Boring caterpillars affecting corn and other crops and which are liable to be mistaken for the European corn borer [microform]

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/APPLIED IN/MGE Inc

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DOMINION OF CANADA

DEPARTMENT OF AGRICULTURE

ENTOMOLOGICAL BRANCH

C. OoaooM HiwiTT, DoMiMioK EnimtoLoatn.

BORING CATERPILLARS AFFECTING CORN

AND OTHER CROPS AND WHICH ARE

LIABLE TO BE MISTAKEN FOR

THE EUROPEAN CORN

BORER

ARTHUR GIBSON

Chief, Division of Field Crop and Garden Insects

CIRCULAR No. 14

[TECHNICAL]

Published by direction of the Hon. S. F. Tolmie. Minister of Agricultura,
Ottawa, Canada

632.70^1
C212

OTTAWA

J. m LJ> tOQl'ERIE TACHfi

PRINTER TO THE KIN; S MOST EXCELLENT MAJESTY

1920

iHued April 9, 1920.

lAiE SHALL BE PLEASED to hwir from anyone concerning
damage or tVouble of any kind due to intect pests. No
postage is required on any such letteis of enquiry when
addressed :

DOMINION ENTOMOLOGIST,

Department of Agriculture,

OTTAWA, ONT.

Such enquiries should be accompanied in all cases where it
is possible by specimens of the insects. The insects should be
sent packed with their food plant in a strong wooden or tin box
to prevent loss in transit. Packages up to 12 ouncos in weight
may be mailed free and every package should boar or contain
the sender's name and address and bp accompanied by a letter.

To the Honi)urul)l)>

Thr Minii«t<T of Agriculture,
Ottuwu, Ont.

Ottawa, February 18, l»20.

Sir.— I have the honour to HuWmit herewith for approval KntomoloKieal
Circular No. 14 (Teehnieal), entitle*!: "Boring ( aterpillurH Aflfeeting Corn ami
other CropH and which are Liable to he Mistaken for the Kuro|K'j;n Com Borer",
which has l)een prepared by Mr. Arthur (iilwon, Chief, Division of Field (Vop
and Garden Insects.

As a result of the efforts which we are making to prevent the introduction
and establishment in Canada of the European Ct)m Borer we have received
numerous boring caterpillars which have been mistaken for that insect. In view
of the fact that a numiM>r of the caterpillars are of economic importance, anci in
order to have available information concerning them, this circular has been
prepared for distribution as occasion may demand, and for the purpose of enabling
agricultural workers and others to distinguish between the various species of
caterpillars which may be found boring in corn and other croj <.

I have the honour to be, Sir,
Your obedient s<>rvant,

C. CORDON HKWITT,

Dominion Entomologist.

77237— U

WARNING

THE EUROPEAN CORN DORER

TM pMl HlMteCMI. WrtTNS, tm. raNU «M MMU CMPt

M4lMrM«MiylMlMMil««tolMMtMM

IKK B (UVE MWaKTlilHMOtlWWKWWi WW ■"»"«"■

HOW TO

RECOGNIZE rr

lolM in th« malkM ci tb*

ciwdpat'Uk* mittrlil iara-
ing from dMoa iadlart* th«
pn>aanofdMbonror

piltar. I0 tht cm of .

brokaa MSMla tlto show
Winn dM bonr Ib at work.

Uth* lahmi •MM wn
•pUt op«i tbt eatcrpillara
will Im found at work.
«• oft*n found just
•Imv* tlM roots.

The iuMct spends the
wintar ss a cstarpiikr in old
■talks uf com or other food
plants and changas to a
xeddi8li4wown pupa lata in
the spring. Tba pupa soon
turns into s moth.

Ifh.

M aarasaa ara arasslli ra^aaatad ts ksap a asastaat iaakaat fsr tMs

awat damraaa aaat aad ta rapart taaaadtalaiy sH saspMaas assas.
Mastad rfaats tsfaUisr witk tha laasato tiiaaMalvas slMaia hs forwardsd ta
thaMMIIM nmOLOMST. DVT. OT AMNCULTUK. OTTiWH. OIT.
Paaksgas awlsr twahra aaaaas la walgirt aiay ha saat fraa ofpastags.

r— iinmn

Boring Caterpillars Affecting Corn and other Crops

and which are Liable to be Mistaken for the

European Corn Borer.

By Akthi.h Gihhox,
Chief, Pivision of Fielil Crop and Garden Inserts.

IXTUODICTOUY.

Tlicn- art' a nuniluT of ilifferi'nt kinds of caterpillars which iMirc into ami
work insidv of the Htcmn of plants and which in 1911) attracted more than usual
attention in view of the warning jHwter relating to the F^uro|M-an corn l>orer,
Pifrtnmtn niibilaliH Hlin., which |H(ster was distributed widely l>y the
KntoinoloKical Branch in May last. Injury liy these horing caterpillars is
usually confined to a limited number of plants, hut occasionally the infestation
is of a serious nature. Their presence may usually be detected by the
unhealthy app«'arance of the plants, the toj)s of which in most instances bei mie
withered and fall down at one side.

THK KIHOPKAN COHX BOHKH, PyrnuMn ntibilalix Hbn.

The name European corn borer has been applied in<liscrin>inately v
farmers and gardeners generally to the various kinds of lutring caterpii irs
discussed in this circular. The European corn borer, however, is <iuite difTt , .nt.
Its work may be judged by the plate herewith which is a reduction of the i)<)ster
referred to and in which the insect is represented in its various stages of de-
velopment.

In view of the fact that thi.s insect nas, since 1917, established itself in
certain of the eastern United States, as for instance, in Massachusetts, New-
Hampshire, New York, :>nd Penn.sylvania, the Dominion Department of Agri-
culture established, on May 2t), 1919, a «|uarantine against the infested states,
which quarantine prohibits the importation of corn on the col), corn stalks,
pp cing, green sweet corn, etc. Inspectors have traced shii)ments of com from
the affected districts imported into Canada during the past two years, ("ertain
sections of outhem Ontario adjacent to infested districts in northern New York
State, hay been examined in an endeavour to find out if this notorious jwst
had been introduced. We are glad to state that so far the European corn borer
has not been found in ( "anada.

In acldition to wrn, the cittirpillarM rPMiily U'n\ on mHny «th«T pUntu »*inh
•« wliTV, »M'iin, iHH't, npinarh, p«itHtu, tomato, turnip, rliuUrh, duhlin, «hryi«n-
thfRiunii, Rlutlioluit, raRweiMl, hunlork, plgwi«Ml, rtc. All part* of rom, whlrh In
th«' m<M»t fttvourjnl Umh\ plant, arr attarktti, netpi the fihrouN nnttn. Thf
rnont NcriouH iiamaRc U raum-d to thi« utalki* ami rarn whirh thi> Uin-r iwrtially
or totally dwitroyn. D. J. ('affn«y' (•tati-n that th. Um-n Rfni>rally pnt«'r thf
ptalk at thi- upp<r end near thr Warn- of th«« taKwl ami at firnt tu.inrl upwanl.
The (lamaRf* ho wrakfnii the tawM'l ntalk that it hreakx ovi-r Ix-fon- the taiwi'l
maturpH, rpnultinR in io!«N of polkn and tlii> lack of normal ^rain formation on th«>
earn. After deNtroyinR the taiwel the Inirerx tunml «lownward through the
Ktalk, Kradually in«-reaninE the itiie of their tunneU aw they develop. The plate
herewith well illuMtrateii tlie damaRe rauM>d by thin Iwrer.

When mature the European rom Ijorer Ih alniut one inrh lonR. It in of n
liRht hrownidh or fle»»h rolour, mime MiierimenH i)eing tlarker than other*. The
head in dark hrowu. the thoraeie shield jmler Itrown, a* are aluo the tul)erele(i
on the iKxiy.

Mr. Carl Heinrirh, of the V. S. Hnreau cif RntomoloRy, ha* recently puW-
linhed* a piiwr on the Kurop^-an rorn Iwrer, Pyrau»ta nubilalin, and it* neure*t
American allie*, nameh I'yranMa ninaliei and PyrnuHta jtenitnlia. I^irvul un<l
pupal de*eription* are K»ven ;i* well a* a key to weparate the three *p«'iie* in
adult, pupal and larval ntage*. The la*t two nameil *iM'«'ie* are foumt in ( 'anada ;

B ^/^V'

<i( I'^mu'ltt nnhilaliii;

Fl« l— .\. Doni»l view at the head n>pHuk> of the wva
B. Dornal view of the hc»d r»p«ul<' of the larva
(After Heinrirh).

the former in the Unite*! State* ha* been "frequently fountl in corn a*«ociated
v.ith P. nubilalis for which it* larva is ea*ily mi*taken". Thi* latter fact is
strongly empha.sized by the statement made by Mr. Heinrich, namely: "There
seem* to be only one reliable character— (to separate P. ainnHei from P. nuhilaliK)
namely, the arrangement of the »et» and puncture of the anterior epicranial
group. In P. nuhHalx, A' is approximate to A', and A', A', un<l the puncture
Aa are in a stra'"" line or with the puncture po*tero-ventra(l of .\'. In P.
ainsUei A» is us uea. lO A' as to A' (or nearer), the three setie forming almost a
right angle with the puncture Aa lying postero-dorsad of A', the seta; A' and A'
and the puncture forming an obtu*e angle. There is some variation in the degree
of distance separating A' and A' in individual specimens and some asymmetry,
especially in P. nubilalig: but the character seems to hold, and it has been found
sufficiently constant through liirgc series to enable accurate determination of all
larvffi so far submitted for identification." Mr. Heinrich's drawings showing the
setal arrangement discussed are reproduced herewith.

T. .«<. Farmers Hull. l(Mtt.

Uour. Auric-. Researrh, Vol. XVIU, 3. 171, Nov. 1, 1919.

THK.BURD<H'K BOKKK, hipaiprtHU mlaitknirhi (Irt.

Thin lM>n>r i*, on the wh<il<>, thr »n«> whirh \n miHit fn-iiuriitly I'linipUiiifMl of
■H B ipir<l«>n ptmt, nmi (lurinn lUItt wm* thr rnliTpillnr whirh wuh mmtt ortfii mmU
to tin A* MitR poMtibly th«> Kuro|N>iin corn tHifi>r. It i^ n Ki>n«>rttl ftHnipr nn«l
althoURh found commoT!' in cHHtcm ('anmla in tiu' Mvtwt of biiniiM-k, owiiiK
to whirh wi' Kiivi> it thi common name of thi* huniiM'k iMtn-r, it liy no nii'iuiH

Vtu. t 'fh* Httnlork Hufpr, /'kpai/M'iiM raf«fi*nN-to (irt ; natunl •iai>. lUriKiMl)

ronfinei* itn nttention to imt ninnt, Iwing founil in ii gn-iil vuri«'ty of pluntH
havinK nucfulent otemK. In the Ottawa tliHtrict. in uildition to l»ur<loi'k, wi*
havp found the larva in thi* uti-mH of larkspur, nunflowrr, RoldcnRhiw, duhlia,
Joe-pyi' wwhI, hollyhork, meadow ru«', r«»M'. iriw. lily, htmwU-i'k, tomato, |M)tato,
thiMtip, ('al)iiaK<'< rhubarb and rorn, Wp ha p, aim*, onp ' -mi of thp larva
lM»rinR in the fruit of jpxwplM'rry. On onp o«'cin«ion (I' > thp larvip wprp
tt()ppially abundant at Ottawa, purtipulurly in burdork. i I i: nlNiut an hour'**
time, wp pollppt«'d nparly fifty i*iK>pimpnH.

Kio. 3. Stem o( larkxpur destroyed by the HurdiM-k
Burer. (Oriinnnl).

The burdock borer when mature is about 1} inches in lenRtii. In ueneir .,
it is a smooth, cylindrical, pale-brownish caterpillar with a whitish dorsal str' e
and a lateral band of the ? me colour, l)oth continuous, the latter al>out t\ .ce
the width of the former. The tubercles on the body are dark brown and on some

8

specimens conspicuous. The head is shiny, yellowish-brown, with a wide dark
brown or blackish band running from the ocelli to back of head. This band
when the segments are drawn together joins the blackish lower margin of the
thoracic shield. Thoracic shield, otherwise, similar in colour to the head. In
the earlier stages the ground colour of the larva is much darker, the pale longi-
tudinal markings consequently being more contrasting. Some adult examples
are almost wholly creamy-white in colour, with inconspicuous markings.

Injury by this borer, in some years, is observable in the middle of June.
More often, however, the work of the larva is not detected until July during
which month, as well as in early August, the withered tops of infested plants
may be apparent in gardens or fields. As a rule, only one larva is found in the
same plant. In the case of the burdock, however, two or even more, larvae may
be present. In cultivated plants, one individual, of course, is capable of cau!«ing
the plant to wilt and die. This is especially so when young com is attacked.

When the larva is full grown it usually pupates in the stem where it has
been feeding. In 1904, a pupa was found exposed V)ut attached to an outside
leaf of an iris plant, about two inches from the ground. The moth emerged
on September 4. The pupal stage of specimens collected in the Ottawa district
ranged from 30 to 39 days.

THE STALK BORER, Papaipema nitela Gn.

This well known borer which is some years seriously abundant in Illinois
and other northern states, has not been responsible for important losses in
Canada. In 1905, the larvse were present in Kent county, western Ontario, and
caused some injury in corn fields. In addition to corn, the borer was found in
potatoes, tomatoes, Canada thistle, elder, lamb's quarters, garden beans, rag-
weed, pigweed, sweet clover, as well as in the stems of flowerinji plants in gardens.
In 1912, Mr. H. F. Hudson, found a borer in corn at St. Ives, Ont. Unfortu-
nately no adult moths were reared by Mr. Hudson but it was assumed that the
species was P. nitela. From material received from Fargo, Ont., in 1905, the
adult was reared on September 6, the larva, in confinment having left the food
plant and entered the earth for pupation on August 2.

The stalk borer when mature is about 1 H ipches in length. It is, in general?
very similar to the burdock borer. Usually it may be separated by the fact
that the reddish-brown stigmatal band is absent on the first four abdominal
segments.

Like the burdock borer, too, it generally changes to the pupal state in the
stem in which it has been feeding.

THE POTATO-STEM BORER, Gortyna micacea Esp.

This European insect has, of recent years, developed into a pest of some
importance. Since it was first recorded in Canada in 1908, it has spread con-
siderably, particularly within the provinces of New Brunswick and Nova Scotia.
While it is known to have caused important damage under field conditions its
injuries have, as j-et, been practically confined to gardens.

While the potato is a favourite food plant, the caterpillar readily bores
in the stems of corn. In the Maritime Provinces it is also kno^vn to attack
rhubarb, beet, tomato, pumpkin, pods of garden peas, iris, lily and dahlia.
In addition, in Europe, the larva is known to tunnel in horse-tail, sedges, dock,
valerian, plantain, hollyhock, etc. In Nova Scotia, in 1917, young corn plants
had been destroyed by the end of the first week in July. In 1919, in the same
province, similar plants had been ruined by June 26.

9

I

The following description of the caterpillar was made from a specimen
received from Manone, N.S., in July, 1906.'

"Length, 32 mm. Head, rounded, chestnut-brown, shining, mouth parts
darker. Body: a dirty creamy colour, with a pinkish tinge on dorsum, except
at intersegmental folds. Thoracic shield pale brown, margined anteriorly with
dark brown. Tubercles pale brown, each with a single pale hair. Tubercle
iv on seventh abdominal segment is almost as large as the upper half of the
spiracle, the upper edge being slightly above the upper edge of the spiracle.
Spiracles black. Anal shield blackish. Dorsal vessel distinct. No markings
whatever on the body. Feet all pale. ' '

The decided pinkish or rosy tinge of the upperside of this borer is charac-
teristic, and in this differs from any of the other borers discussed in this circular.

t

Fig. 4. Young corn plants destroyed by the Potato-
stem Borer, d'orlyna micaaa Esp. (Original).

The full life-history of the insect in Canada is not, as yet, known. Prof.
W. H. Brittain, Entomologist, Department of Agriculture for Nova Scotia, has
found the eggs at Truro, N.S. in the end of August and in Septembev on^the
stems of couch grass, Agropyron repens. This grass was abundant in a rhubarb
plantation the plants of which had been very seriously injured by the borer.
He states* that although he only found the eggs on couch grass, they arc doubtless

•Rep. Ent. Soc. Ont. 1908, 49 (1909.)

•fir. 26, Prov. N.S., CoUei^ of .Xgric., Dec. 1917.

10

deposited on various we^ds. "They are very small pinkish-coloured eges,
faintly ribbed, and are laid loosely, sometimes in rather large numbers on the
stems partially surroundetl by the leaf sheath. The larvse hatch in June and
make their way to a suitable food plant where they liore a tiny entrance hole in
the stem, usually at the surface of the ground. They bore in the stem or in
the crown of the plant until some time in August and then enter the ground
where they transform to a pupa, emerging in late August or September as an
adult moth."

Since 1914, we have received many complaints of the work of the potato-
stem borer, the.se referring chiefly to injury to potatoes and corn. During 1919,
we recei/ed from Nova Scotia half-grown larvse in the middle of June. From
then until the end of July larva from the Maritime Provinces continued to arrive,
most of the specimens sent being thought to be the European com borer. In
Ontario, in 1905, larvte were found an late as Augu.st 31. Running through the
<lifferent years we have records of the emergence of the moths from August 6
(190«) to September 18, (1905). The pupal stage is about 19 days.

A WESTERN CORN BORER, Hdotropha reniformis atra Grt.

In June, 1919, we received at Ottawa larvse of a noctuid boring in corn-
Mr. Norman C'riddle, Entomologist, in charge of our field laboratory at Trees-
bank, Man., under tlate of June 22, forwarded a larva which he had received
from Winnipeg, Man., with the statement that it had been found in considerable
numbers attacking growing corn, first the leaves and later the stem into which it
bored. On June 23, we received a further communication, this time from Mr.
A. V. Mitchener, Lecturer in Horticulture, Manitoba Agricultural College,
Winnipeg, Man., which stated that the lar\;i had been found injuring corn
about a foot high. Further, that "the larva cuts a hole in the outside of the
stalk and bores its way up into the centre." The injured plants had been
detecte<l from their wilting and consequent drooping. About June 18, Mr.
Mitchener visited the infested corn fields immediately north of the city of
Winnipeg and found several affected plants. The owner of the field reported
that previous to Mr. Mitchener's visit he had seen considerable injury. Several
other fields were similarly infested.

Mr. ('riddle also reported that injury to corn by apparentlj- the same
caterpillar had taken place at Virden, Man., which is close to the western
boundary o' Manitoba.

The following description was made from a larva received from Mr.
Mitchener:

Length extended IJ inches. Head yellowish-brown; ocelli black; man-
dibles reddish-brown. Thoracic shield concolorous with head, margined
rather widely anteriorly with brown and thinly with same colour posteriorly
and laterally. Body flesh-coloured with a faint indication of a pale brownish
ground colour and continuous pale whitish dorsal and lateral stripes. Tubercles
brown, i and ii round, of similar size; iii slightly larger than ii; iv and v close to
spiracle, the former about four times the size of iii and / about the size of iii but
elongate in shape; vi and vii similar in size and about twice the size of v. Anal
plate yellowish-white margined rather widely with brown anteriorly; narrowly
edged with brown posteriorly.

Apparently little is known of the early stages of Helotropha reniformis atra
Clrt. to which this larva is supposed to belong. The only previous record of
injury to corn by the caterpillar of this moth is a short note by A. J. Cook' which

Ann. Rep. (1887-1888) Sw. State Bd. Agr., Mich., p. 1611.

u

states that the larva, during two waHons, had heen destruetive to corn in some
localities in Michigan. The caterpillar was described as being "grey in colour
and striped with dark lines".

In Manitoba, in 1919, the Iwrer was referred to by Mr. ('riddle as the " Wes-
tern com borer". Unfortunately he was not able to rear any of the moths of
Helotrof}ha reniformis atra Ort. but reported that they were rather abundant in
Manitoba in the latter part of July. This fact along with other evidence
strengthens our supposition that the larva described above belongs to this mt.di.
The larva which he forwarded to Ottawa is somewhat different from the one
described above, being younger, and more whitish in colour. The probability is,
however, that it belongs to the same species

A NEW EASTERN CORN BORER, Ajmrnea niditana americana Speyer.

On July 14, 1919, we received from Mr. A. W. McDonald, of Pictou, N.S.
two larvsp, both of which had been found boring in corn. The following descrip-
tion was made from one of the specimens: —

Length 31 mm. (U inches), colour <lull greenish-grey, with conspicuous,
wide, subdorsal band of dull pale re.", and a thin lateral stripe of the same
colour. Tubercles black, i and ii of similar size, iii larger than ii, iv very large
immediately behind the spiracle, v smaller and elongate in shape, vi and v.i
about same size as iii. Ventral surface paler than dorsal and lateral areas.
Head yellowish-brown. Cervical shield pale brown margined with i)lack. Anal
shield pale brown.

This noctuid larva in confinement pupated about July 19 in the earth near
the corn plant at a depth of one-half inch, and the moth emerged on August 1,
1919.

Both the larvae received had eaten the centre of the young corn plants and
their work in general was noted to be similar to that of the potato-stem borer,
Gortyna micacea Esp.

In England the caterpillar of Apnmea nidlUints Borkh., the moth of which is
known as the ear moth, is recorded as feeding upon the roots of gras.ses in May.

The above is the only breeding record we have of .4. iiictitarix americana
Speyer.

THE CORN EAR-WORM, Hellothii^ obsokta Fab.

During 1919, this insect was more than usually abundant in Manitoba,
Ontario and Quebec. In August and September, even as late as (October It),
ears of corn infested by the caterpillars were received, with the supposition that
the "worm" was the European corn-liorer. In its younger stages it is known to
bore into the bud and feed upon the tender leaves as they unfold.

The corn ear-worm has not as yet caused serious losses in Canada. One
of the most important records of injurv which we have refers to an outbreak
which occurred in 1898 in the district of Orillia, Ont.; the report received stated
that the larva" had been verv destructive injuring as much as 95 per cent of the
ears of both sweet corn and yellow fieltl corn. This caterpillar has ajso been
found in Canada, boring into the fruit of growing tomatoes.

12

When mature, the com ear-worm is from about one and one-quarter to one
and one-half inches in length. It varies in colour from a light green to dark
brown, with rather indistinct strips on the back and a witier, conspicuous, pale-
coloured band along the side. The head is of a yellowish-brown colour. In the
darker coloured examples the dorsal stripe i s brownish divided in the centre by a
thin whitish line. The stigmatal band is wide, mostly cream-coloured, mottled

Fro. _. . „„„,

HeUolkit obMltia Fab.

. 8. Earof cornshowins the work of the Corn ear-worm,
Photo by W. Robinson (Original).

with pink, the lateral area immediately above being brownish. The rather,

wun pmK, tne lateral area immediately above being brownish. The rather,
"""•st'nct, additional, thin, longitudinal striping of the whole upper surface of
the body and the numerous short spines which cover the skin readily separates
this caterpillar from other corn-feeding species.

THE SPINDLE- WORM, ^c/iflWes 2eae Harr.

The lan'a of this insect known as the Spindle-worm is some years not
uncommon in Ontario and Quebec provinces. In the United States it is known
to bore in the stems of corn, but we have no record of it causing injury to this
plant in Canada. In the Ottawa district we have found the larvae rather plentiful
in some seasons, boring in the young shoots of elder, Sambucus. In 1901, we
reared a number of the moths, the date of issue being July 6.

\xru '^^^ caterpillar is unlike any of the other borers discussed in these pages.
When mature it is about one inch long. In colour it is yellowish-white with
conspicuous blackish-brown tubercles. On the abdominal segments tubercle
i is round and almost twice the .size of ii which is elongate; iii, iv and v are close
to and about the same distance from the spiracle; iii is about the same size as ii
but rounded; iv behind the spiracle rather .smaller than iii; v immediately in
front of and about half the size of the spiracle which is jet black; vi about the
size of i but not rounded; vii smaller than vi and more elongate. Head black,
thoracic and anal plates blackish-brown; the latter bear six conspicuous cone-
like protuberances.

.b

18

THE GLASSY CUTWORM, Sidetnia devastator Brace.

This well known cutworm which feeds upon the roots and lower stems of
various kinds of grasses, has some years been responsible for serious injury in
com fields. In June, 1918, Mr. H. F. Hudson and I investigated an outbreak in a
com field, near Strathroy, Ont. The larvae were present in noticeable numbers
and had destroyed many plants. This larva is not, of course, a borer, but owing
to the fact that it commonly injures com, its work may be mistaken for that of
the European com borer; in fact individuals were receive<l in 1919 as being
possibly this latter borer.

The glassy cutworm is of a dirty-whitish colour, with a greenish tinge.
The head is reddish or reddish brown, the shield on the first segment being con-
spicuous and brownish. The only markings on the body are the dull brown
tubercles, each of which bears a single hair. The front feet are pule brownish,
the hind ones being of the same colour as the Ijody. Full grown specimens arc
about an inch and a half in length.

Fio. 6. Young parsnip plant showing work

of the Parsnip Webworm, Depreanaria

herttcliana De G. (Original).

THE PARSNIP WEBWORM, Depressaria heracliana De Geer.

This well known pest of parsnips has also been received as being possibly the
European com borer. It owes its common name to the habit of webbing the

14

inflorescence or flowering part of the plant. The parsnip webwonn doe« not
feed on com, hut confines its attention to umbelliferous plants such as the wild
and cultivated parsnips feeding upon the forming seeds and leaves of the flower-
heads, and later upon the whitish lining of the hollow utems of the plant, into
which it burrows and where it pupates. The illustration, herewith, shows
typical injury to young parsnips.

When full grown this larva is about two-thirds of an inch in length. In
colour, it is yellowish or greenish-ycMow with conspicuous blackish tulwrcles of
similar sixe on each segment. The head is jet black ; the thoracic shield blackish ;
the spiracles small, round and jet black. Thoracic feet blackisi Anal shield
yellowish-brown.

The pupal stage is about three weeks. We have reared the moths from the
last week of July until the middle of August. The winter is passed in the adult
stage.

CULTU. . PRACTICES ASSIST IN THE CONTROL OF BORING

CATERPILLARS.

Insects such as the borers cannot be reached by outside applications of
spray material. When a valuable garden plant is found to be infested it may l)e
possible to locate and remove the borer by cutting a slit in the side of the stem.
Tomato and other thick stemmed plants have frequently been saved by this
method, thread or light string being afterwards tied around the stem where the
slit was made. Usually, however, it is a wise procedure to remove all weakened
stems which indicate the presence of a borer.

Clean culture is the main preventive measure in the control of boring
caterpillars. It is known that the adults of some of the borers deposit their eggs
on weeds, and very often important injury to plants is effected near the edges
of fields and gardens close to which weeds of various kinds have been allowed to
grow. It is important, therefore, that weeds of all kinds should be kept down
as much as is possible, throughout the entire growing season. Remnants of
crops, old stems of garden plants and weeds, should be removed regularly and
burned.

IMPORTANT TO IDENTIFY BORERS FOUND IN PLANTS.

In view of the close resemblance of the European corn borer to its nearest
allies, and also generally, to other borers when in their younger stages, it is urged
that farmers and gardeners report at once the presence of any borer found in
plants, particularly if in corn, such reports to be sent to the nearest Entomolo-
gical Laboratory, Provincial Entomologist, or Dominion Entomologist. Pack-
ages containing the caterpillars and their work, up to 12 ounces in weight, may
be mailed to Ottawa, without postage, if addressed

Dominion Entomologist,

Department of Agriculture,
Ottawa, Ont.