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:
AA00018926:00002

Full Text




U. S. DEPARTMENT


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


PAPERS ON CEREAL AND FORAGE INSECTS.


THE TIMOTHY

A NEW TIMOTI


STEM-BORER,

IY INSECT.


BY

W. J. PHILLIPS,


Entomological Assistant.



ISSUED MARCH 31, 1911.


WASHINGTON:
GOVERNMENT PRINTING OFFICE.


1911.


OF AGRICULTURE,


.. . .. .



























B UREA U OF ENTOMOLOGY

L. 0. HOWARD, Entomologist and Chief of Bureau.
C. L. MARLATT, Entomologist and Acting Chief in Absence of Chief.
R. S. CLIFTON, Executive Assistant.
W. F. TASTET, Chief Clerk.


F. H. CHITTENDEN, in charge of truck crop and stored product insect
A. D. HOPKINS, in charge of forest insect investigations.
W. D. HUNTER. in charge of southern field crop insect investigations.
F. M. WEBSTER, in charge of cereal and forage insect investigations.
A. L. QUAINTANCE, 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 u'ork.
MABEL (C'OLCORD, librarian.


in restigations.


I.


CEREAL AND FORAGE INSECT INVESTIGATIONS.

F. M. WEBSTER, in charge.

GEO. I. REEVES, C. '. AINSLIE, J. A. HYSLOP, WV. R. WVALTON, T. D. URBAHNS, V. L.
WILDERMUTH, R. A. VICKERY, T. H. PARKS, HERBERT T. OSBORN, agents and
experts.
W. J. PHILLIPS, E. 0. (-. KELLY, GEO. G. AINSLIE, PHILIP LUGINBILL, entomological .
assistants.
NETTIE S. KLOPFER, preparator,
II


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C0 NTE NTS.

PEge.
Introduction .............................................................. 1
H history .................................................................... 1
D distribution .............................................................. 2
Character of attack ........................................................ 2
H ost plants ............................................................... 2
Description of the different stages .......................................... 3
The egg ............................................................... 3
The larva ............................................................... 3
The pupa .............................................................. 5
The adult .............................................................. 6
Life history and habits ..................................................... 6
The egg ............................................................... 6
The larva .............................................................. 6
The movements of the larva in the stem ........................ ..... 6
The movements of the larva outside the stem ......................... 7
The pupa ................... ........................................... 7
The movements of the pupa in the stem............................. 7
The movements of the pupa outside the stem.......................... 8
The adult .............................................................. 8
Life cycle ................................................................. 8
Length of the several stages............................................. 8
Hibernation............................................................... 8
Parasitic enemies .......................................................... 9
Remedial measures......................................................... 9





ILLUSTRATIONS.


PLATE.
Page.
PLATE I. The timothy stem-borer (Mordellistena ustulala): LurvaM and pupa
in stems ........................................................ 8
TEXT FIGURES.

FIG. 1. The timothy stem-borer (Mordellistena ustulala): Adult................ 2
2. The timothy stem-borer: Egg....................................... 3
3. The timothy stem-borer: Larva and details............................ 3
4. The timothy stem-borer: Pupa and details.......................... 5
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U. S. D. A., B3. E. Bui. 95, Part I.


PAPERS ON CEREAL AND FORAGE INSECTS.


THE TIMOTHY STEM-BORER, A NEW TIMOTHY INSECT.
(Mordellistena ustulata Lee.)
By W. J. PHILLIPS,
Entomological Assistant.
INTRODUCTION.
The writer's attention was first attracted, in 1904, to the interesting
little insect which is the subject of this paper. On November 29 of
that year, at Rives, Tenn., while examining timothy for joint-worms
(Isosoma), a curious little larva, unknown at that time to the writer,
was found tunneling the stems. In many cases it had traversed
the entire length of the stem, from the top joint to the bulb. Although
nothing was reared from this material it served to arouse interest.
Since that time, however, it has been reared and some interesting
facts learned concerning its habits and manner of living.
Thus far it has not proved a serious pest, having been found only
in small numbers at any given point. In large numbers it would
scarcely 1do any perceptible injury to the hay crop, although it could
probably very materially lessen seed production. For this, as well
as other reasons, it deserves more than passing notice.
HISTORY.
The adult (fig. 1) was described by Le Conte in 1362, but there is
no reference in literature to its larval habits, although as early as
1877 it was known that larve of other species of this genus inhabited
plant stems of different kinds.
During the early part. of November, 1904, Mr. Geo. I. Reeves, of
this Bureau, found larva tunneling timothy stems at Richmond
and Evansville, Ind., and at Nicholsville, Ohio, but none was reared.
In the latter part of the month the writer found a larva working in
timothy stems at Rives, Tenn. Nothing could be reared, but in the
light of recent observations ,it is very probable that they were Mor-
dellistena ustulata in each instance.


C. F T. T., March 31, 1911.






2 PAPERS ON CEREAL AND FORAGE INSECTS.

In 1905 the writer found numbers of larvae inhabiting timothy at
Richmond, Ind. Some time in the fall infested stems were collected
and sent to the Department for rearing, but it was the same story-
nothing issued.
Early in the spring of 1906 observations were begun with a view
to rearing the adult. Infested stems were collected in May, and on
June 8 the first adult appeared. Specimens were later submitted to
the Department and were found to belong to the above species.
Since that time they have been reared repeatedly.
^ DISTRIBUTION.
The habitat of this insect has
been given as the middle and
southern United States. Adults
y have been captured as far east
as Pennsylvania, and they have
been reared from material col-
lected in Indiana, Ohio, and Vir-
/ ginia. Timothy stems contain-
ing mordellid larvea that were
inot identified, but which were
--- probably Mordellistena ustulata,
were found in Kentucky, Ten-
nessee, Illinois, and, this year,
AMr. T. H. Parks, of the Bureau
Sof Entomology, found them at
h Chillicothe, Mo.
CHARACTER OF ATTACK.
FIG. 1.-The timothy stem-borer (Mordellistena ustu-
lata): a, Adult or beetle, dorsal view; b, same, lateral
viewv. Greatly enlarged. (Original). AS a rule the egg is deposited
at or slightly below the center of
the first or second joint in timothy, but much farther down the stem in
other grasses. From here the larva bores into the center of the stem
and then begins its downward journey to the bulb or root. It feeds'
upon the pith and the walls of the stem as it passes downward, and
when it encounters a joint it tunnels completely through it, leaving a
mass of detritus behind. Plate I is an illustration of its workmanship.

HOST PLANTS.
This species has been reared from timothy, orchard grass (Dac-
tylis glomerata), quack grass (Agropyron sp.), and Agrostis alba, while
larvae that were supposedly this species have been found in bluegrass
(Poa spp.) and cheat (Bromus secalinus).






THE TIMOTHY STEM-BORER.


DESCRIPTION OF THE DIFFERENT STAGES.

THE EGG.
(Fig. 2.)
Length 0.65 mm., diameter near center 0.16 mm. Color milky white. Acuminate-
ovate, apparently smooth; one side convex and the other slightly concave; large end
broadly rounded, small end acutely rounded.
Described from specimens dissected from
gravid females. ,.
THE LARVA. ,.....
(Fig. 3, a.) FIG. 2.-The timothy stem-
borer: Egg. Highly magni-
Length 6 mm., diameter 0.875 mm. Color varying fled. (Original.)
from creamy to white, shading into a very faint tinge of
salmon near center. None of the segments appears to be corneous, although each
bears a numl)er of setaT; last segment feebly bifid, ending in a two-pointed spear,
and covered with stout bristles. Dorsal surface of abdomen with six pairs of fleshy
tubercles which will be described
later.
Head (fig. 3, b) narrower than
S( thorax and arranged almost ver-
\\\ \ \ tically with reference to it; ovoid,
Nf \ smooth, and bearing a number
S/ \of large and small setae, a very
S- .faint suture extending from the
F \\ \occipital area almost to the episto-
S mral area.
Antennx represented by two
:- 'fleshy tubercles, situated laterad
b' of and near insertion of mandi-
t bles; somewhat cone-shaped and
2; r C bearing several small seta- on their
'^ 's / J summits.
/. Eyes represented by two tiny,
slightly fused black dots situated
/i, 1/ \slightly ventro-laterad of the an-
^ i ^ '^Vv~k^^ ^ tennse.
t Q 'tr 4 AEpistoma sublunate; anterior
W'' *" Ji } margin concave and posterior con-
a c vex; about twice as broad as long
and apparently inclosed by base of
FIG. 3.-The timothy stem-borer: a, Larva, lateral view; mandibles and a chitinous ridge ex-
b, head of same, dorsal view; c, maxillae and labium of tending from insertion of mandibles
same; d, mandible of same. a, Greatly enlarged; b, d, tending from insertion of mandibles
more enlarged; c, still more enlarged. (Original.) almost entirely across the face; ridge
amber-colored.
Labrum tonguelike, lying directly over the mandibles, rectangular, longer than
broad; distal margin rounded and densely fringed with setae or bristles; upper
surface pappose; two large setae near center an& two on eachr lateral margin; six
smaller ones on distal margin.
D5


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PAPERS ON CEREAL AND FORAGE INSECTS.


Mandible (fig. 3, d) short, very broad at base, almost as broad as long, tapering
abruptly to a sharp point; outer face convex and smooth, with a small seta near .
center; ferruginous at base and black at extremity, strongly curved; inner face ]1
concave, with two small notches midway of superior margin and one small notch near
extremity of inferior margin.
Maxilla (fig. 3, c) inserted far to the rear, large, fleshy, curving considerably, thus
inclosing the labium; extending considerably beyond tips of mandibles; distal .,
extremity bearing the two-jointed palpus and the lacinia. Each maxilla bears a :
number of sete, one large and two small ones occurring on outer face, a large one at
outer and one at inner angle of base of palpus, and two small ones and one large one
caudad of these. The lacinia is a brushlike organ bearing a fringe of stout bristles. I
Maxillary palpi (fig. 3, c) two-jointed; first joint slightly obconical, about as thick
as long, bearing several sette on the outer face; the second joint is a slightly truncated
cone, and much smaller than the first joint, and bears a number of minute setse at :
the apex. HI
The labium (fig. 3, c) is a very simple organ inserted between bases of maxillhe,
fleshy, rectangular; distal extremity sharply rounded and fringed with minute sete,
with two larger setae at tip; four sete forming a semicircle near center, the two in :
the center much the largest; a large seta at inner angle of base of each palpus. Labial ::
palpi (fig. 3, c) very minute, two-jointed; first joint cylindrical; second joint almost
cylindrical but much smaller than the first and slightly rounded at tip, bearing :
several minute setae.
Prothorax as large as the two following segments combined; viewed from side
triangular in form; not wrinkled or folded but finely striate; dorsally the posterior
margin extends back for a considerable distance into the mesothorax. The meso-
thorax and metathorax lie at quite an angle with the abdominal segments; posterior
margin of dorsum of mesothorax extending back to center of metathorax. Meta-
thorax about same width as mesothorax, except on dorsum, where it is somewhat :
narrower.
Legs fleshy, cone-shaped, four-jointed; first joint very large and more like a pro-
jection of the thorax than a joint of the leg; second joint obconical, very short, and
very much smaller than the first; third joint, cylindrical, short, and very small;
fourth joint the smallest of all, obconical, rounded at apex, and bearing three spines
at tip; a whorl of spines at each joint on outer face; segments very imperfectly defined
in most cases. :
Abdomen composed of nine segments, all of which are broader than the mesothorax
or metathorax. First six segments bearing on their dorsal surface two round, fleshy, .I
somewhat retractile elevations or tubercles (M. Perris, in his Larves des Col6optkres,
calls them ampoulee ambulatoire.") These tubercles are almost circular in form
and the apex is crumpled and folded and bears several small setae. Dorsum of the
seventh segment with a slight transverse ridge bearing a number of recurved bristles; .
eighth segment bearing a number of bristles, which are more numerous near posterior ,
margin, all directed backward. First eight segments with a large fold extending
their full length on each lateral face, most prominent near center of segments, at which
points there are a number of bristles directed slightly to the rear. Ninth segment
somewhat cone-shaped, densely covered with stout bristles, ending posteriorly in a ,
two-pointed, chitinous projection; just below this, dorsally, are two chitinous spurs !
or tubercles. ;
Stigmata: Nine pairs of stigmata, one pair in mesothoracic region just above and :
slightly in front of insertion of legs and a pair to each of the first eight abdominal t j
segments, very near the anterior margin and just above the lateral fold. They are
circular in form, the thoracic being slightly the larger.
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THE TIMOTHY STEM-BORER.


THE PUPA.

(Fig. 4.)
From the lateral aspect: Length 5 mm., diameter in thoracic region 1.125 mm.
Pale cream color, somewhat acuminate-ovate, broadly rounded at head and thorax.
Prothorax, from the lateral view, triangular, the dorsal surface being the base of the
triangle, which is very broad and convex. Antenna passing upward at side of eye,
between margin of prothorax and front femora, thence to dorsum, curving backward
over base of wings. Wing-pads long and narrow, covering posterior legs, with the
exception of the last three tarsal joints; front wings nearly covering hind ones.
From the ventral aspect (fig. 4): The front of head is in almost direct line with the
body; mandibles small and not closed; palpi widely separated and extending beyond
front tibiae. Femora of first pair of legs directed dorsally, tibiae resting on middle femora;
first tarsal joints resting under tip of palpus; tarsal joints then extending caudad,
almost parallel, except last two joints, which slightly diverge. Femora of second pair
of legs parallel to femora of first pair, second
tibiae, however, forming a greater angle with their 'S ,-
femora than tibiae of first, pair of legs; second -
femora and tibiae resting upon wings for a part of -
their length; tarsal joints gradually converging un- /
til the last two, which nearly touch between
wing pads. Third pair of legs covered by wing
pads, with exception of last two joints and a part
of third; last two parallel, touching, and extending ,'
to middle of sixth abdominal segment.,/A
Dorsal surface of the'first six abdominal seg-'. ," '
ments almost flat, and in the third, fourth, fifth, "
and sixth segments the surface produced laterally '
into a fleshy fold projecting over side of abdomen, ,
the anterior margin of which is rounded and the A -
posterior square, giving the abdomen a notched \
appearance; in center of each projection laterally ..e "
is a group of recurved bristles. c 6
Seventh abdominal segment (fig. 4), from a FIG. 4.-The timothy stem-borer: a,
lateral view, cylindrical anteriorly; posteriorly Pupa, lateral view; b, ventral view
the dorsal surface is drawn out. into a long cone- of same; c, ninth segment of same;
d,setigerous tubercle of sixth segment.
shaped projection, the tip of which extends a, b, c, Greatly enlarged; d, more en-
a, b, c, Greatly enlarged; d, mnore cn-
beyond the last abdominal segment, resting large. (Original.)
between its two chitinous spurs; ventral surface
extending backward into a fleshy fold or lip, beyond insertion of following segment.
Eighth segment. (fig. 4) somewhat cylindrical anteriorly, telescoping into seventh;
dorsal surface extending backward into a large fleshy projection or lip, almost filling
space between cone-shaped projection of preceding segment and Y-like chitinous
projection of following segment; a deep lateral notch or incision, but ventral projection
much shorter than dorsal.
Ninth segment (fig. 4) smallest, telescoping into eighth, and extending posteriorly
into a Y-like projection, the tips of which, inclining forward, are amber-colored,
chitinous, and spinelike.
Setae: Numerous setae on ventral surface of abdomen, on head, and on prothorax.
First abdominal segments bearing a few setav on dorsal surface; there is a small trans-
verse ridge on dorsum of second segment, bearing a row of setae; following four segments






PAPERS ON CEREAL AND FORAGE INSECTS.


bearing each two recurred, fan-shaped, fleshy elevations or tubercles, increasing in '.
size with each successive segment (fig. 4, d); each elevation simple and bearing a
fringe of bristles directed to the rear. i!
Last three segments bearing a number of bristles; cone-shaped projection of seventh
rather thickly studded and last segment densely covered with stout bristles, all l
directed to the rear.' :'l
THE ADULT. I
(Fig. 1.)I
The description by Le Conte is as follows: I
Hind tibia with two oblique ridges on the outer face; ridges parallel, the anterior
one extending almost across the outer face of the tibia; first joint of the hind tarsi with
three, second with two oblique ridges; elytra ferruginous, with the suture and margin
blackish: ferruginous, black limb of the elytra very narrow; abdomen, and sometimes ::
the hind coxa* and pectus, blackish. 9-11. '1
LIFE HISTORY AND HABITS.
THE EGG. :
.**"
Females have never been observed in the act of oviposition and
the period of incubation of the eggs has never been determined. The
latter would be rather difficult to obtain, as eggs that are deposited
in living plant tissue rarely hatch after they have been exposed to
the air.
As stated above, the egg is usually deposited at and slightly below
the center of the first or second joint from the top, within the plant
tissues.
The number of eggs that one individual is capable of depositing has
not been ascertained. Upon dissection females have never been
found to contain more than four fully developed eggs and several
immature ones, but they probably deposit a much greater number
than this.
THE LARVA.
Upon hatching, the young larva apparently destroys the tissue *
immediately surrounding it, thus forming a minute cell or cavity, .
It then eats its way into the center of the stem and starts downward,
tunneling the joints as it reaches them, and at harvest time the
earlier ones are below the fourth joint, where they will be out of
danger of the mower. By fall they have reached a point just above
the bulb. i
THE MOVEMENTS OF THE LARVA IN THE STEM.
The manner in which the larva propels itself up and down the stem
is very interesting. It can ascend or descend the stem, forward or ,|
backward, apparently with equal facility. The maxillae, which extend .
beyond the mandibles, the true legs, the dorsal tubercles or feet, and 4i|
the anal segment all play a part in its movements. In going forward !
the abdomen is advanced by means of. the dorsal tubercles, which act i






THE TIMOTHY STEM-BORER.


as feet; the body is then braced by fixing the spines of the anal seg-
ment against the opposite wall of the stem; the maxille and true feet
then advance the thorax and head. By executing these movements
almost simultaneously the larvae can move quite rapidly. In going
S backward the movements are reversed. The dorsal feet or tubercles
and the anal spines enable thle larva to support itself in the stem.
THE MOVEMENTS OF THE LARVA OUTSIDE THE STEM.
Naturally enough, as the larva seems peculiarly adapted for move-
ment in a small hollow stem, when it is placed on a flat surface it
appears wholly at a loss how to proceed. It arches its body and
turns on its side, going through the same movements as though it
were in a stem, but it moves very slowly. It then turns on its back
and tries to walk on its dorsal feet. By bringing all of its knowledge
of the different ways of walking to bear on the problem, it moves
slowly, in a drunken way, to a protecting object, if any be near.
THE PUPA.
When ready to pupate, the larva (Plate I, a) reverses its position
in the stem and ascends to a point anywhere between the first joint
from the root and the first or second joint from the top, depending
upon whether the timothy has been cut or not. Plate I, b, shows
a larva ready to pupate, just below the second joint from the root.
It probably locates most often just above the first or second joint
from the root. It then seals up the stem above and below with
detritus, making a cell of from 1 to 2 inches in length. It will reseal
a stem if interfered with, but if its burrow be molested many times
it will live for weeks and not pupate, finally dying.
After inclosing itself within this cell the larva becomes sluggish,
contracts slightly, and thickens perceptibly in the thoracic region.
It soon casts its larval skin and becomes a fully developed pupa.
In Plate I, c, is seen a pupa in its cell just above the second joint
from the root. After pupation it is a pale cream color, gradually
changing to a brownish tint.
THE. MOVEMENTS OF THE PUPA IN THE STEM.
The movements of the pupa in ascending and descending the
stem are fully as complicated and interesting as in the case of the
larva. In moving up the stem, the spurs of the last segment are
planted firmly in the wall; the body is then bowed ventrally and
the spines of the dorsal tubercles are brought forward and fixed
in the wall; then by quickly releasing the anal spines, with the
long pointed pygidium of the eighth segment, they and the dorsal
tubercles act as levers and thus propel it up the stem. By executing
these evolutions quickly they can move with considerable rapidity.






8 PAPERS ON CEREAL AND FORAGE INSECTS. i
They can, apparently, descend with equal rapidity. By releasing 'rt
the anal and dorsal spines they are lowered by gravity. If the stem i
be placed in a horizontal position, the pupa makes slow progress j
backward. The organs of locomotion are apparently not so well
fitted for moving backward on a horizontal plane.
THE MOVEMENTS OF THE PUPA OUTSIDE THE STEM.
When removed from the stem and placed upon a flat surface, the: ::
pupa moves as uncertainly as the larva in the same position. It
wriggles constantly, trying in vain to fix its "climbers" into some- *
thing firm, whereby it can gain leverage and propel itself forward. ......
It will fix the anal spines into the surface upon which it rests, but
as there is no surface opposite and near it moves very slowly and
uncertainly...I
THE ADULT.
When ready to issue, the pupa is quite brown. The thin pupal f
envelope is ruptured along the dorsum of the thoracic region and
the insect gradually forces its way out, after which it gnaws an
irregular opening at some point in the stem and emerges.
The adult beetles are about 5 mm. in length, of a brownish color,
and have pointed abdomens. From the lateral aspect they are
somewhat crescent shaped. They are abroad from the latter part
of May to the latter part of June, depending upon temperature con-
ditions in early spring.
There is but one brood or generation during the year.
LIFE CYCLE.
LENGTH OF THE SEVERAL STAGES.
The larval stage covers a period of about 11 months. Nothing
could be learned about the number of molts, as the larvae will not
develop if their galleries are disturbed.
The pupal stage varies from 11 to 16 days, depending, apparently,
upon the temperature.
The adult beetles will live from 5 to 6 days in confinement, but
they will probably survive a much longer period in the open.
HIBERNATION.
The insect hibernates in the larval stage. About the time freezing
begins in the fall the larvae are down to the bulb or crown of the
root, where they are well protected from cold. They are nearly full
grown by this time. Whenever a few warm days come, they appa-
rently start feeding again. In the spring they burrow down into
the juicy bulb, where they continue feeding until they become full
grown.


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


THE TIMOTHY STEM-BORER (MORDELLISTENA USTULATA': LARV.-_ AND PUPA IN STEMS.


PLATE I.





















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THE TIMOTHY STEM-BORER. 9
PARASITIC ENEMIES.
This insect is apparently a very attractive host. Three species
of parasitic Hymenoptera have been reared from it, all of them
new, representing three genera-two braconids and one a chalcidid.
Messrs. H. L. Vierecka and J. C. Crawford b have kindvly described
these parasites, giving them the following names: Heterospilus
mordellistene Vier., Schizoprymnus phillipsi Vier., and Merisus
mordellistenae Crawf. The descriptions appear elsewhere over the
names of their respective authors.
In May of this year, Mordellistena ustulata was found to be very
I abundant at Wilmington, Ohio, in timothy; material was collected
and sent in to the laboratory at La Fayette, Ind., for rearing. Two
species of parasites were reared from it, Heterospilus mordellistene
and Merisus mordellistene. Schizoprymnus phillipsi and Heterospilus
mordellistenw were reared from material collected at Richmond, Ind.,
I in 1906 and 1908, respectively. The latter species and Merisus
mordellistenre were reared at La Fayette, Ind., in 1910.
SIt is very probable that the parasitic enemies keep the beetles
S pretty well in check and that this accounts for the appearance of
I the beetles in small numbers only in any given locality.
REMEDIAL MEASURES.
As this insect has never appeared in destructive abundance, so far
as known, there has been no occasion to devise means of combating it.
S If a serious outbreak should occur, however, a short crop rotation
S should be adopted, allowing a field to remain in timothy sod not
r more than two or three years, thus preventing this stem-borer from
becoming well established. The borders of the fields and waste places
should be mowed frequently during the months of June and July.
If this is done, the larva will not be able to reach maturity.
a Proceedings of the U. S. National Museum, vol. 39, pp. 401-408, 1911.
bProceedings of the Entomological Society of Washington, vol. 12, no. 3, p. 145,
1910.
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