especially severe in any section, as, for
instance, the San Jose scale (Aspidiotus perniciosus) over a great part
of the Eastern States, it is very certain that it has been introduced there,
and in order to find its check, we must find its native home, where it is
scarce, and then we must find what agency is keeping it down. Some-
times our native parasites will adapt themselves to the introduced
species, as has been the case in California with the San Jose scale. This
pest was as great a terror to our growers some twenty years ago as it now
is over a great part of the Eastern States ; but one of our native parasites,
the Aphelinus fuscipennis, adapted its taste to it, and finding in the San
Jose scale a suitable food supply, it increased with almost unprecedented
rapidity until it overtook the scale, and to-day this scale is no longer a
pest in the California orchards. It is true that it occasionally makes its
appearance in remote sections, but never to any dangerous extent, and
the little parasite soon overtakes it and reduces it below the danger line.
So little regard is paid to the San Jose scale in California now, that we
never recommend any action against it. Spraying is still carried on,
but this is more for the purpose of keeping the trees clean and healthy
'than for the purpose of getting rid of the San Jose scale. Before this
parasite did such effective work, California orchardists were having very
much the same experience that their Eastern brethren are having now,
and trees by thousands were dug out and destroyed in order to get rid
of the scale. It is to be hoped that the days of this terrible pest in the
Eastern orchards are numbered, for it has been discovered that the same
parasite which has freed the California orchards is now at work there,
and in a report made by Prof. W. G. Johnson, when entomologist of
Maryland, he says:

Since we assumed charge of the State work in Maryland, we have collected the S:m
JosA 'scale on various food plants and inclosed infested twigs, about four inches in
length, in glass cylinder tubes, open at both ends ; the ends were closed with cotton, and
if any parasites existed upon the scale, they were easily detected and mounted for

BUG VS. BUG. 7

study. Only upon rare occasions have we taken more than a half-dozen specimens
from a single tube. This experience has been repeated year after year until the fall
of 1899. * * * Last fall, however, I discovered a new locality for Aphelinus
fuscipcnms, near Easton, Talbot County, in an infested orchard along the Miles
River. The orchard contained a miscellaneous variety of fruits, and all the trees
were quite seriously infested with ,tfee San Jose scale. Instructions have been given
the owner to cut them down as soon as possible and burn them. A quantity of small
branches infested with scale were brought to the laboratory and inclosed in breeding
tubes. Much to my surprise, these tubes were swarming with parasites a few days
later. Prom one tube 3,114 specimens of ApheUnufi fuscipennis were taken, while
a second tube gave 432, a third 1,478, and a fourth more than 1,000, but owing to
an accident the count in the case last mentioned was not exact.

The California method of fighting insect pests is to use the most
efficient artificial means while we have to, and to this end we apply all
sorts of known washes, dips, and fumigation, but, while so doing, we
realize that these measures are very cumbersome, costly and inefficient,
and that nature has provided a better way, and it is of this way that we
avail ourselves. We endeavor to trace back the course traveled over by
our destructive pests, to trail them to their native lair, and there we
will find their check. This check, whether it be a parasitic or a preda-
ceous insect, or both, as sometimes found, we secure, introduce, and
breed, with the greatest care, in our insectary, where it becomes accli-
mated in its new home, and as it propagates it is sent into those sections
where the pest upon which it is to prey is most prevalent. This method
has been found so effective that we have now very few -really trouble-
some orchard pests, the worst at the present time being the codling-
moth, and for this we hope to find a natural check, and are now working
toward that end.

It must not be supposed from this that there are no insect pests in
California. We have been importing these pests from all parts of the
world for half a century past and have had representatives from all
parts of the world, and have them still, for when an insect once obtains a
foothold, its eradication is practically impossible, but by introducing its
natural enemy, we offset one against the other, and give ourselves no
further uneasiness as to the outcome. The pests may do some damage,
they may break out in sections in unusual numbers for a time, but
invariably they are reduced below the line of serious damage shortly
by the natural means, and it is done more effectively and permanently
than can be done by any artificial method.

In an address before the fourteenth annual meeting of the Association
of Economic Entomologists, Prof. C. L. Marlatt gave an account of a trip
he had made to Japan and China in search of the native home of the
San Jose scale, and in speaking" of its discovery there he alluded to para-
sites which he found working upon it, and which are the same species
which have done such good work on this pest in California. He said:

The apple industry of Japan is of recent origin, say within the last thirty years ;
most of the stock has been obtained from California, and as a rule was more or less

EXPLANATION OF PLATE I.

Fig. 1. Novius koebelei, Olliff ; Koebele's ladybird. Male; enlarged,
la. Novius koebelei. Male ; natural size.
1&. Novius koebelei. Female; natural size.
Ic. Novius koebelei. Larva ; enlarged.

2. "Black Vedalia." Enlarged.

3. Novius bellus. Beautiful ladybird; enlarged.

4. Novius (Vedalia) cardinalis, Mulsant; Australian ladybird;
4a. Novius (Vedalia) cardinalis. Natural size.

4&. Novius (Vedalia) cardinalis. Larva ; enlarged.

5. Lestophonus icerya. Dipterous parasite of the cottony cushion

scale; enlarged.
5a. Lestophonus icerya. Natural size.

6. Ophilosia crawfordi. Hymenopterous parasite of the cottony

cushion scale; enlarged.
6a. Ophilosia crawfordi. Natural size.

7. Twig infested with cottony cushion scale ; natural size.
la. Icerya purchasi crawii, Cockerell.

7b. Icerya purchasi inaskelli.

CALIFORNIA STATE COMMISSION
OF HORTICULTURE.

PLATE

BUG VS BUG.

THE BENEFICIAL IPi

THAT SAVED THE
CITRUS FRUIT INDUSTRY" OF CALIFORNIA.

BUG VS. BUG.

infested with San Jose scale when received. Throughout this region the San Jos6
scale was found scatteringly in all orchards and in all gardens. In Aomori and
vicinity it is doing no very great damage in any of the orchards, but in some of the
small gardens and especially in one or two neglected ones in the city of Aomori, it
was as abundant on particular trees as it often is in America. At the first investi-
gation no evidence of parasitism was seen, but from later collections two of the
parasites which attack the scale insect in America were raised in great numbers from
infested branches collected at Aomori. These as determined by Dr. Howard are
Aphelinux fuscipennis, How., and Aspidiotophagus citrinus, Craw, the latter being
the more numerous.

This latter parasite is the true internal parasite of the Japanese
yellow orange scale. The San Jose scale is not a native of Japan, so it
is evident that this little parasite adapts itself to the introduced variety,
which is a near relative of the yellow scale upon which it is generally
found.

So effective has this work of introducing beneficial insects and encour-
aging native parasites been, that we have practically reduced all the
worst of our scale pests and very many other destructive insects below
the danger line. Among the many beneficial insects which are now at
work in our State, and the pests which they are at work upon, and most
of which they keep in control, we name the following :

COCClNELLIDjE.

Vedalia eardinalis, Mulsant. (Plate I, Figs. 4, 4r/, 4/>.) This is
commonly known as the "Australian ladybird," from the fact that it
was imported from Australia in order to work upon the cottony cushion
scale (Icerya purchasi, Maskell). As stated above, this pest had
obtained such a foothold in our orange orchards that the citrus industry
of California was threatened. The fact that the cottony cushion scale
came from Australia, where it was not a pest, was sufficient proof that
there was some very efficient check at Avork upon it there, and investiga-
tion by Albert Koebele discovered this little beetle. The ora.nge-growers
of Los Angeles County, especially, had a very expensive experience with
this scale. As it had spread into the wild bushes and trees, extermina-
tion by artificial means was out of the question. Now the scale is no
longer a pest. When it appears in an orchard the owner is supplied
with a colony of Vedalia. During the summer the transformations of
this iadybird are very rapid. From the egg, through the larva and
chrysalis, to the perfect beetle, takes only twenty-one days. Of course,
the larvae are the most active feeders. When short of feed, the larvae
will attack each other, but no matter how hungry they are they will not
eat any other species than the cottony cushion scale. This ladybird
breeds throughout the year.

Novius koebelei, Olliff (Koebele's ladybird). (Plate I, Figs. 1,- la,
16, Ic.) This is another effective enemy of the cottony cushion scale
2 — BII

10 CALIFORNIA STATE HORTICULTURAL COMMISSION.

and does as good work as the Vedalia. The latter, however, was first
introduced, and its reputation became so great that all others were over-
shadowed by it. The Novius koebelei, however, has proved itself equally
as prolific and quite as voracious a devourer of the cottony cushion
scale as its companion. This ladybird is also an introduced species,
having been sent from Australia for the State Board of Horticulture
by Mr. Koebele ori his second trip to that country.

The illustrations give a good idea of this beautiful and active little
ladybird. It feeds upon the cottony cushion scale (leery a purcJtasi),
searching out the solitary scales even better than the Vedalia. It passes
through its different stages in about the same time as the latter.

FIG. 1. Xovius koebelei, male, enlarged. FIG. 2. Novius koebelei, female, enlarged.

Novius bellus (Beautiful ladybird). (Plate I, Fig. 3.) This is also
an Australian species, having been introduced into California from that
country by Mr. George Compere. It is one of the several coccinellid
enemies of the cottony cushion scale, and has done very excellent work
upon that pest. It has been generally distributed over the State.

Vedalia sp. (Plate I, Fig. 2.) This is an unnamed species of Veda Ha.
from its color commonly known as the "Black Vedalia." It is also an
Australian species, introduced by the State Board of Horticulture
through Mr. George Compere, and is another of the coccinellids which
prey upon the cottony cushion scale.

Rhizobius ventralis (Black ladybird). (Plate IV, Figs. 3, 3o, ?,b.)
This is also an Australian ladybird, introduced by the State Board of
Horticulture through Mr. Koebele, and is one of the natural enemies of
the black scale (Saisseta [Lecanium] oleae) . This ladybird was intro-
duced for work on the black scale, and was generally distributed by
the State Board of Horticulture wherever that pest was found. It was
one of the most promising of the many importations of beneficial insects
and took hold of its work with a vigor that gave promise of soon extir-
pating one of the worst of the California scale insects. Wherever it was
introduced in the coast counties of the State, it increased with wonderful

BUG VS. BUG.

11

rapidity and the scale as rapidly disappeared, and in those sections it
still continues to do good work, but efforts to establish it in the interior
counties have not met with as good success, the heat probably being too
intense for the young larva?. This insect, however, is well established
all over the State, and in many sections is as abundant as any of our
native species. Wherever it is abundant, it is a chief factor in keeping
in check the destructive black scale.

Oreus australasia, Boisd. (Six-spotted blue ladybird). (Fig. 3.)
This is one of the most beautiful of the introduced species. Like most

OHCUS AUSTRALASIA. Boisd 'magnified!; la. Ditto-natural i
£ Pupa enveloped in larval skin; 2a. Ditto (natural i
3 I.arva: 3a. Ditto (natural sizei.

FIG. 3. Oreus australasia.

of the latter, it is a native of Australia, and was imported from that
country by the State Board of Horticulture through Mr. Koebele. It is
an enemy of the black scale (Saisseta [Lecanium] oleae) , and is now
well established in many parts of California, especially in the coast
counties. The female is nearly one fourth of an inch in length, deep
blue in color, with six orange red spots on the wing-covers. The male
is similarly marked, but is a smaller insect. This species is a more
general feeder than 0. chalybeus. In Santa Barbara w

•tflkMt ..*

County it is bred on black scale, and in Alameda on the
pernicious scale. It loves the sunshine, and is found
more numerous toward the top and the outside branches
of the trees in which it is established. The larva and
pupa resemble the same stages of Pilate's ladybird.

Oreus ehalybeus, Boisd. (Steel-blue ladybird). (Fig.
4.) So named from its brilliant steel-blue color, which
makes it a conspicuous object wherever it is found. This
ladybird 'preys largely upon the yellow scale (Clirysom-
plialus [Aspidiotus] citrinus, Coquillett), and also upon beus, enlarge!* *
the red scale (Clirysomplialus [Aspidiotus] aurantii, Maskell), which
it consumes in great quantities. This was introduced into California

EXPLANATION OF PLATE II.

Fig. 1. Encyrtus flavus, Howard. Enlarged,
la. Encyrtus flavus. Natural size.

2. Coccophagus lecani, Howard. Enlarged.
2a. Coccophagus lecani. Natural size.

3. Comys fusca, Howard. Enlarged.
3a. Comys fusca. Natural size.

4. Soft brown scale (Coccus [Lecanium] liesperidum, Linn.).

On orange leaf.

5. Brown apricot scale (Eulecanium [Lecanium] armeniacuw,

Craw). On prune twig.

6. Brown apricot scale, showing exit holes of Comys fusca.

CALIFORNIA STATE COMMISSION
OF HORTICULTURE.

PLATE II

BUG VS BUG.

THE INTERT1AL, PARASITES THAT HOLD I IN! CHECK

THE "SOFT BR.OWM SCALE" AND THE
"BROWN APRICOT SCALE" IN CAI.IFORMIA

CALIPO?

Bl'G V£

by the State Board of Horticulture some years ago and is now found
established in many parts of the State.

Rhizobius (toowoombse) lopantha. (Plate III, Fig. (>.) This little
ladybird was formerly described under the name of Scymnus margini-
collis, but is identical with Rhizobius lopantha. Mr. Koebele sent this
beetle about the same time that he introduced the Vedalia, but it was
found in the State previous to that. However, it has only been within
the past few years that its value has been observed. It breeds from
early spring until late in the fall. As compared with the beetles the
larvae are very large, they are light colored, with a lighter oblong square
on center of the back, and remain a long time in the larval stage, feed-
ing voraciously. When about to change to the chrysalis, they hide
away under cobwebs, dry leaves, and other debris. The beetle is
metallic black, with a brown thorax. They feed on Aspidiotus perni-
ciosus, Chrysomphalus (Aspidiotus) aurantii, Chrysomphalus (Aspidio-
tus) citrinus. Aspidiotus hederae (nerii), and occasionally on aphis.
In San Diego County it is proving effective on purple scale (Lepidosa-
phes beckii) . In alluding to the excellent work of this little beetle on
the purple scale in the above named county, Mr. Allen, of Bonita.
writes :

With us the largest hatch of purple scale has usually been in May. So far this
year I have not seen a single instance of purple scale hatching, nor can I find any
live scale in an orchard adjoining us, every tree of which a year ago was literally
alive with them. Since last July this orchard has been to iny knowledge thoroughly
stocked with the Scymnus, though when they first entered it I can not say. As they
undoubtedly came in large numbers their work has been rapid.

I sprayed only a small part of the ranch last summer, and there can be no question
but that, except for the work of this parasite, our place would be teeming with the
purple scale, whereas I have yet to see the first live one, and our fruit, from trees
that used to be infested, is now coming off the tree clean. I believe this ladybird is
also eating the yellow scale, because there is so much less of it on the fruit, but of
this I am not yet sure.

By September the efficiency of the purple scale parasite should be thoroughly estab-
lished, for if any live eggs are left they must hatch before that time ; yet even now it
seems to me that the work of the Scymnus is second only to that of the Vcdalin, and,
considering the difference of the scales and the fact that the purple is so heavily
armored, its work seems even more remarkable.

Seymnus vagans. This is one of the smallest of the ladybird
family-, but not one of the least important. It is an enemy of the red
spider pest which is very general all over the world, and especially
detrimental to almonds, prunes, and citrus trees. The long, dry seasons
of California are favorable to the spread of this pest, which flourishes
under arid conditions, and which has been especially troublesome here.

This little ladybird was introduced from Australia by Mr. George
Compere for the State Board of Horticulture. It was found to be very
effective in checking the spread of the pest, and has been generally
established in California.

CALIFORNIA STATE HORTICULTURAL COMMISSION.

Rhizobius debelis. This is another one of the introduced species of
ladybirds which we OAve to Australia. It is a scale-feeder and has been
very generally distributed in the State.

Cryptolsemus montrouzeri. (Fig. 5.) This is another of the Austra-
lian coccinellidae. It is the natural enemy
of the mealy bug (Pseudococcus [Dactylo-
pius] ) . It has been introduced into the
Hawaiian Islands, where this pest was HO
bad in the coffee plantations as to almost
threaten the total destruction of the crop,
and it has done such good work that the
pest has been practically cleaned out. Suc-
cessful efforts have also been made to estab-
lish it in the coffee plantations of Central
America, where the mealy bug has also ap-
peared in destructive numbers.

FIG. .">. Cryptolsemus montrouzeri,
enlarged.

Hyperaspis lateralis, Mulsant. This is one of our native ladybirds
and is very generally distributed over the State. It is a small, black
ladybird, with two reddish-yellow spots on the elytra, near the apex,
two spots on the disc, and two blotches of the same color on the for-
ward lateral margins. Forehead and edge of thorax yellow. Feeds on
pernicious scale in the adult form. Cypress trees (Cupressus macro-
carpa) in the suburbs of San Francisco that were seriously infested
with the cypress mealy bug (Pseudococcus [Dactylopius] ryani) were
cleared of the pest by this ladybird. The larvae of this species are
covered with a cottony secretion and resemble mealy bugs.

Exoehomus pilati, Mulsant. (Fig. 6.) This is another of our very
common native ladybirds. It resembles in
general appearance the twice-stabbed lady-
bird (Chilocorus [bivulnerus] fraternus),
but is much larger. It also differs from the
latter in having the under side of the ex-
tremity of the abdomen black, instead of red.
The larvae resemble the twice-stabbed, but
are larger and lighter-colored. Both the
larva and beetle feed upon young black scale, but they do not increase
very rapidly.

Chiloeopus (bivulnerus) fraternus (Twice-stabbed ladybird). (Plate
III, Figs. 3, 3a.) This is one of our most important native ladybirds.
The larvae are most voracious, and destroy great numbers of young
black, pernicious, and other scales. The young are long and covered

FIG.

BUG VS. BUG. 15

with dark spines, crossed with a yellowish band near the middle.
When about to change, into the pupa or chrysalis, the larva selects the
under side of the large branches, where it attaches itself with a gummy
substance to the bark, head downward. In a few days the spiny, larval
skin splits longitudinally, exposing the inclosed chrysalis. When the
beetle issues from the chrysalis it has a black head, with white wing-
covers; in a short time this changes to a shiny black, with a red spot
on each elytra. In this stage it also preys upon scale insects.

Coeeinella sanguinea, Linn. (Blood-red ladybird). This is a medium-
sized native species, found very generally distributed over California.
It feeds upon aphids and young scale insects, but is not so common as
some of the other species, and is not, therefore, so beneficial. The
beetle is of a solid color, varying in intensity from a dull red to a bright
scarlet.

Coceinella ealiforniea, Mann. This species is a very common one in
this State, and the beetles are sometimes found in enormous numbers.
They are very social in their habits, and can sometimes be found in
such numbers as to be gathered by quarts. They are larger than the
sanguinea. The elytra are orange-red, without spots or markings;
thorax is black, with a light spot on each side. They feed principally
on aphids. Like other species of ladybirds, the larvge do the most good.

Coecinella abdominalis, Say. This is known as the "ashy gray
ladybird," from its prevailing color. This ladybird is hemispherical in
form, ashy gray in color; with seven small black spots on the thorax
and eight on each wing-cover. It is said to be one form of Coceinella
oculata, Say. It is an aphis-feeder, and where it exists in quantity does
good work.

Coceinella oeulata, Say (Eyed ladybird). This, while it is supposed
to be one form of the preceding, does not resemble it in any manner, in
its markings or general appearance. The adult insect is deep black in
color, with two distinct orange-red spots on the wing-covers, and might
easily be mistaken for Chilocorus f rat emus. There is a distinct differ-
ence in these two insects in the markings of the thorax, the oculata
being light yellow on the under side and around the margin of the
thorax. Like its other form, abdominalis, it is an aphis-feeder, and a
very effective one where it is found ; but in this form it is not a common
insect in this State.

Hippodamia eonvergens, Guer. This is another of the common
ladybirds of California, and is found throughout the State during the
summer months very plentifully, among corn and other vegetables.
The larvae feed upon aphids and other insects, while the mature insects

EXPLANATION OF PLATE III.

Fig. 1. Aspidiotophagus citrinus. Craw. Enlarged,

la. Aspidiotophagus citrinus. Natural size.

2. Aphelinus fuscipennis, Howard. Enlarged.

2a. Aphelinus fuscipennis. Natural size.

. 3. Chilocorus bivulnerus; " twice-stabbed ladybird. " Natural size.

3a. Chilocorus bivulnerus. Larva. Natural size.

4. San Jose scale (Aspiodiotus perniciosus, Comstock). Natural

size. On pear twig.

5. Yellow scale (Aspidiotus citrinus, Coquillett). Natural size.

On orange leaf.

6. Rhizobius (toowoombae) lopantha. Natural size.

CALIFORNIA STATE COMMISSION
OF HORTICULTURE.

PLATE 1

BUG VS BUG.

THE FOUR SPECIES OF INSECTS THAT SUBDUED TH

'SAN *JOSE SCALE" AND "YELLOW SCALE"

IN CALIFORNIA.

BUG Vfc. BUG. 17

also feed upon aphids, young scale, etc. The beetles vary somewhat in
color; some are of a deep red, while others are of a dull brown, the
markings, however, being uniform. Sometimes after ripe fruit has been
punctured by birds or other agencies, the beetles of this species will be
found upon it, sipping the moisture, and on this account they have been
thought sometimes to be injurious. They are, however, among the most
important of our insect friends.

Hippodamia ambigua, Le Conte. (Figs. 7, 8, 9.) This is a very
abundant native species. The adult beetle resembles the blood-red
ladybird somewhat, but is narrower in proportion to its length, and
flatter. It is distributed over the whole State, and is often found in
great numbers. It is an aphis enemy, and does excellent work on the
plum, apple, and woolly aphis. During the later fall months these
insects may often be found in sheltered places in great masses, in
which condition they hibernate during the colder months.

PIG. 7. Hippodamia ainbigua. FIG. 8. Hippodamia ambigua, FIG. 9. Hippodamia ambigua,
enlarged. pupa. larva.

HYMENOPTERA.

Seutellista eyanea, Motsch. (Plate IV, Figs. 1, la, 16, Ic.) This
is comparatively a new introduction into our State, having been secured
from South Africa, where it was found to be a very effective worker on
the black^ scale (Saisseta oleae) . In the short time it has been estab-
lished among us, it has done most remarkable work, and, so far, promises
to be as efficient a check for the black scale as the Vedalia has been on
the cottony cushion scale. Of its introduction, Mr. Craw writes :

It was not until Prof-. Charles P. L/ounsbury, Government Entomologist of Cape
Colony, called attention to the Seutellista eyanea as an efficient enemy of the black
scale in that country, that its true value was recognized.

Through the efforts of the Hon. S. F. Leib, of San Jose, and Mr. Ed. M. Ehrhorn,
of Mountain View, Senator Perkins appealed to the United States Department of
Agriculture to use its good offices toward securing this valuable insect. Several
colonies were forwarded to Mr. Ehrhorn, but, unfortunately, without any practical
results from either sending. On October 1, 1901, Professor Lounsbury wrote me :

"By to-morrow's boat we start you two boxes containing cuttings of oleander
bearing parasitized scale. It is not ideal material by any means, and this is not the
season we most wish to send in, but the scale and its parasites are both so scarce
that we must send what we find as soon as we find it. Most of the scale in your

18

CALIFORNIA STATE HOBHCUI7TURAL COMMISSION.

vicinity will be old by the time this reaches you. but I am in hopes that you may be
able to get material from the south of the State that will take a generation of the
parasite. Owing to the probable presence of secondary parasites, it is, of course,
inadvisable to send the original material to any orchardist down there."

From this sending, seventeen perfect insects developed, of which four were females.
When placed in a breeding case, a small spider that was hidden in a rolled-up leaf
seized and killed one of the females, leaving us but three from which to colonize the
State.

On December 26, 1901, I examined a full-grown black scale from the tree in the
breeding case, and found a small maggot of the $cutellista cyanca, about twice the
size of a black scale egg. This convinced me that they were breeding, so no further
examination was made. On February 7, 1902, the parasites began to issue from the
scales. During the warm summer months we found that the Scutellista passed
through all its metamorphoses in forty-seven days.

Colonies have been sent to all the counties of the State where black scale has been
troublesome. From personal examination and from material sent in, it is evident
that the parasites have obtained a good start, and the coming season will, we hope,
see them thoroughly disseminated.

Description: In the female, the antenna; are reddish-brown, with
the ring joints and hips dark and more spreading than in the male.
The antennae of the male are black from the ring joints to and including

FIG. 10. Tomocera californica, male, greatly
enlarged.

FIG. 11. Tomocera californica, female, greatly
enlarged.

the clubs, with the scape reddish-brown ; the legs in both sexes are black,
tarsi reddish-brown, and claws black; the scutellum in both male and
female is very large. As the flies are small and very active, it is diffi-
cult to detect them on the tree upon which they may be placed, and the
best way to determine if they are established, is to 'remove and examine
the inside of the full-grown scales about forty to forty-five days after
liberating the parasites. The larva is maggot-shaped and white, this
soon changing to the pupa, which is black just before changing to the
perfect fly.

Tomoeera (Dilophogaster) ealiforniea, Howard. (Figs. 10, 11). This
is one of our native internal parasites. In has been one of the most
effective checks of the black scale in the State, but was not able to keep

BUG VS. BUG. 19

this pest wholly under control. In a report on scale insects and their
parasites, Professor Comstock says of this insect :

This is one of the most interesting parasites, both structurally and economically,
which we have discussed in this paper. It lives upon the destructive black scale, and
so abundant is it in certain regions that upon more than one tree at least seventy-five
per cent of the scales appeared to be parasitized. In no locality was the black scale
found without this attendant destroyer.

The female parasite pierces the body of the female bark-louse and deposits probably
but a single egg. At all events but a single parasitic larva has ever been found upon
a single scale. The larva of the parasite feeds upon the eggs and the young of the
Lecanium, and, also, later upon the mother herself. When full grown it is about 0.15
inch long, broad, spindle-shaped, somewhat more pointed at the anterior than at the
posterior end of the body. Its color is clear white, the contents of the alimentary
canal, however, often showing through and giving it a blackish tinge. This larva
transforms to a whitish pupa, which soon turns black. The adult parasite makes
its exit through a round hole which it cuts in the back of the scale.

Hymeneyptus erawii, Aslimead. This is an Australian insect, and
is one of the very effective internal parasites of the black scale in that
country. It was introduced into California by Mr. George Compere,
and has been reported as doing very good work in the districts where it
has become established.

Aspidiotophagus eitrinus, Craw. (Plate III, Figs. 1 , la. See Fig. 12.)
The internal parasite of the yel-
low scale (Chrysomphalus [As-
pidiotus] eitrinus) and the £>an
Jose scale (Aspidiotus pernici-
os-us). The former scale was at
one time as great a source of
trouble to the orange-growers of
southern California as the red
scale (Chrysomphalus

aurantU) is nOW. It fairly FKJ. 12. Aspidiotophagus citrinus, greatly

enlarged.

covered the citrus trees, reduced

the quantity of fruit, and destroyed its quality. Every effort was made
by artificial means to resist its attacks, but these were unavailing.
Finally it was discovered that there was some natural check at work,
and investigation discovered this little internal parasite. Instructions
were at once given to the orange-growers to stop spraying for the yellow
scale and to give this little friend a chance to increase. This advice
Avas followed, and in a very short time the yellow scale disappeared
from that section and it has not since been regarded as a pest, although
no other means have been taken to check it. Mr. Craw has bred this
parasite from yellow scale upon imported trees from Japan. Mr. Mar-
latt bred it in numbers from San Jose scale in Japan. It is also one of
our best cheeks for the same scale in California.

EXPLANATION OF PLATE IV.

Fig. 1. Scutellista cyanea. Motsch. Female : enlarged,
la. Scutellista cyanea. Natural size.
Ib. Scutellista cyanea. Larva; natural size.

2. Scutellista cyanea. Male; enlarged.

3. Rhizobius ventralis, Blackburn. Black ladybird ; enlarged.
3a. Rhizobius ventralis. Natural size.

3b. Rhizobius ventralis. Larva; enlarged.

4. "Black Scale" (Saisseta [Lecanium] oleae, Bern). On orange

twig.

5. "Black Smut"; fungus, existing on exudation of black scale.

6. "Black Scale," showing exit holes of Scutellista cyanea.

CALIFORNIA STATE COMMISSION
OF HORTICULTURE.

PLATE IV

BUG VS BUG.

THE TRUE PARASITE AND ENEMY
OF THE

"BLACK. SCALE.

OF THE A

( UNIVERSITY 1

OF

BUG VS. BUG. 21

Aphelinus fuseipennis, Howard. (Plate III, Figs. 2, 2a.) It is well
within the memory of the fruit-growers of California when the San Jose
scale was the most terrible of our pests. It antedated the appearance of
the cottony cushion scale and attacked nearly all of our deciduous fruit
trees. For some time it seemed as though the fruit industry of our State
was doomed, at least such varieties as were attacked by this pest, and
orchardists were digging out and destroying their trees by thousands in
order to stay its ravages. Various compounds were devised to fight it ;
among them the now celebrated wash of salt, sulphur, and lime was dis-
covered as most effective. This wash is still the best known artificial
remedy for San Jose and kindred scales on deciduous trees; but it is
impossible with the greatest care to destroy any kind of pest by artificial
means. There are always solitary trees which will be neglected, careless
people who refuse to spray, wild shrubbery out of reach of the operators,
and all of these become sources of infection. While active and efficient
work was being done by artificial means against this pest, it was discov-
ered to be disappearing in sections where no spraying was done, and
investigation showed that one of our native parasites, the Aphelinus fus-
eipennis , had adapted its taste to it and was rapidly getting it under.
To-day, wherever the San Jose scale is found we also find its parasite,
and while the pest has not, and never will disappear, it is entirely con-
trolled by its little enemy until we pay no further attention to it.
Spraying is still carried on, however, as it has been found beneficial to
our fruit trees in killing other pests, preventing fungous diseases,
and keeping the trees healthy; but so far as the San Jose scale is con-
cerned, there is no further need of artificial remedies.

This same parasite is generally distributed all over the United States
and is undoubtedly doing good work, as shown in our quotation from
Prof. W. G. Johnson of Maryland, but the long winters and compara-
tively short summers there may check its spread. In the mild winters
and long summers of California it probably has more broods than there,
and, increasing in greater quantity, it is enabled to do more effective work.

Pteromalus puparum. This is a very common enemy of the cabbage
butterfly (Picris rapae) in this State, and undoubtedly to its work is
due the fact that this pest is not more common than it is. This parasite
has a. wide range and is found over the greater part of the United States.
It is parasitic upon the pupa of the butterfly, upon which it lays a
number of its eggs, which, hatching out in its unfortunate victim, puts
an end to its career. Prof. F. M. Webster in "Insect Life" gives an
interesting account of the operations of this insect, as follows :

On the morning of August 9th, we observed a larva of I'ieris protodice, Boisd., in
the act of transformation to the chrysalis. Near by, and very evidently watching this
transformation, were a male and female of this parasite. The trio were observed
several times during the early part of the day, the parasites always on guard, as it

22 CALIFORNIA STATE HORTICULTURAL COMMISSION.

were, although the females several times were observed to attempt oviposition, in
ever.v case, however, being deterred from so doing by the jerking of the larva, now in
a semi-pupal state. During one of these visits the male was- driven away, but soon
returned. About 6 P. M., the last observation of the day, the transformation of the
larva, while not complete, had so far advanced as to prevent the radical movements
which had characterized its struggles during the forenoon, and the female was busily
engaged in her work of oviposition, the male still present as a spectator (?i. On
the morning of the 10th, the chrysalis, now fully developed, was removed and placed
in a glass jar, awaiting further developments. On the morning of the 27th, seventeen
days after, the adult Ptcromalus were observed issuing from the chrysalis in great
numbers. After all had emerged, • they were counted and found to number us males
and 4 females. The same parasite had been reared from a similar chrysalis on
August 13th, but the individuals were not counted.

Corny s fusea, Howard. (Plate II, Figs. 3, 3a.) This is one of the
most effective of the scale parasites in our State. Its efforts are princi-
pally directed to keeping down the brown apricot scale (Eulecanium
[Lecanium] armeniaciUH, Craw) , and wherever it has become thoroughly
established it has accomplished this object in very good style. The
brown apricot scale has been one of the most serious scale pests of the
State, frequently covering the twigs of apricot, plum, and prune trees
with an almost solid incrustation, destroying the vitality of the trees,
ruining the fruit, and doing incalculable damage. By means of this
little internal parasite, however, we are enabled to keep the pest well
under control, and whenever there is an outbreak of the scale, colonies
of the parasite are sent and soon become established. The parasites are
small, and their capture and shipment require great care. The method
in which this is done is by noting an orchard in which the insects are
well established the preceding season. From this orchard large quan-
tities of infested twigs are secured about the middle of May, or before
the parasites begin to emerge from the scale. These are carefully
trimmed of all leaves to prevent mildewing, and then placed in square,
wooden receptacles or boxes, as shown in the illustration (Plate VIII).
These boxes are bored with a number of half -inch holes in the upper
half and all light elsewhere excluded. Into these holes small vials are
fitted, with the mouths inward. The insects, as they emerge from the
scales, seek the light and enter the vials placed to receive them, and
when there are enough in any one to form a colony of sufficient size,
usually from twenty-five insects up, the vial is removed, stopped with
a little cotton wool to prevent their escape and yet admit air, another
vial is set, and the process is repeated. The vials are then carefully
packed in stiff paper tubes (see Plate IX) and mailed to all sections
where there have been any reports of outbreaks of the scale. In this
manner, beneficial insects are distributed by tens of thousands all over
the State and nature is aided in her efforts to keep our insect enemies
within proper limits.

Eneyrtus flavus, Howard. (Plate II, Figs. 1, la.) This is one of
several internal parasites of the soft brown scale (Coccus [Lecanium]

BUG VS. BUG. 23

hesperidum) . This scale was another of the very serious pests which the
orange-growers of California had to contend with and from which they
have been relieved by insect aids. When orange-growing was in its
infancy, the soft brown scale obtained a foothold in the orchards, and
without any check soon spread. In a short time the trees were covered
with it and were suffering greatly from its depredations. In a compara-
tively short time, however, it began to disappear, and investigation
showed that several internal parasites, among which the Encyrtus flaws
was one of the raoSt important, were actively at work upon it. and
reducing it below the danger limit.

Coeeophagus lecani. (Plate II, Figs. 2, 2«.) This is another of the
internal parasites of the soft brown scale (Coccus hesperidum). It is
found in several of the Lecaniums, but its best work in this State has
been on the soft brown scale of the orange, which, in connection with
Encyrtus flavus, it has kept below the danger limit.

Coeeophoetonus sp. This is an internal parasite of both the yellow
and red scales, and while it has not done as extensive work as some of
the other parasites above described, it is none the less an important
addition to our list of friendly insects.

Eupelmus mirabilis, Walsh. This is an egg parasite of the katydid
(Microcentrim retinervis, Scudder). The female insect lays her eggs
within those of the katydid. The young parasite is hatched and at
once proceeds to eat the eggs of the host insect. The Eupelmus mirabilis
has been an invaluable friend to the orchardists of California and
especially to those engaged in orange-growing, where at one time the
katydid was an annoying and destructive pest. It is now rather a rare
insect in those sections where it was once so common, and it is difficult
to find its eggs without observing that they have been perforated and
destroyed by this parasite.

Besides the above-named insects which are common in California,
and to which without doubt we owe our position as a fruit-producing
State, there are a number of others of greater or less importance, among
them a species of Braconid, parasitic on cutworms ; Anastatus, an egg'
parasite of the tent caterpillar, and another parasite of the tent cater-
pillar eggs. There is also a Tachnid fly which destroys the cabbage
butterfly by laying its eggs on the victim, the young larva hatched
from which eats up the caterpillar and destroys it. There is also an
internal parasite of the Eulecanium (LecaniUm) robinarum, Douglas,
and a species of Aphelinus working as an internal parasite of the aphis.

24

CALIFORNIA STATE HORTICULTURAL COMMISSION.

DIPTEROUS INSECTS.

In the great family of dipterous or two-winged flies, we find very
many of our worst pests ; among them the many fruit flies, which do so
much damage by laying their eggs in the ripening fruit, and which
hatching out into a mass of crawling maggots render it wholly unfit for
use; but at the same time this order gives us very many of our best
friends, and prominent among them are the following :

Lestopihqnus ieerya. (Plate
I, Figs. 5, 5<z; also Fig. 13.)
This is an exceedingly small,
two-winged fly, which was
found at work on the cottony
cushion scale at Sidney, N.
•S. W., by Albert Koebele.
It is now thoroughly estab-
lished all over California
wherever the cottony cushion
scale is found, and has proved
itself a valuable auxiliary to
th"1 Vcclalia cardinalis in keep-
ing that pest in check.

FIG. 13. Lestophonus ieerya, enlarged.

Celatoria erawii, Coquillett. (Fig. 14.) This is another of our
beneficial flies, being an internal parasite of the well-known twelve-
spotted squash beetle, so common in fruit-growing districts, and is one

Larva.

•*&'< it *&&'*'
^^Bl^^

Female, enlarged.

FIG. 14. Celatoria orauii, Coq.uillett.

Pupa.

of the rare instances that have been recorded of a beetle being destroyed
by the larvae of a fly. It is not only interesting to an entomologist, but is
of great assistance to the horticulturist in reducing the numbers of such
a serious pest. Mr. Craw discovered this parasite in the neighborhood

BUG VS. BUG. 25

of Los Angeles, where he collected a large number of the beetles, and
found that fully one third were parasitized. He found them in the
larval state in the beetles as early as May and as late as the middle of
October. The May brood pupate early in June and remain in this con-
dition about two weeks, when they change to the winged form. They
are numerous in July and August.

Masicera paehytyli, Sk. (Fig. 15.) This is one of the Tachnid flies,
the whole of which family are parasitic on other insects. They are of
medium size generally, and
to a casual observer resemble
our common house flies. The
favorite food of the greater
part of the members of the
family are the caterpillars.
The female lays her eggs on
the soft bodies of the caterpil-
lars and the young grubs de-
vour their host, which never
attains its mature state. It *'

is tO this family that the re- FIG ]5 Masicera pachytyH, Sk. parasite of

duction of moths and butter- the locust,

flies below the danger limit

is due. The one of which we give an illustration in Fig. 15 is parasitic
on the locust, and unquestionably does much toward keeping this terrible
pest in check in Australia, where it is native. This is one of the intro-
duced species and has been established in our State. Mr. A. H. Bray
gives his observations on this insect, as follows :

The grub, or larva, is found within the locust, where it appears to live upon the
adipose tissues of the victim, avoiding the vital parts with unfailing instinct. The
grub lives indifferently in the thoracic region or the abdomen of the locust, and
frequently three or four may be found in a single grasshopper.

The grubs leave their victims when they are full grown, usually by means of an
opening which they eat in tb.e side of the locust at the point where the abdomen joins
the metathorax ; but they do not invariably make their exit from' the body of the
unwilling host at that particular place, as on one occasion I observed two grubs
escaping from a grasshopper at the same time — one from between the first and
second abdominal segments, and the other from between the head and prothorax. As
soon as the grub makes its escape, the grasshopper, which has gradually grown more
and more feeble as the inclosed parasite has gained in size, dies. In several instances
I have observed that the grasshopper died before its enemy succeeded in making-
its escape ; and in one case a larva was seen vainly struggling to free itself from
between the metathorax and the abdomen of a dead grasshopper, where it. was
firmly held by the contracting remains of its victim. The grub, which subsequently
died without extricating itself, succeeded in freeing more than half its body, but it
was firmly held by the tail.

The Sypphidas, or syrphus flies (Figs. 16, 17, and 18), are another
large family of dipterous insects, many of which are beneficial to man.

26 CALIFORNIA STATE HORTICULTURAL COMMISSION.

They are usually very conspicuous from size, color, and markings, and
Tery many of them resemble other insects and may be mistaken for
bees, .wasps, etc. They are often seen in sunny weather poising almost
motionless on the wing, especially over flower-beds, occasionally darting
on their prey. The larva of the syrphus flies is of great benefit in
•destroying all kinds of aphids. It is quite blind, but the egg from which
it hatches is deposited by the parent fly in the midst of a colony of
plant aphids, where it gropes about and obtains an abundance of food
without much trouble. The larva is fleshy, thick and blunt behind, and
pointed in front. Its mouth is furnished with a triple-pointed dart,
with which it seizes and pierces its prey, and, elevating it as shown in
the figure, deliberately sucks it dry.

MAGNIFIED NATURALS.ZE

MAGNIFIED , NATURALS12E

FI<; Ifi. FIG. 17. FIG. 18.

Larva of Syrphus Fly. Pupa of Syrphus Fly. Syrphus Fly.

This is but a partial list of the very many insect friends which are
doing' so much for California horticulture, and which it has been the
policy of the State Board of Horticulture and the State Horticultural
Commissioner to foster and encourage to the widest extent, and at the
same time to add to their numbers all beneficial insects which can be
secured from any part of the world. To this end correspondence is car-
ried on with entomologists in different parts of the world, while agents
of this department are dispatched to discover and introduce beneficial
species wherever they can be found. It is the policy of this State to
use artificial remedies so long as there are no better ones, but to secure,
introduce, and distribute the better means, and these consist of beneficial
insects, as soon as possible. In California, at least, this plan has been
found a very effective and profitable one, for of all the many insect
pests which have been found here, and they are as numerous as any-
where on earth, and have been imported from all parts of the earth,
there are not now more than two or three really serious species, and all
are controlled by their insect checks, either native or introduced ; and
so far as those for which we have not yet found an effective parasite are
concerned, we are now searching for one, and* in view of our past suc-
cess in this line, will undoubtedly find it.

vo 'ooslo^avaJ NVS

u*j ';; Uofy
J3UOISSIIBW03

OF THE

UNIVERSITY

OF

*»

^
con

I U I DUOb

00