Papers on cereal and forage insects

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Title:
Papers on cereal and forage insects
Series Title:
Bulletin / U.S. Dept. of Agriculture, Bureau of Entomology ;
Physical Description:
7 v. : ill. ; 23 cm.
Language:
English
Creator:
United States -- Bureau of Entomology
Publisher:
U.S. Dept. of Agriculture, Bureau of Entomology
Place of Publication:
Washington, D.C
Publication Date:

Subjects

Subjects / Keywords:
Forage plants -- Diseases and pests   ( lcsh )
Grain -- Diseases and pests   ( lcsh )
Genre:
federal government publication   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )

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Bibliography:
Includes bibliographical references and index.

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Source Institution:
University of Florida
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
aleph - 029637351
oclc - 22577538
Classification:
lcc - SB818 .B85 no.95, 1913
System ID:
AA00018926:00003

Full Text
.7


, (/go o,


U. S. DEPARTMENT


OF AGRICULTURE,


BUREAU OF ENTOMOLOGY-BULLETIN No. 95, Part II.
L. 0. HOWARD, Enlomologist and Chief of Bureau.

PAPERS ON CEREAL AND FORAGE INSECTS.


THE


MAI


z


E


BILLBUG.


E. 0. G. KELLY,
Entomological Assistant.


j
ISSUED APRIL 22, 1911. '


WASH


INGTON:
INGTON:


GOVERNMENT PRINTING OFFICE.


1911.






















BUREAU 01' O EXTOMIOLOGY.

IL. 0. HOWARD, Entomologist and Chief of Bureau.
C. IL. MARLATT, Entomologist and A.cting Chief in Absence of Chief.
R. S. CLIFTON, Executive Assistant.
1V. F. TASTET, Chief Clerk.

F. n. CHITTENDEN, in charge of truck crop and stored product insect investigations.
A. D. HOPKINS, ih charge of forest insect investigations.
IN. D. HUNTER, in charge of southern field crop insect investigations.
F. M. WEBSTER, in charge of cercal.and forage insect investigations.
A. L. QUAINTANCE, iil (clirg/c of decidvlo 1." fruit insect investigations.
E. F. PHILLIPS, in charge of bee culture.
D). M. ROGERS, in charge of prerentlig spread of moths, field work.
IROLLA P. CURRIE, in charge of editorial iwork.
MABEL COLCORD, librarian.

CEREAL AND FORAGE INSECT INVESTIGATIONS.

F. M. WEBSTER, in chaIrge.

CEO. I. REEVES, C. N. AINSLIE, J. A. HYSLOP, T. D. URBAHNS, W. R. WALTON,
W. J. PHILLIPS, E. 0. G. KELLY, GEO. G. AINSLIE. PHILIP LUGINBILL, entomo-
ind experts.
W. J. PHILLIPS, E. 0. G. KELLY. GEO. G. AINSLIE, PHILIP LUGINBILL, entomo-
logical assistants.
NETTIE S. KLOPFER. preparator.















CONTENTS.

Page.
Introduction ............................................................- 11
H history of the species .................................................... 12
Injuries since 1895 ...... --------------------------------------------------- 14
Distribution .............. -------------------------------------------------------- 15
F ood plants ................... .... ....................................... 15
Description and life history. ....................... -------------------------------------------- ...... 16
N um ber of generations ................................................. .. 22-
Records of depredations ...........................................----........ 22
Rem edial m measures ....................................................... 22





I L L U STRAT 1 I () N S.


PLATES.
Page.
PLATE II. Fig. 1.-Corn plant injured by the adult of the maize billbug
(Sphenophorus mnaidis); afterward attacked by the larva. Fig. 2.-
Corn plant showing on stalk the effects of feeding by adult maize
billbugs; effects of feeding by larvae on roots. Fig. 3.-Corn plant,
much distorted, showing suckers; final effects of feeding of adult
maize billbug......... .............. ............. .... ....... ...... 18
III. Corn plants showing effects of feeding of adult maize billbugs in the
field; plant at left not attacked; the two at right attacked byv larvae. 18

TEXT FIGURES.

FIG. 5. The maize billbug (Sphenophorus maidisi: Eggs-...................... 16
6. The maize billbug: Larva .. .. ................................... 16
7. Corn plant showing result of attack by the maize billbug----............. 18
8. Swamp grass attacked by the maize billbug....................--.....- 18
9. The maize billbug: Pupa .....---------------------............-------......--..---------.. 19
10. The maize billbug: Adult......................................... 21
79236-Bull. 95-11 I





I
.7'
diii















U. S. D. A., B. E. Bul. 95. Part II. C. F. I. I.. April 22, 1911.

PAPERS ON CEREAL AND FORAGE INSECTS.


THE MAIZE BILLBUG.

(Sphenopihorus ma idis Chittn.)

By E. 0. G. KELLY.
Entomological Assistant.

INTRODUCTION.

There are several species of the genus Sphenophorus that have been
reported as being enemies to young corn in early spring. Heretofore
these reports have always been made in connection with fields of
grass, timothy sod, or lands recently reclaimed by drainage, and the
depredations were on the first cultivated crop following these
conditions.
Dr. S. A. Forbes a records eight species of Sphenophorus the adults
of which are known to attack young corn. Dr. C. V. Riley, in the
report of the Commissioner of Agriculture for 1881 and 1882, records
Dr. L. 0. Howard's observations on the habits and natural history
of S. robustus and gives a description of the imago, larva, and pupa,
Dr. Howard having found and reared these from specimens taken
from young corn plants at Columbia, S. C. Dr. F. H. Chittenden,
however, in a paper entitled On the species of Sphenophorus related
to pertinax Oliv., with descriptions of other forms," with refer-
ence to S. robustus, says:
This species ranges from Indiana and Michigan through Wisconsin, Minne-
sota, and western Kansas to California. It is a northern form, not occurring in
the East. Nothing appears to be known of its habits, reference to robitstfus
and its injuries to corn being due to a distinct species, my S. inaidi.s.
Dr. Chittenden had before him, while describing S. mnaidis, among
numerous other specimens, the one specimen from Columbia. S. C..
reared by Dr. Howard. According to his statement nmaidis is a valid
species and quite distinct from S. robustus.


a Twenty-third Report of the State Entomologist of Illinois, 1905.
b Proc. Ent. Soc. Wash., vol. 7, p. 57, 1905.





PAPERS ON CEREAL AND FORAGE INSECTS.


Dr. Chittenden informs the writer that since 1895 complaints have 4
been made every few years in localities in Kansas, South Carolinat, -
Georgia, and Alabama of injuries to corn by what he believes to be I
this species of billbug. The species has been quite generally confused :
with Sphenophorus pertinax Oliv. and S. robustus Horn, by both of
which names it has been mentioned in economic literature, more I
especially by the latter. It is, however, quite distinct from either,
in fact, different from any billbug known to inhabit the United
States, and has only recently been described as new to science, although
Dr. Chittenden states that it is by no means new as an agricultural foe.
The observations on the maize billbug (Sphenophorus maidia
Chttn.) given herein were made by the writer between June and
December, 1910.
HISTORY OF THE SPECIES.

The history of this species, the writer is informed by Dr. Chitten-
den, is, in brief, that it first attracted attention in Alabama as early
as in 1854; again in the same State in 1880; in South Carolina in
1881; in Kansas in 1895; in 1901 it again did injury in Kansas, and
in 1903 in Georgia. The fact that the insect is injurious to corn in
both of the active stages, larva and beetle, indicates that it is a
more or less permanent pest, whereas several of our equally common
corn billbugs will eventually disappear with the reclamation by
draining and the cultivation of the soil and the consequent destruc-
tion of their breeding places.
In the opinion of Dr. Chittenden, this is the species described and
figured by Townend Glover in 1855a as the "billbug" or 'corn borer
(Sphenophorus ?)," since both description and figure do not apply
to any other billbug known to breed in corn. Glover describes the
beetle as from four-tenths to six-tenths of an inch in length, and of
a reddish-brown or reddish-black color, and the rostrum or snout
in the figure can not belong to any other Sphenophorus. None of
the specimens which served as models of the drawing remains in the
Government collections. The billbug was reported as very destruc-
tive to corn in many parts of the South and Southwest, more par-
ticulariy along the Pedee River. Injuries were reported by Senator
Evans, Gen. Fitzpatrick, and Col. Pitchlynn. Senator Evans's
report is as follows:
The perfect insect eats into the stalk of the corn, either below or just at
the surface of the ground, where it deposits its egg. After changing into a i
grub, the insect remains in the stalk, devouring the substance, until it trans-
forms into the pupa state, which occurs in the same cavity in the stalk occi- ;
pied by the grub. It makes its appearance the following spring in the perfect i
state, again to deposit its eggs at the foot of the young corn plants. These
aAgricutltulral Report of the P'atent Office for 1S54 (1855), p. 67, pl. 4.


12







THE MAIZE BILLBUG.


insects destroy the main stem, or shoots, thus causing suckers to spring up), which
usually produce no grain, or, if any, of very inferior quality to that of the
general yield. Swamp lands or low grounds are the places most generally
attacked.
Senator Evans thus is, according to Chittenden, to be credited
with the discovery that the larva develops in the stalk of corn below
the ground, and not in decaying wood, as contended by Messrs.
Walsh and Riley in later years. The insect was said to be very
destructive in Alabama, from which State the specimens chosen for
illustration doubtless came, and on the Red River in Arkansas.
With little doubt it was the same insect operating in Arkansas, as it
is now known that this species ranges between South Carolina and
Missouri.
This insect was observed in the spring of 1881 by Dr. L. 0.
Howard, at that time assistant to Dr. C. V. Riley, Entomologist of
the Department of Agriculture. Dr. Howard was at once sent to
Columbia. S. C., to investigate the injury being done to corn by
6 billbugs," and the following account of these investigations is
taken from the report of his observations:"a
The species found near Columbia, S. C., is S. robustus [now S. maidis]. In
the plantations along the bottom lands of the Congaree River much damage is
done by the adult beetle every year. and the corn not infrequently has to be
replanted several times, as the earlier plantings are destroyed. The beetles
are first noticed in the spring after the corn is well up. Stationing themselves
at the base of the stalk, and also burrowing utinder the surface of the earth
slightly, they pierce the stalk and kill many plants outright, others living to
grow up stunted and dwarfed.
With S. sculptilis [zct], in spite of the damage it has done, the earlier stages
remain unknown, Walsh surmising that the larva breeds on rotten wood, so
situated that it is continually washed by water. With this statement in my
mind I was prepared to doubt the statement of Mr. W. P. Spigener, of Columbia,
who informed me that the "grub form of the billbug" was to be found in the
corn, but a couple of hours in the field convinced me that he was right, my
previous idea having been that he had mistaken the larva of Chilo sacclharalis
for the weevil grub. I searched a field on Mr. Spigener's plantation, which was
said to be the worst point in the whole neighborhood for bugs, for some time
before finding a trace of the beetle in any stage, but at last, in a deformed
stalk, I found in a large burrow, about at the surface of the ground, a full-
grown larva. After I had learned to recognize the peculiar appearance of the
infested stalks I was enabled to collect the larvae quite rapidly.
They were present at this date (Aug. 20) in all stages of larval development,
but far more abundantly as full-grown larvre. A few were preserved in alcohol
and the remainder forwarded alive to the department, but all died on the way.
Two pupae were found at the same time; one was preserved in alcohol and the
other forwarded to the department. The beetle issued on the way, and from
this specimen we have been able to determine the species. From an examination
of a large number of injured stalks it seems evident that the egg is laid in the
a Report of the Entomologist, Department of Agriculture, for 1tS1 and 1882,
pp. 139-140.


13





14 PAPERS ON CEREAL AND FORAGE INSECTS. i
stalk just at the surface of the ground, preferably and occasionally a little :
below. The young larvae, hatching, work usually downward, and may be found
at almost any age in that part of the stalk frow which the roots are given out.
A few specimens were found which had worked upward for a few inches into l
the first section of the stalk above ground, but these were all very large indi-
viduals. and I conclude that the larva only bores into the stalk propet-after I
having consumed all available pith below ground.
The pupae were both found in cavities opposite the first suckers, surrounded
by excrement compactly pressed, so as to form a sort of cell.
Wherever the larva had reached its full size, the pith of the stalk was found
completely eaten out for at least 5 inches. Below ground even the hard ex- I
ternal portions of the stalk were eaten through, and in one instance everything
except the rootlets had disappeared and the stalk had fallen to the ground. i
In a great majority of instances but a single larva was found in a stalk, but
a few cases were found where two larvae were at work. In no case had an
far filled on a stalk bored by this larva. The stalk was often stunted and
twisted, and the lower leaves were invariably brown and withered.
In one field, which had been completely under water for six days in January, .l
the beetles were apparently as healthy as in fields which had remained above
water. :
INJURIES SINCE 1895.

The records of reports of injury which follow, received by Dr.
Chittenden during the past decade, substantiate the observations of
Dr. Howard made in 1881, and add as well to our knowledge of the
life economy of the species.
In 1895 this billbug was destructive in three localities in Kansas,
complaints all being made during the first week of May. At
Cedar Vale immense damage was done, the insect "taking whole
fields of corn, hill by hill." Similar injury was observed at Dexter
and Leon, these reports having been made by Mr. Hugo Kahl in a :
letter dated July 27, 1898.
The following year Prof. F. S. Earle reported, June 6, injury by
this species at Wetumpka, Ala., on the Coosa River, where there was
great complaint of it as a destructive enemy of corn, especially on
lowv-lving bottom lands. The insect was well known there as a bill-
blug. and was not found on hilly land. It worked below ground, and
when the stalks were not killed outright they put out an immense
number of suckers. The beetles were most destructive to early plant-
ings. corn planted after the middle of May being usually little
injured..
In 1901 Mr. J. E. Williams, Augusta. Butler County, Kans., wrote,
August 28, of injury to corn. Attack commenced as soon as the corn
came through the ground, and the billbugs ate and dug down to the
kernel and devoured that. In larger corn they bored into the stalk
and wintered over in the old stalks, usually below ground. Whole
fields were destroyed, the beetles remaining to continue their work on
second plantings. The insect was known locally as the "elephant
bug." September 6 Mr. Williams sent larvae and adults and their :
i.. .
:I






THE MAIZE BILLBUG.


work in the root-stalks of corn. He had observed that the eggs
were deposited in the stalks, and that these serve for the winter
quarters of the adults; that the beetles began work when the corn
was about 4 or 5 inches high by inserting their beaks in the young
stalks just above ground. By taking hold of the center of the corn
and pulling it it came out. as it was nearly severed as from cutworm
attack. Stalks that had been preyed upon by the billbug did not
yield any amount of seed. No injury was observed to crops other
than corn. Injury was only in lowlands, and the principal damage
was accomplished before the woody outer shell of the stalk was
formed. The beetles were active chiefly after dark, when they trav-
eled, though slowly, from one place to another. They burrowed in
the ground during the day. They were described as "cleaning up
everything as they go, rendering the crop entirely worthless." Sep-
tember 17 another sending of larvwe, pul),T. and images were re-
ceived from the same source. Out of 100 stalks examined by our
correspondent only 10 were free from the ravages of this billbug.
At this date of writing the beetles were deserting the corn.
In 1903 a report was received of injury by what was with little
doubt this species at Griffin. Ga.. although no specimens were re-
ceived, as in all preceding instances cited.

DISTRIBUTION.

This insect has been reported, according to Chittenden,a from
Augusta, Kans. (E. L. Williams) ; Riley County. Kans. (P. J. Par-
rott) ; Florence, Kans.; Dadeville, Ala. (S. M. Robertson) ; We-
tumpka, Ala. (F. S. Earle): Columbia, S. C. (L. 0. Howard) ;
Ballentine, S. C. (J. Duncan) ; Texas (Ulke. 1 ex.); Michigan
(Knaus). It has also been reported from Texas (T. D. Urbahns).
and the writer found it at several points in Oklahoma and Kansas.
Owing to the fact that representatives of the species have been taken
in such widely separated localities, it is very probable that it occurs
over the entire territory between South Carolina and Texas and
northward to Kansas and Missouri.

FOOD PLANTS.

The adults attack young corn plants and probably some of the
coarser grasses. Dr. Howard, and later the writer, found both
adults and larva? feeding on young corn. Mr. Urbahns found
adults at base of swamp grass (Tripsacum dactylokldes) in consider-
able numbers, and probably larvae and pupal of the species in this
same grass (fig. 8). Mr. Urbahns found several Sphenophorus larvae
a Proc. Ent. Soc. Wash., vol 7. No. 1. pp. 59-61. 19075.


15






PAPERS ON CEREAL AND FORAGE INSECTS.


in burrows in thi-s wamip grass and two pupae, but failed to rear
ilthem. Dr. Chittenden determined these pupae as having adult char- ...
acter I of S. tw (idis.
DESCRIPTION AND LIFE HISTORY.

THE EGG.
(Fig. 5.)

Eggs were found by the writer in southern Kansas during June
in punctures made especially for them (fig. 7, b) in young corn
plants. These egg punctures, which the
__ ~ female makes with her beak, are scarcely
visible on the outer surface of the stalk, being
only a slit in the sheath of the plant, through
which the beak. and later the ovipositor, are
___-- ~ thrust, the sheath closing readily when the
FIG. 5.-The maize bilibug egg is deposited and the ovipositor with-
f.Sphuorihorus maidis): drawn. The eggs are about 3 mm. long and
Egg.;-. Enlarged t hree
tieS. EOriginal.)ar 1 mm. thick. creamy white in color, elongate,
and somewhat kidney-shaped, with obtusely
rounded ends. being slightly more rounded at one end than at the
other: the surface is smooth, without punctures.
In the latitude of southern Kansas eggs were laid in the corn plants
during the month of June. where they hatched in from 7 to 12 days,
the young, footless grub thus finding itself sur-'
rounded with the choicest food.

THE LAREVA.
Fig. 6.)

The newly hatched larvae are white, with a light- -:
brown head. the head changing to darker brown
within a few days. The color remains white in the
full-grown larvae, with the head chestnut brown.
The length of full-grown living larvae ranges from e,
FIG. 6.-The maize
15 to 20 mm. and the width from 4 to 5 mm. billbug: Larva.
The following description of the full-grown larva Twice natural
size. (Original.)
was made bv Mr. E. A. Schwarz under the name of
S. robusthis. from the few alcoholic specimens collected by Dr.
Howard at Columbia. S. C.:"
Length 12 mm.; color dingy white; head chestnut brown, with four vittm of
paler color, two upon the occiput, converging toward the base, and one along
each lateral margin: trophi very dark. clypeus paler; body fusiform, strongly
SReport of the Entomologist Deprrtmnient of Agriculture, for 1881 and 188I
p. 141.


16







THE MAIZE BILLBUG.


curved, swelling ventrally from the third abdominal joint posteriorly, slightly
recurred and rounded at anal extremity. Head large, oblong, obtusely augulate
at base, sinuately narrowed anteriorly; frontal margin with a shallow emargina-
tion between the mandibles; upper surface with a median channel, the occipital
portion deeply incised, with raised edges, continuing as a shallow impressed line
to the middle of the front; on either side in engraved line, commencing upon
the vertex, becoming deeper after crossing the branches of the Y suture, and
terminating at the frontal margin in a bristle-bearing depression; sides and
vertex with several long bristles arising in depressions; antenna rudimentary,
occupying minute pits on the front.il margin at the middle of the base of man-
dibles; ocelli a single pair, visible only as translucent spots upon the anterior
face of the thickened frontal margin, outside of and closely contiguous to the
antennae from which they are separated by the branches of the Y suture, a few
pigment cells obscurely visible beneath the surface: clypeus free, transverse,
trapezoidal, with faint impressions along the base and at the sides: labrum
small, elliptical, bearing spines and bristles, a furrow each side of the middle,
forming three ridges, so that the organ, when deflected, appears three-lobed;
mandibles stout, triangular, unarmed, with an obsolete longitudinal furrow on
the outer face; maxilhe stout, cardinal piece transverse, basal piece elongate,
bearing a palpus of two short joints, and a small rounded lobe. furnished at tip
with a brush of spiny hairs, the lobe concealed by the labium; labium consist-
ing of a large triangular mentum, excavate beneath, and a hastate palpiger,
with a deep median channel; labial palpi divergent, separated by the ligula,
of two joints subequal in length; ligula represented by a prominent rounded
lobe, densely ciliate on the under surface. Thoracic joints separated above by
transverse folds: the first wider, covered above by a transverse, thinly chitinous
plate; the two following similar to the abdominal joints; abdominal joints
forming on the dorsum narrow transverse folds, separated by two wider folds,
the anterior fold attaining the ventral surface, the second fold confined to the
dorsum, eighth and ninth abdominal joints longer, excavate ;ibove, without
dorsal folds; beneath, the first three joints contracted, the succeeding joints
enlarged, the terminal joint broadly rounded, with anal opening upon a fold at
its base; sides of each joint presenting numerous longitudinal folds; stigmata
very large, nine pairs; the first on the anterior margin of the prothorax. low
down upon the sides: the remainder upon the sides of the first eight abdominal
joints, above the lateral prominences, beginning upon the first joint at the
middle of the side and gradually rising to a dorsal position upon the eighth
joint: thoracic and last abdominal pairs large, oval; the intermediate pairs
smaller, elliptical; all with chitinous margins of dark-brown color. The notice-
able features of this larva are its cephalic vittTe, and conspicuous spiracles.
Upon issuing from the eggshell the young larvme are about 5 mm.
long and 2 mm. thick. They at once begin feeding on the tissues of
the young corn at the bottom of the egg puncture (fig. 7, b), direct-
ing their burrowing inward and downward into the taproot. When
they finish eating the tender parts of the taproot they direct their
feeding upward, continuing until full grown, allowing the lower
portion of the burrow to catch the frass and excrement (fig. 7, a).
This burrowing of the taproot of the young growing corn plant is
disastrous to the root system (P1. I, figs. 1, 2); the roots, first dying
at the tips, soon become of little use to the plant, allowing it to die
or to become more or less dwarfed (P1. II). The corn plants shown
t


17






PAPERS ON CEREAL AND FORAGE INSECTS.


in Plate I were collected in Kansas and forwarded, in moist paper,
to Washington, D. C., and photographed by the official photographer,
Mr. L. S. Williams, and show the injuries more clearly, while Plate
II, photographed in the field, illustrates the effect on the standing
corn. Small plants, even those of less than one-half inch in diameter,
are often recipients of eggs from which the larvae, on hatching, bur-
row into the heart of the plant and cut off the growing bud, thus
killing the top; they then direct the burrowing downward only to


FIG. 7.-Corn plant showing result of
attack by the maize billbug: o. Larval
burrow containing pupa in natural
position: b. egg puncture containing
eggs. i, Reduced two-thirds; b, en-
larged. (Original. I


FIG. 8.-Swamp grass (Tripsacum
dactyloides). attacked by the
maize billbug. Reduced two-
thirds. (Original.)


devour the stub. leaving themselves without food, and, being footless
grubs, they of course perish. Plants of more than one-half inch
diameter which become infested with larvae make very poor growth,
being very slender, rarely reaching a height of more than 2 or 3 feet
before tasseling (P1. II). and do not produce shoots or ears. Those
that do not become infested until they are half grown may produce
small ears. Each larva inhabits only the one burrow, and if, owing
to any mishap, it becomes dislodged from it, it is powerless to rees-
tablish itself. The larva does not become dislodged from the burrow


18












Bul. 95, Part II, Bureau of Entomology, U. S. Dept. of Agriculture.


FIG. 1.-CORN PLANT INJURED BY THE ADULT OF THE MAIZE BILLBUG (SPHENOPHORUS
MAIDIS), AFTERWARD ATTACKED BY THE LARVA. FIG. 2.-CORN PLANT SHOWING ON
STALK THE EFFECTS OF FEEDING BY ADULT MAIZE BILLBUGS, AND EFFECTS ON ROOTS
OF FEEDING BY THE LARVAE. FIG. 3.-CORN PLANT, MUCH DISTORTED, SHOWING
SUCKERS; FINAL EFFECTS OF FEEDING OF ADULT MAIZE BILLBUGS.
All figures about natural size. (Original.)


PLATE 11.




HEiiii.
: I:.liiii
:::Iii~ iii


* I
:1iiiil'








Bul. 95, Part II, Bureau of Entomology, U. S. Dept. of Agriculture.


CORN PLANTS SHOWING EFFECTS OF FEEDING OF MAIZE BILLBUG IN THE FIELD.
Plant at left not attacked, the two at right attacked by larv.'. 1-educed. i Original.)


PLATE III.



























































kii ::





4
:!. ":






THE MAIZE BILLBUG.


of its own accord. Sometimes there are three or four larvae in the
same plant, their burrows often running into each other, but this
does not appear to discommode them in the least, as they can, and
usually do, all mature. In badly infested fields two larvae are quite
often in the same plant, although one is the usual number and is
sufficient to ruin the plant. The larvae are easily managed in the
laboratory; upon issuing from the eggshell they can be readily han-
dled with a soft camel's-hair brush and placed inside a section of
a cornstalk, where they will feed as readily as upon the growing
plant. As soon as the section of plant is fairly eaten, and before
decay sets in, the larvae must be removed
to fresh sections; keeping them thus sup-
plied with fresh food they can be reared to
maturity.
The length of the larval life ranges from A
40 to 50 days, as indicated by laboratory -,
observations and checked by collections in
the field. They begin maturing and pu-
pating by the 1st of August, pupation I
reaching the maximum by the 20th. and
with the exception of a few stragglers all Cr.-
are mature and changed to pupaw by the d' \.."
1st of September.

THE PUPA. II >, v
(Fig. 9.)
The larve, on finishing their growth, -*'
descend to the lower part of the burrow, 6
to the crown of the taproot, cutting the pith e
of the cornstalk into fine shreds with which Fi,. --The maize billbug
Pupa: a, ventral view; b,
they construct a cell where they inclose dorsal, view: c, anal seg-
themselves for pupation. ment; d thoracic spiracle;
e. abdominal spiracle, a, b,
The newly issued pupae are white, becom- Twice natural size; c, d, e,
ing darker after the fourth or fifth day, and greatly enlarged. (Origi-
continue to darken until just before the na)
adults issue. The adults are reddish black in color. The length of
living pupae ranges from 16 to 20 mm.
The following description of the pupa was made by Mr. E. A.
Schwar'z, of the Bureau of Entomology, under the name of S. ro-
bustus, from the single individual collected by Dr. Howard at
Columbia, S. C.:a
Average length, 17 millimeters. Stout, rostrum reaching between first pair
of. tarsi. Antennue but slightly elbowed and reaching not quite to bend of
Q Loc. cit., p. 142.


19





20 PAPERS ON CEREAL AND FORAGE INSECTS.

;interior femora and tibie. Eyes scarcely discernible. Face with three palmi
of shallow tubercles, the basal pair the largest, and each giving rise to .*
stiff, brown hair. Other minute piliferous tubercles, especially near the pon-. ...
terior dorsal border of the abdominal joints, being very stout on the preanal
joint, or pygidium. where they form two series of quadridentate ridges.
To Mr. Schwarz's description the following may be added:
I.ateral view: Body oblong, thickest at middle; thorax depressed anteriorly; :*
abdomen cylindrical, tapering from seventh segment; thoracic pair of spiracles
very prominent (fig. 9, d), first five pairs of abdominal spiracles prominent (fig.
9. (), the three on the rear segments not prominent. Elytra short, curving :
centrally between middle and hind legs, reaching tarsi of hind leg, covering S
upper half of femur of hind leg; middle leg resting on elytra. ll
The pupl) occur mostly during the latter part of August and first-
part of September and are always to be found in their cells in the
larval burrows near the crown of the taproot and nearly always
below the surface. The pupal period is from 10 to 12 days.

THE A D ULT. i
(Fig. 10.)

The adults are very large, robust, and reddish black when newly
i.'sued, changing to black when older. The original description by
Chittenden a is given here: i
Body two-fifths as wide as long, of robust appearance because of the sub- :
quadrate thorax, which is nearly as wide as the elytra : general color black or :
piceous, moderately shining; altitaceous deposit on unelevated surfaces incon-
spicuous, appearing to be normally dark rufous or piceous velvety when the
extraneous argillaceous covering does not persist. :
Rostrum three-fifths the length of the thorax, considerably arcuate, strongly
subequally compressed, apex prolonged at the posterior angle with an acute
spine, producing the appearance of greater curvature of the inner surface, base
feebly protuberant, moderately dilated; anterior face of apex broadly deeply
concave: surface minutely punctate, more distinctly and densely at base, base "^
moderately deeply channeled with distinct deep interocular puncture and short *
impressed line.
Thorax longer than wide, fully three-fourths as long as the elytra, sides usu- ,
ally widest just in front of middle, anterior third suddenly and very strongly :
nrcuate and constricted at apex, posterior two-thirds or three-fourths subparallel,
or gradually narrowing to the base which is feebly bisinuate. Vittee feebly
elevated, tending toward obsolescence, moderately finely but distinctly and
sparsely punctate, more coarsely and densely at the ends; median vitta eitend-
ihg from a fine line and rapidly widening to a point just in front of the middle
where it is broadly dilated, then more abruptly narrowed, extending in a nar-
rower line to near the base; lateral vittT sinuous with a tendency to become I
confluent with the median in the apical half, generally a little wider in basal s:'
half but narrower than the median, branch wide but ill-defined; interspaces and-..,,
surface at sides coarsely foveate-punctate, punctures becoming confluent, esbe- :..
cially posteriorly at sides. Scutellum deeply broadly concave. .' i
a Proc. Ent. Soc. Wash., vol. 7, No. 1, p. 59, 1905. "i






THE MAIZE BILLBUG.


Elytra little wider than the thorax; strjia usually deep and well defined,
distinctly closely punctuate; intervals with first, third and fifth elevated, with
two or more series of rows of fine punctulation; first or sutural with basal
third triseriately, posterior two-thirds biseriately punctulate; third widest and
most elevated, with four or five rows of fine punctulations; fifth bi's-eriately
punctulate; seventh little or not at all more elevated than the remaining inter-
vals; intervals 2, 4, 6, S, as also 7. more coarsely and closely uniseriately punctu-
late. Pygidium deeply, coarsely mand rather sparsely punctate, with sparse
golden yellow hairs proceeding from the punctures and forming a short tuft
each side, frequently abraded.
Lower surface coarsely and rather densely punctate, scarcely less strongly
at the middle than at the sides, punctures largest at the middle of the meta-
thorax. Punctures of the metepisterna (side pieces) more or less confluent.
Second, third and fourth abdominal segments
nearly uniformly punctured throughout, like
the legs.
$.-First abdominal segment very con-
cave; pygidium truncate at apex.
9.-First ventral scarcely different; pygid-
ium narrowed and rounded at apex.
Aside from the differently shaped pygidium
and the slightly shorter and less compressed
rostrum there is little difference between the
sexes.
Length. 10-15 mm., width, 4.5-6.0 mim.
The adults begin to issue about the
middle of August and continue to do so
until the middle of September. Some
of them leave the pupal cell, but most
of them remain there for hibernation. I
The adults that leave the pupal cell in
the late summer disappear; continued FIGc. I.-The maize hilibug: Adult.
search-in every situation until Decem- Four times natural size. (origi-
1 nal.)
ber failed to reveal a single individual. nal.)
It is evident that they left the cornfield in which they developed,
and it is very probable that they found their way to some dense,
coarse grass (7T. dactyloides), which is abundant in the locality,
The adults hibernating in the pupal cells issue fromni them in late
spring, about the time young corn is sprouting. The beetles are
rarely observed on account of their quiet habits and because they
are covered with mud-a condition which is more or less common
among several species of this genus and is caused by a waxy exuda-
tion of the elytra, to which the soil adheres. The presence of the
adults of this species in a cornfield is made evident by the withering
of the top leaves of very young corn plants, the plants having been
severely gouged. The adults kill the small plants outright and in-
jure the larger ones beyond repair. After the plants grow 10 to 15
inches tall they do not kill them, but gouge out such large cavities
in the stalks that they become twisted into all sorts of shapes (P1. I,


21




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22 PAPERS ON CEREAL AND FORAGE INSECTS.
fig. 3). The attacked plants sucker profusely, affording .......
tender growth for the beetles to feed upon, even for many days .
the noninfested plants have become hard. The corn plants inUjl.
by S. mahiis resemble somewhat corn plants injured by the I.
a.
corn stalk-borer (Diatrcea saccharalis), and are easily disting
from plants inju tired by the smaller species of Sphenophorus o
to the fact that tlhe punctures of the smaller species are not alwayil
fatal to the plants, which, however, in unfolding their leaves, show la.
row or series of rows of round or oblong holes in them.
The females issuing from hibernation feed on young corn for
few days before beginning to deposit their eggs. The egg punctuS
are made by the female in the side of the cornstalk (fig. 7, b) "
neath the outer sheath. These egg punctures are not injuriouansi
the plants, being only small grooves, about 5 mm. long and 8
deep, in which the eggs snugly fit.
NUMBER OF GENERATIONS.
There is only one generation a year. The eggs occur throughofut]
June, larve from early June until September, pupae from the fir.int
part of August until the last part of September, and adults f9tIa
the middle of August until the first part of August of the followi!t|
year. H*.,i
RECORDS OF DEPREDATIONS.
The depredations of this species have probably been confused with
that of other species, the first and only known record of its attaliki
on young corn being that made by Dr. Howard, at Columbia, S. C.*j
During the season of 1910 both adults and larvae were numerous :
cornfields in lowlands in southern Kansas and northern Oklahoxai,
doing serious damage in some instances. They were frequently .
found in uplands, but not in injurious numbers. :
REMEDIAL MEASURES. "
The knowledge of the hibernating habits of the insect suggests an:":;;:
effective remedy in the pulling up and burning of the stubble, which
is also the most practical means of destroying the lesser corn stalk-i
borer (Diatraa sa(charalis). The beetles remain in the taproot of .i
the corn plants until spring, allowing the farmer abundant time to:j
destroy them. Care must be taken, however, in pulling up the:::..
infested stalks or else they will break off above the beetle, leavingii!"
the pest in the ground. The infested stalks, having a very poor 4
root system, are easily pulled. Spraying the young corn plants withz4
arsenical fluids at the time the beetles are making theiriattack is .
very laborious procedure and not very effective..

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UNWER~fY OF FLONiA

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