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 ;
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9 v. : ill. ; 23 cm.
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English
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U.S. Dept. of Agriculture, Bureau of Entomology
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Washington, D.C
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Subjects / Keywords:
Insect pests   ( lcsh )
Vegetables -- Diseases and pests   ( lcsh )
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federal government publication   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )

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Bibliography:
Includes bibliographical references and index.

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University of Florida
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aleph - 029636469
oclc - 758870835
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Full Text
****:: 7 ,


U. S. DEPARTMENT


OF AGRICULTURE,


BUREAU OF ENTOMOLOGY-BULLETIN No. 85, Part II.
L. 0. HOWARD, Entomologist and Chief of Bureau.


PAPERS ON CEREAL AND FORAGE INSECTS.


THE


SLENDER


SEED-CORN


GROUND-BEETLE.



BY
W. J. PHILLIPS,


Agent and Expert.


WASHINGTON:
GOVERNMENT PRINTING OFFICE.
1909.


S... . ....


C/


C w >^,o .


























B UREA U OF ENTOMOLOGY.a .S

L. 0. IHOWARD, Entomologist and Chief of Bureau. .!
C. L. MARLATT, Assistant Entonologist and Acting Chief in Absence of Chief. !i4
R. S. CLIFTON, Executive Assistant.
(C'HAS. J. GILLISS, Chief Clerk. "i

F. H. ('HITTENDEN, in charge of truck crop and stored product insect investigations. I
A. D. IHOPKINS, in charge offorest insect investigations. S
WV. D. II UNTER, in charge of southern field crop insect investigations. i
F. M. WEBSTER, in charge of cereal andforage insect investigations. i
A. L. QL'AINTANCE, in charge of deciduous fruit insect investigations. :
E. F. PHILLIPS, in charge of bee culture. "
D. M. ROGERS, in. charge of preventing spread of moths, field work.
ROLLA P. CURRIE, in charge of editorial work.:
MABEL COLCORD, librarian. I

CEREAL AND FORAGE INSECT INVESTIGATIONS.

F. M. WEBSTER, in charge.

GEO. I. REEVES, WV. J. PHILLIPS, C. N. AINSLIE, E. 0. G. KELLY, J. A. HYSLOP,
W. HARPER DEAN, T. D. URBAHNS, V. L. WILDERMUTH, R. A. VICKERY, T. H. !
PARKS, H11ERBERT OSBORN, agents and expert..

a Organization (f the Bureau on November 1, 1909.
ii




.:.:
:r: .:!
i":


: .i


*:i





















CONTENTS.


Introduction....................................................
D distribution ....................................................
Descriptions and life-history notes .................................
T he egg.................................................... .
T he larva ....................................................
The pupa ................ ....................................
The adult ...................... ................................
Number of generations ........................................
Hlibernation .................................................
Character of ground most liable to infestation................
Rearing experiments .............................................
Character of injury..............................................
Records of depredations ..........................................
Early records ...............................................
Outbreaks near New Paris, Ohio, in 1906, 1907, and 1908.......
Outbreaks in Kansas...........-.-........................
Repellents applied to seed........................................
Experim ents in 1908..........................................
Experiments in 1909 ..........................................
Weather conditions ................................................
Natural enemies ...................................................
Preventive measures .................... ...........................
B ibliography .....................................................


Pare
S 13
13
14
. 14
S 14
. 16
17
S 17
S 18
18
19
S 20
S 21
. 21
22
S 24
. 24
S 24
. 25
. 27
27
. 27
28




























ILLUSTRATIONS.


FIG. 8. The slender seed-corn ground-beetle (Clivina impressifrons): Adult,
eggs, larva, pupa, details.........................................
9. The slender seed-corn ground-beetle: Details of adult................
10. The slender seed-corn ground-beetle: Beetles attacking a kernel of
corn ............................................................
11. Work of the slender seed-corn ground-beetle ........................
12. A cornfield near New Paris, Ohio, about the first week in July,. 1906,
showing results of depredations by the slender seed-corn ground-
beetle ............................ ..................................
13. Same field as in figure 12, about the first week of July, 1908, showing
results of combined work of the slender seed-corn ground-beetle and
cutworms............................ ..............................








U. S. D. A., B. E. Bul. 85, Part II.


PAPERS ON CEREAL AND FORAGE INSECTS.


THE SLENDER SEED-CORN GROUND-BEETLE.
(Clivina impressifrons Lec.)
By W. J. PHILLIPS,
Agent and Expert.
INTRODUCTION.
Observations have been carried on for several years in the vicinity
of New Paris, Ohio, on an interesting little beetle known as the
" slender seed-corn ground-beetle" (Clivina impressifrons Lee.). As
much new information has been secured regarding its early develop-
ment, and since it is probably responsible for some of the injuries
charged up to other insects, it has been thought advisable to make
it the subject of a short paper. As it works below ground, in the
kernels of corn, and confines itself to swampy, peaty soils, the farmer
is likely to believe that the seed fails to germinate and to attribute
the cause to excessive moisture, cool weather, and inferior seed,
never dreaming that this modest little creature is busily collecting his
toll, sometimes as many as fifteen or twenty individuals being found
in or about a single hill.
The writer wishes to acknowledge his indebtedness to Prof. F. M.
Webster, under whose direction this work was carried out. To the
patient and untiring efforts of Mr. V. L. Wildermuth we owe the
information herein presented concerning the habits of the larvme and
pupae. The writer, having previously planned the work, carried on
observations on the adults and their economic relations, and is re-
Ssponsible for the descriptive matter. Acknowledgments are due
Mr. Frederick Knab for helpful suggestions in the preparation of
descriptions.
DISTRIBUTION.
The slender seed-corn ground-beetle belongs to a very large genus,
there being over two hundred species, distributed throughout the
entire world, with the exception of the extreme northern and southern
latitudes. The genus as a whole is supposed to be carnivorous. The
species under discussion is a native of the eastern United States and
is the only one on record as being a plant feeder. Doctor Le Conte
described the species in 1884 and gave New York as its habitat.
Since that time it has been found in Canada, New Jersey, Ohio,
Indiana, Illinois, Iowa, and Kansas.


Issued November 30, 1909.






14


CEREAL AND FORAGE INSECTS.


DESCRIPTIONS AND LIFE-HISTORY NOTES.

THE EGG (fig. 8, a).

A correct description of the egg can not be given, as all those ob0
served are from dissections and have not retained their normal shape|li&|N
They are a little over 1 millimeter in length and over one-halfg::
millimeter thick, obtusely rounded at ends. The chorion is minutely,
reticulate. In color they are a delicate white. It is probable that.'
they are deposited somewhere below the surface of the soil, as the::.
larvae are blind and are found quite deep in the earth. Nothing :
.... f::` :E~
known relative to the period of incubation, as the eggs have never:
been found in the fields. Numbers of adult females were dissected :.
and none contained more than three to four mature eggs, but they i
could be found by this method from early spring on throughout the
entire summer.
THE LARVA (fig. 8, b, e,f).
H'i
Following is a detailed descriptionn of the larva: *|
Color: Head and prothoracic plates dark brown, plates of the other two thmacic:e"I
segments much lighter; cerci and anal tube brown, somewhat dusky at the tips;-..u
abdominal segments pale yellowish; tips of mandibles black; legs dusky. Just after;
molting the larva is a delicate creamy white. A::i
Form: Depressed fusiform; breadth greatest at about the fourth abdominal segment; *I
length a little over six times the greatest breadth; thoracic segments narrower than the
abdominal ones.b
Head quadrate, depressed dorsally, with a deep, broad furrow starting at the base of
the antennae and extending in a posterior direction, gradually fading out; epistomal. i
sutures joining near the base of the head; a deep impression on each side of the head, :::;I
near the base, extending beneath and then anteriorly to base of mandibles; on the .
dorsal surface there is a chitinous ridge at the base of the antennae. :
Ocelli absent. ....
Epistoma reaching posteriorly about three-fourths of the distance from the front of'
the clypeus to the occipital foramen, its lateral sutures sinuate; frontal angles obtuse, '..:ii
rounded.
Clypeus fused with the epistoma. Labrum bilobate, with deeply serrated magin,,. :
Seta: Dorsally there is one large and one small seta immediately at the base of thii;
mandibles; a large seta (in each bide near the margin of the epistomal area, posterior toii
the antennme; several small sette on the clypeal and epistomal areas; a large sets and '4
several smaller ones near the center of the frontal angles; two large setae and several
small set& on the lateral margin of the head; one large sets near the base and slightly:
ventral of the antenna; a small seta ventral of this last one; numerous medium-sized.qi
setae on the ventral aspect.
Antenna? four-jointed; first two joints clavate-cylindrical, joint 2 four-fifths as longI
as joint 1 and at the base about three-fourths as thick; joint 3 broadly clavateant
about one-third longer than joint 2, its outer angle truncate and bearing a promineiti..
acorn-shaped appendix; joint 4 slender, cylindrical, and slightly pointed at the
tremity; joint 3 with two large setae toward the apex, one on the outer and one on i
inner margin, and one on the dorsal face near the base; joint 4 with three large and twd
small sete at the distal extremity.





THE SLENDER SEED-CORN GROUND-BEETLE.


15


Mandibles falcate, slender in front of the retinaculum, apparently smooth; retina-
culum much nearer the base than the tip, small, directed slightly backward; a medium-
sized seta on the outer margin of the mandible near the base.
Maxillae: Maxillary stipes obconical, about 3.6 times longer than wide at its widest
point, slightly curved; two large setae on the outer and oneon the inner margin near the
distal extremity. Outer lobe probably slightly surpassing the first joint of the palpus;
joint 1 clavate, with small seta on inner distal margin, about five-eighths as long and
one-half as broad as joint 1 of the palpus; joint 2 slender, conical, and fully as long as
joint 1. Inner lobe conical, short and inconspicuous, a large seta at its base Pal-
pigerous stipes about three-sevenths as long as joint 1 of the palpus, and larger;
joint 1 slightly clavate, about three times as long as broad; joint 2 apparently cylindri-
cal, not quite half as long as joint 1 and about one-half as broad; joint 3 conical, small,
about two-thirds as long as joint 2.
Labium: Mentum almost quadrate, slightly convex, smooth, much narrower at the
proximal than at the distal end, slightly longer than broad at its broadest point; just
















f!
-A






FIG. 8.--The slender seed-corn ground-beetle (Clirina impressifronm): a, Egg; b, larva; c, pupa; d, adult;
e, ventral view or larval head; f, ventral view of anal segment; g, antenna. All much enlarged.
-(Original.)

below the insertion of the palpi is a large seta; quite hairy except on the ventral sur-
face; ventral surface with a very slight groove down the center; on either side of the
labium are three or four very large setae, probably arising at its base; joint 1 of the
palpus slightly constricted near the base, the distal end the largest, little longer and
about the same width as joint 1 of maxillary palpus; joint 2 conical, and nearly as
long as the two distal joints of the maxillary palpus; the stipes are slight elevations of
the mentum, having no distinct. outline. Ligula minute, nearly quadrate, nearly as
long as joint 1 of the palpus and bearing two small setue.
Thorax: Prothorax nearly as long as mesothorax and metathorax combined; plates
much more strongly chitinized; a slight impression on each side near the anterior
extremity; two large setme on each lateral surface; one large seta on the lateral surface
of the other two thoracic segments; a furrow down the center of each segment (on the
dorsum); one pair of thoracic spiracles situated on the mesothorax just anterior to the
insertion of the legs. Mesothorax and metathorax about equal in size.
Legs: Middle pair slightly the largest, coxa very stout, very thick at the base and
tapering to about one-third the size at the distal extremity; numerous stout spines on






16


CEREAL AND FORAGE INSECTS.


thle anterior face and a few on the-posterior; trochanter not quite three-fourths as lo :i
as coxa on its outer margin; inner margin about one-half as long as outer, distal ..
extremity the largest; femur very slightly clavate, its longest side three-fourths 'aa i
long as the coxa; distal extremity not quite as large as the distal extremity of the cOxa; i
tibia two-thirds as long and two-thirds as large as femur, very slightly clavate; tarsus V
bearing one large claw. A whorl of spines at distal end of tibia; femur and half the :
length of trochanter with a double row of spines on ventral surface; one very long, 1
slender spine on the trochanter, at apex on ventral surface.
Abdominal segments without chitinized plates, increasing in size (in full-grown
larvae) from base outward until reaching segment 4 and then gradually decreasing; a
pair of spiracles on the anterior lateral aspect of each of the first 8 abdominal segments,
so placed as to be visible from above; they are circular and much smaller than the
thoracic spiracles; a large seta on the lateral aspect of each abdominal segment. The
9th segment bears the anal tube and the cerci.
Cerci slightly shorter than the longest abdominal segment, coriaceous, not motile;
seen from above they) are broad and slightly convex; beneath concave, tapering gradu-
ally), toward their distal extremity; the two give the appearance of the letter "U";
the 8 large setae symmetrically arranged with reference to the corresponding setae on
the other cercus; a row of small setae on the inner margin of each cercus, the setse
arranged symmetrically with each other; the other portion of the cerci is densely cov-
ered with setae.
Anal tube apparently as long as the cerci; from lateral aspect appearing cylindrical,
apparently depressed dorsally, curving slightly downward at the tip; ventral margin
of tip irregular in outline and slightly notched; from dorsal and ventral views the tube
has the appearance of a truncated cone; ventrally there are numerous large sete and
a dense covering of small setae; dorsal surface sparsely covered with setae.
The larvae are veritable little cannibals, for besides devouring the
larvae and pupae of other insects they will, in confinement, destroy
each other. They are very difficult to rear, and in no case could they
be carried further than one or two molts. Hence, the length of the
larval stage and the period between instars could not be ascertained.
In confinement they feed readily upon small larvae and the pupae of
other ground-beetles. It is almost impossible to make accurate field
observations on them, as they are found at a depth of from a few
inches to about 2 feet, depending upon the amount of moisture in the
soil. Soon after a rain they will be found within a few inches of the
surface, while during a dry period they go quite deep, apparently
seeking moisture.
THE PUPA (fig. 8, c).

A detailed description of the pupa is given below:
From the lateral aspect: Oblong, increasing in thickness gradually toward the ante-
rior extremity; prothorax depressed; antennae directed dorsally, then ventrally,
around the femora of the first two pairs of legs, the distal half resting between the
elytra and the femora and tibiae of the middle pair of legs. Front femora resting near
the eye. Elytra and wings long and narrow and folded over the posterior pair of legs,
the tarsi of which reach to the posterior margin of the sixth abdominal segment.
Ventral aspect: Head directed downward between the first two pairs of legs, not "
quite one-third length of entire pupa; mandibles closed but not overlapping; from :
the base of the mandibles to the tip about one-third as large as the portion of the head ':i
above them; labrum broad and short, and extending halfway down the mandibles; .J..





THE SLENDER SEED-CORN GROUND-BEETLE.


maxillary palpi conical, long, parallel, and surpassing the mandibles by fully three-
fourths their length; antennae disappearing behind the fore and middle pairs of legs,
coming into view again between the middle tibiae and the elytra. Setae showing but
slightly until just before emergence of adult.
Legs: Fore and middle legs directed forward so that the maxillary palpi touch the
anterior face of the anterior tibiae near the distal extremity; anterior faces of the large,
terminal, tibial spurs nearly touching; tarsi touching for almost the entire length, and
lying between and above the tarsi of the middle legs, extending posteriorly. Middle
tibiae just posterior to front tibiae, parallel to and very close to them. Claws divergent.
Middle tarsi partly beneath the wings, their ventral surfaces facing. Hind tarsi
extending beyond the wings and converging at the posterior margin of the sixth
abdominal segment; ventral surfaces facing; claws divergent.
Elytra and wings completely covering the hind legs, with the exception of the tarsi,
and almost touching beneath. No sete on the ventral surface of the abdomen.
The pupal stage lasts from nine to ten days. When found in the
fields the pupa is always inclosed in a little, oblong, earthen cell,
about one-third of an inch long. Immediately after pupating it is
a delicate creamy-white color. The eyes gradually turn darker, first
becoming red and then black. Other parts of the body change to a
darker yellow and then to a brownish color. The pupa is inclosed
in a delicate, transparent, membranous covering, which splits down
the dorsum when the adult emerges. Pupae are found at a depth of
from a few inches to about 2 feet, depending, apparently, on the
amount of moisture in the soil at the time of pupation.

THE ADULT.

The adult (fig. 8, d, g; fig. 9) is of a dark, shiny-red color and is
somewhat flattened and elongate. The wing covers are narrower
than the thorax. The hinder part of the body articulates with the
prothorax by means of a short peduncle. The fore legs are very
broad and somewhat flattened, the tibiae bearing several large teeth.
The original description by Le Conte will probably not be out of
place here:
Length 31 lines; breadth I line; dark rufous; front with three wide and deep longi-
tudinal impressions, the middle ones abbreviated at the ends so as to form an oblong
fovea; thorax oblong, rounded behind, but little convex, with longitudinal line deeply
impressed; elytra narrower than the thorax, parallel, striate; strive punctate, third
interval with impressed points.
When it first issues from the pupal case the adult, or beetle, is pale
yellow in color, gradually turning to the characteristic shiny red.
NUMBER OF GENERATIONS.

It seems that there are no well-defined broods or number of gen-
erations. The species breeds throughout the entire season, very small
larvae up to full-grown pupe and adults being found at any time
during the summer. The sexes were found in copula, June 14, 1909.
10011-Bull. 85, pt 2-09-- 2


17






CEREAL AND FORAGE INSECTS.


HIBERNATION.
The insects pass the winter in the adult stage. In November, 1908,
careful search was made, during several days, in the cornfields for larva
and pupve, but none could be found, though there were plenty of adults
present. This is not proof but a good indication that they pass the
winter only as adults. Nothing, of course, is known of the eggs as
they occur in the fields.

CHARACTER OF GROUND MOST LIABLE TO INFESTATION.
Larvfe. pupae, and adults seem to confine themselves to low, swampy,
peaty soils that remain moist the entire year. During a very dry


FIG. 9.-Structural characters of Clirina impressifrows: a, Ventral aspect of head and mouth parts; b,
maxilla: c, parts of labium; d, fore leg; e, middle leg; f, hind leg. Much enlarged. (Original.)
period they have only a short distance to go below the surface to find
plenty of moisture. Professor Webster states that he has observed
them in great numbers, floating on the surface of the water in corn-
fields in Illinois, immediately after heavy rains." Mr. W. C. Strom-
berg, Galesburg, Ill., states:b
At another time a friend of mine turned up a nest of Clivina impressjfrons. It was
in early spring. They were clinging to the underside of a log which was very deeply


aCir. 78, Bur. Ent., U. S. Dept. Agr.


18


b Ent. News, vol. 4, p. 150, 1893.





THE SLENDER SEED-CORN GROUND-BEETLE.


embedded in olack soil. In such situations it is rare to find Coleoptera except along
the edges, but here there were Clivinas (closely crowded) on a space not larger than
one's hand.
REARING EXPERIMENTS.
During the summer of 1906, when the writer's attention was first
called to this insect, attempts were made to rear it in confinement.
On June 15 several adults were collected and placed in a glass jar
that had been previously filled with rich soil, and corn planted
therein. No cover was placed on the jar, as the latter curved inward
near the top, rendering this precaution unnecessary.
On August 18 the contents of the jar were carefully examined, but
no eggs or larvae could be found. There were 11 adults-not as many,
however, as were placed in the jar on June 15. They had tunneled
throughout the soil, but the corn had not been attacked. The beetles
were still in good condition in December, though no eggs or larvae
could be found in the jar. Whether artificial conditions tend to
prolong their lives or whether this is the average length of life could
not be ascertained.
October 4,1906, in a field near Richmond, Ind., a tight box 32 by 8
by 10 inches was let down vertically into the soil, a long box filled
with sifted soil being used, so the beetles could go below the frost line
if necessary. Some oats, corn, and wheat were planted in this box
and about 24 adult beetles were placed inside, after which the box
was covered with a closely woven wire screen. They began burrowing
into the soil at once, very much after the manner of moles, parting
and pushing aside the earth with their strong fore legs. On October
8, 42 more beetles were placed in the box. On June 5, 1907, this box
was examined and one adult beetle was found near the top of the cage,
just below the surface of the soil. Several others were found at and
near the bottom, in their burrows, with their abdomens distended as
if containing eggs. These last were apparently dead, though the
tissues seemed to be in good condition, but some of them on being
dissected were found to contain numbers of a little mite, determined by
Mr. Nathan Banks as Canestfinia sp. No eggs, larvae, or pupae could
be found. The fact that comparatively few beetles were present is
probably due to their cannibalistic habits and to the presence of the
mites, it being since learned that the beetles will devour each other
when closely confined or where there is an insufficient food supply.
During the summer attempts were made to rear them in boxes
containing soil from the fields where they had been found injuring
corn, mixed with decaying wood and growing plants of different
kinds, but without success.
In November a box 8 feet long, 3 feet deep, and 2 feet wide, made
of tongue-and-grooved boards, was settled in the ground until the
top was even with the surface. This was done on the farm of Mr.
William G. Baker, near New Paris, Ohio. The box was then filled


19





CEREAL AND FORAGE INSECTS.


with rich, peaty soil from the fields where the beetles had injured::"!
Mr. Baker's corn during the summer. About 40 adult beetles were
placed in this box, which was then covered with closely woven wire ....
gauze.
May 14, 1908, about 50 beetles were collected and placed in the box
prepared the preceding November. During the summer the box
was carefully examined, and while a few adult beetles were found
there were no eggs, larvae, or pupae.
It appeared from these -experiments that the insect could not be
reared in confinement; so, during the months
Sof July and August the cornfields that had
been injured by the Clivina were examined
=& every day, the soil being dug up from a few
,.."' inches in depth to about 2 feet, and exam-.
Sined very closely. July 23 an adult was
i found that had just transformed, being
'\ ly .2 Bl still in the earthen pupal cell. This was
probably among the first to issue this sum-
mer, as none could be found earlier, though
patient, careful search had been made.
tll Numbers of small Carabid larvae were col-
'4 1 elected for rearing, but all either died or
proved to be those of other species. The
Last week in July full-grown larvae were
found in the fields, which soon changed
into pupae. From this time on larvae and
"pupae could be easily found. Several at-
tempts were made to rear larvae through to
;the adults, but without success.
S, Owing to the pressure of other duties, no
i further observations could be made on the
FIGo. 10.-Slender seed-corn ground- species during the summer. However, the
beetles at tacking a kernel of corn;
the body of one protruding from fields were examined carefully during No-
the opening. This is the stage at member, but no larvae or pupae could be
which the major part of the in-
jury is done. Much enlarged. found. From the above it seems that they
(Original.) begin breeding in May or June and con-. :
tinue to do so through August, September, and probably October.
CHARACTER OF INJURY.
As soon as the corn is planted and starts to germinate the beetles
begin to attack it. They usually commence at the germ, often eating
the entire contents, leaving only the hull. Sometimes they begin
their work before the grain starts to germinate, though it is rare to .-
find them attacking kernels in this manner. As previously stated, ;:!
they do not always finish a kernel, but as a rule sufficient injury is ;
effected to prevent further growth. As many as five beetles have .


20





THE SLENDER SEED-CORN GROUND-BEETLE.


been taken from a single kernel, some with part of their bodies pro-
truding from the opening (fig. 1-0). Sometimes the young plant
may push through the earth to the surface of the ground and then
die, owing to the fact that the kernel has been destroyed and the
root system has not developed sufficiently to support it. A plant
with two leaves, that has the kernel entirely destroyed, is shown in
figure 11.
RECORDS OF DEPREDATIONS.
EARLY RECORDS.
The first record of the plant-feeding habit of this species was in
1890,a from Whitley County, Indiana, where germinating seed corn





b ,~






(I









FIG. 1l.--Work of the slender seed-corn ground-beetle. Reduced. (Original.)
was found to be attacked, the beetles starting their work at the germ.
This corn was planted on black, swampy soil.
In 1900 Dr. S. A. Forbesb states: "This little ground-beetle, about
a quarter of an inch long, may receive mere mention as
a beet insect, having once been seen by us in small numbers enlarging
a small excavation on the petiole of a beet leaf. The same species
had previously been seen burrowing freely into seed corn in the
ground."
Five years later Prof. R. H. Pettitt, of the Michigan Agricultural
College, reported the same character of injury to seed corn from the


bBul. 60, Univ. 111. Agr. Exp. Sta., p. 484.


21


a Insect Life, vol. 3, p. 159.






CEREAL AND FORAGE INSECTS.


vicinity of Trenton, Mich.,a having received material with the co i
plaint that "the corn is badly eaten * ." These are thie
only instances on record of the depredations of this beetle previous to::,:.
the outbreak in Ohio in 1906. |j

OUTBREAKS NEAR NEW PARIS, OHIO, IX 1906, 1907, AND 1908. ..:
Some time during the first week of June, 1906, Mr. Win. G. Baker, :i
of New Paris, Ohio, reported that serious injury had been done by a
little brown beetle in his cornfield, which was planted on black,
.. :i


FIG. 12.-A cornfield near New Paris, Ohio, about the first week in July, 1906, showing results of depi--
dations by the slender seed-corn ground-beetle. (From Webster.)

swampy land. Specimens sent to the writer at Richmond, Ind.,
proved to belong to this species. On the 15th of June a personal
examination of the field was made, and the beetles found still work-
ing in the replants, as many as five being taken from one kernel.
Twenty beetles were counted within a few inches of a single hill.
The corn was planted in checks, with thred" to four kernels to a hill, ;
and in many cases ever kernel was destroyed. This field contained:::
about 40 acres, only about 10 to 15 of which were injured, this being ;
the lower part of the field, where the soil was black and peaty. In"i
some places over a third of the corn, replants and all, was missing.
Figure 12 shows the condition of the field a few weeks later. :
a Bul. 233, Mich. St. Agr. Coll. Exp. Sta., p. 50, figcs. 51, 52. .


22




THE SLENDER SEED-CORN GROUND-BEETLE.


On June 7. 1907, Mr. Baker's field was examined, corn having again
been planted in the same field. The first planting of the field was
made during the first week in May, and it was replanted about May 20.
The field was flooded by heavy rains after each planting. Mr. Baker
thought the cool, wet weather was responsible for the poor stand,
but as he had never examined into the cause, it is very probable that
the ground-beetle exacted its usual toll. The field was then planted
for the third time, about the middle of June. Very little of this last
planting was injured. It seems that, as a rule, corn planted about
the middle of June in this locality is not troubled to any great extent.
Experimental plantings made in these fields during the summers of

!:/ ::.. |t .. ..
i ". .....".... ....., *^
















PPV.


FIG. 13.-Same field as in figure 12, about the first week of July, 1908, showing results of combined work
of the slender seed-corn ground-beetle and cutworms. (Original.)

1906 and 1907 were rarely disturbed, though there were plenty of beetles
abroad at the time. No other reason can be assigned for this, except
that early in the season the beetles, being ordinarily carnivorous and
finding animal food scarce, turn their attention to the palatable corn,
whereas later, with animal food plentiful, they do not molest the corn.
May 14, 1908, Mr. Baker's fields were examined and the beetles
found to be quite abundant, often as many as 30 to the square yard
Being found. Corn had not been planted up to this date, but the
ground-beetle did considerable injury to this field later. Cutworms,
probably Agrotis ypsilon Rott., and the beetles together destroyed at
least 50 per cent of the corn on the lower part of the field, fully one-
half of this being the work of the beetles. Figure 13 shows the con-
dition of the field about the first week in July.


23





CEREAL AND FORAGE INSECTS.


OUTBREAKS IN KANSAS. 1
Prof. F. M. Webstera states that in 1906 Prof. E. A. Popenoe, o
Manhattan, Kans., called his attention to two instances where vYe
serious injury had been done in cornfields in the southeastern partcI
the State, specimens having been sent with each report. Professor i
Webster stated also that there were numerous complaints in Kansas l:
during that year pf corn not germinating and of failures to get-as&ii
stand on low, swampy land. The greater part of this injury was::
probably caused by the ground-beetle.
A great many reports of injury are never investigated, it usually .....J
being taken for granted that the depredations are caused by wire
worms or some other well-known pest, while a large part of the injury 5
is probably due to the ground-beetle. .i

REPELLENTS APPLIED TO SEED.
As it is a well-known fact that some odors are offensive to insects, "
a series of experiments was conducted in order to learn if the seed 3
could be treated with some odorous preparation that would repel ';
the attacks of this pest, and, at the same time, be cheap and'easily
applied. It was decided to use a liquid, as any form of powder or
paste would increase the size of the kernel appreciably so that it would
not readily pass through a planter. Several heavy oils having odors :;
more or less repellent to insects were selected, as it was believed that
these latter would remain longer in the soil after the treated seed I
was planted. Oils of lemon, cajeput, citronella, wormseed, and -
mustard, and carbolic acid were used. The oils were diluted to
10 per cent solutions in wood alcohol and applied at the rate of i
3 ounces to a gallon of corn. Carbolic acid was diluted in water to a.
3 per cent solution and applied at the same rate. The liquids were
poured over the corn, which was then stirred vigorously so that '
each kernel would be completely coated. In planting the checks, all
the corn was removed from the planter and the latter filled again |
with fresh, untreated seed. i
EXPERIMENTS IN 1908.
Mr. Win. G. Baker, near New Paris, Ohio, whose fields had been so
badly affected, consented to have the experiments on his farm. Each
plat consisted of four rows across his field in the worst infested area. :j
The beetles were very abundant, as many as 30 to the square yard ,i[
often being found. The numbers of the several plats and the oils ji
with which the seed in each was treated are as follows:
Plat 1, oil of lemon; plat 2, oil of cajeput; plat 2a, check (not :
treated); plat 3, oil of citronella; plat 4, oil of wormseed; plat 4a, S:
a Cir. 78, Bur. Ent., U. S. Dept. Agr., 1906, p. 5. |


24





THE SLENDER SEED-CORN GROUND-BEETLE.


4 check (not treated); plat 5, oil of mustard; plat 6, carbolic acid. The
plats were planted May 21, 1908.
All plats were examined on June 1, 2, and 3, 1908. Every hill that
contained no live plants, or that had only one plant, was dug up and
examined carefully. Two hundred hills in both the experimental
h and check plats were inspected. The results are summed up briefly
in the following table:

TABLE I.-Results of experiments in treating seed-corn with repellent oils to ward off
attacks of the slender seed-corn ground-beetle.

SDestroyed by Destroyed by
I Clivina. i other pests.
umer: Per cent Per cent
Number
Plat hills ex- b Number Total. Number Number I Total. affected affected
No. mined. Number hills Number hills by by other
amed. hills en- with hil Clivina. pests.
tirelyde- onl tirelv de- wt
stroyed only 1 stroked, only
sry plant. -e plant.

S 1 200 11 19 2-5' 27 52 9.5 26
2 200 8 11 19 15 42 57 9.5 28.5
2a 200 11 21 32 28 30) 58 16 29
3 200 7 11 IS 21 35 56 9 28
4 200 12 16 26 3t 49 85 14 42
4a 200 10 20 30 21 3S 59 15 29.5
5 a 200 .......... .......... .......... .......... .......... ...... .. .......... ........
1 6 200 10 12 22 21 20 49 11 24.5
.0II I
a In plat 5, a very large percentage of the seed did not 2ermiinate and it is to be inferred that the kernels
were injured by the oil, therefore this plat was not included in the table.

No attempt was made to ascertain the number of hills destroyed by
each individual pest other than the Clivina. A cutworm, probably
Agrotis ypsilon, caused a large amount of injury. Wireworms and
the seed-corn maggot were also responsible for a part of the trouble.
The oil of wormseed probably injured the kernels, as a much larger
number of plants in plat 4 were missing than in some of the others.

EXPERIMENTS IN 1909.

After looking over the results of experiments conducted during the
year 1908 it was decided to use the oils of cajeput, citronella, and
lemon, as these promised the best results. Two small plats (Nos. 5
and 6) were planted later than the others, one (No. 6) with and the
other (No. 5) without fertilizer, the fertilizer being placed directly
on the corn.
The plats were in the same place as those of the year 1908, and con-
ditions were the same as regards the size of the plats and the quanti-
ties of materials used. The treatments given the several plats were
as follows: Plat 1, oil of cajeput; plat 2, oil of citronella; plat 3, oil
of lemon; plat 4, check (not treated); plat 5, 95 hills planted June 2
S (unfertilized); plat 6, 93 hills planted June 2 (fertilized). Plats 1
I to 4 were planted May 22, 1909.


25








26 CEREAL AND FORAGE INSECTS. I

Plats 1, 2, 3, and 4 were examined June 5 and 7, and plats 5 and BIt..
examined June 14. The same plan that was used last year was;i&.
adopted. The following table gives a brief summary of the results:

TABLE 11.-Results of experiments in the treatment of seed corn to ward off attacks of tUse;.
slender seed-corn ground-beetle. ,;


Destroyed by
Clivina.

Number Number Total.
hills en- hills
tirely de- with only
stroyed. I plant.

S 10 18
20 1 14 34
17 3 18 35
5 16 21
5 7 12
5 11 16


Destroyed by other
pests.

Number Number
hills en- hills
tirely de- with only
stroyed. 1 plant.

.......... 46
.......... 24
.......... 24
.. .. .. .. .. 13
3 9
8 10


The last two plats (5 and 6) should not have been planted until
about June 10. Normal results could not be expected from such
small plantings, as the beetles were no longer working on the larger
corn; consequently the percentage of beetles to the hill in these plates
must necessarily have been much larger than in the early plantings,
when the whole field was planted at once.
In plats 2 and 3 it will be noted that 20 and 17, respectively, are
the number of hills mentioned as being entirely destroyed by the
Clivina. In both of these plats were found hills that contained no
seed, and, as no other cause for this could be assigned, the whole was.
charged up to the Clivina.
Three checks near the plats were examined, counts being made of
the number of hills with only one plant. None of these hills was dug:
up, as Mr. Baker had replanted the corn, and, of course, this would
have interfered with the results.
The following table gives the results of counts in these check areas:

TABLE III.-IRtsilts qof C.raTmination of check areas of corn as to injury from the slender'
seed-corn ground-beetle.


Check number.



I..................................................
2 ... ..... .. .. ....................... . .. .. .. .. .. .. .. .. .. ..
3 .. .... ... ... ........................... .... .... ...... .........


Number
hills ex-
amined.


200
200
200


Number
hills with
plants
entirely
missing.

24
20
17


Number Total per I
hills with cent of
only 1 hills
plant, affected. ..
....:. :..

44 34
36 28
46 318



'" II


Plat '
No.




1
2
3
4
5
6


Nmnler
hills ex-
aminied.



200
200
200
200
9.5
93


Total.




46
24
24
13
12
18


Per cent
affected
by
Clivina.



9
17
17.5
10.5
12.6
17.4


Per cent
affected
bother
pests.



23
12
12
6.5
12.6
19.3





THE SLENDER SEED-CORN GROUND-BEETLE.


WEATHER CONDITIONS.
The facts concerning the temperature and moisture of the periods
over which the experiments, described above, extended were obtained
from Mr. Walter Vossler, the local observer at Richmond, Ind. The
conditions prevailing at Richmond were very nearly the same as
those at Mr. Baker's farm, which is only 8 miles away.
The following table gives the maximum, minimum, and mean tem-
peratures and the rainfall in inches for the months of April, May, and
June in 1908 and 1909:
TABLE IV.-Temperature and rainfall conditions at Richmond, Ind., April, May, and
June, 1908 and 1909.
Montn.- Maxi- Mini- Rain-
Month. axi- Mini- Mean. Month. M Mean. -
mum. mum. fall. mum. mum. fall.

1908. Inches. 1909. Inches.
A ril........... 80 24 52 3.76 April............ 82 20 51 4.68
...y ......... 92 29 60 4.97 May............. 83 32 57 5.37
June.............. 93 39 66 2.69 June ............ 88 47 67 5.74

NATURAL ENEMIES.
A small mite (Canestrinia sp.) has been found in great numbers in
the abdomen of the adult beetles. As cited on page 19, this mite
apparently destroys the beetles, though nothing definite has yet been
learned as to the extent of the destruction from this source.
PREVENTIVE MEASURES.
Since the beetles confine themselves to low, swampy land, it would
appear at first glance that the remedy is very simple-cease planting
such land to corn. However, to a man whose farm consists chiefly
of such land, this would seem very poor advice. In the vicinity of
Richmond, Ind., corn planted about the middle of June is but little
disturbed. From the foregoing it would appear that the greater part
of the damage may be avoided by late plantings. This would seem
to offer some relief. The class of soil mentioned above usually re-
mains wet and cold until quite late in the spring, but even in case the
spring should be a dry one, the extra time could be very well em-
ployed in preparing a good seed-bed.


27








28 CEREAL AND FORAGE INSECTS.

...... ....
BIBLIOGRAPHY. "

BEUTENMULLER, WM., and LENG, CHAS. W.-Journ. N. Y. Ent. Soc., vol. 1, p. 96,
1893; Ibid., p. 187, 1894. ...
FORBES, S. A.-Eighteenth Rep. State Ent., on the noxious and beneficial insects .
of the State of Ill., p. 15, PI. II, fig. 5. Trans. Dept. Agr. of the State of Ill., 1894. :
Separate: Springfield, Ill., 1894, p. 171, 15 pls. |
FORBES, S. A.-Bul. 44, 111. Agr. Exp. Sta., on the insects injurious to the seed and "
root of Indian corn, May, 1896, p. 217, fig. 5 [Abstract of 7th Rep. of the State Ent.
of Ill.]. '
FORBES, S. A. and HART, C. A.-Bul. 60, 111. Agr. Exp. Sta., on the economic ento- '
mology of the sugar beet, p. 484, fig. 60, October, 1900.
HART, C. A. and FORBES, S. A.-Bul. 60, 111. Agr. Exp. Sta., on the economic ento -
mniology of the sugar beet, p. 484, fig. 60, October, 1900.
LENG, CHAS. W., and BEUTENMULLER, WM.-Journ. N. Y. Ent. Soc., vol. 1, p. 96,
1893; ibid., vol. 2, p. 187, 1894.
PETTIT, R. H.-Bul. 233, Mich. State Agr. Coll. Exp. Sta., p. 50, figs. 51, 52.
STROMBERG, C. W.-Ent. News, vol. 4, p. 150, 1893.
WEBSTER, F. M.-Insect Life, vol. 3, p. 159, 1890. ..
WEBSTER, F. M.-Cir. 78, Bur. Ent., U. S. Dept. Agr., 1906.
WICKHAM, H. F.-Bul. Lab. Nat. Hist., Univ. of Iowa, vol. 3, No. 3, p. 37, March, ,...
1895. Supplement to the List of Coleoptera of Iowa City and Vicinity. "
W'ICKHAM, H. F.-Proc. Iowa Acad. Sci., vol. 2, p. 45, 1894. Report of the corn- ,
mittee on the State fauna, Des Moines. :
WOLCOTT, A. B.-Ent. News, vol. 7, p. 234, 1896.




















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