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lo. 99. Issued March 6, 1908.

SB : :
818 nited States Department of Agriculture,
ay BUREAU OF ENTOMOLOGY.

L. O. HOWARD, Entomologist and Chief of Bureau.

THE NUT WEEVILS.‘
By F. H. Currrenpen, Sc D.,
Entomologist in Charge of Breeding Experiments.

INTRODUCTION.

Nut-growing in the United States would be a much more profitable
industry were it not for the insects which inhabit the kernels, render-
ing them unfit for food. This is especially true of the chestnut and
chinquapin and to a lesser extent of pecan, hickory, and hazel nuts;
while others, which include butternuts, walnuts, and almonds, suffer
little or no injury from this source. Considerable diminution in the
vield of many forms of nuts is also caused by the inroads of insect
larvee in the growing husks. Examples of the first class are the chest-
nut “ worms” or weevils; of the second, the husk-worms and walnut
curculio. The present paper will be restricted to a consideration of
the weevils. .

The chestnut crop suffers the greatest loss, and the chief depredators
are the grub-like “ worms” or larve with which everyone is too dis-
tressingly familar. These larve develop with the nuts, so that those
which first attain maturity are ready to leave and enter the ground
nearly as soon as the nuts
are gathered; others re-
main in the nuts some
weeks later; so it fre-
quently happens that
when nuts are packed
for shipment in bags or

barrels, some nuts which Fic. 1.—Chestnuts showing exit holes of chestnut weeyil
were apparently sound larve. Enlarged one-fourth (author’s illustration).
when shipped are found, on reaching their destination, with one or
more holes in their shells (fig. 1), while the repulsive grubs crawl
about at the bottom of the receptacle. How to cope with these weevils
has long been a most vexatious problem.

Tue Cuestnut WEEVILS.

In comparatively recent years chestnut culture has assumed consid-
erable proportions, and has taken a new impetus since the extensive
introduction and development of Japanese and European varieties.
These are grafted on American seedlings or native stocks, and thus
many valueless trees on equally unpromising soil are converted into

@Reprinted from Yearbook of the Department of Agriculture for 1904, pp.
999-310, Pls. XX VIII-XXX, text figs. 17-26.
[Cir: 99]

; 2

sources of profit. Were it not for the * worms,” “ borers,” and
“ blights,” chestnut growing might develop into a most lucrative in-
dustry in regions adapted to it.

EsTimMatTes or Losses.—A fair estimate of the damage done annually
by weevils to chestnuts grown in the United States would probably
fall little short of 25 per cent, while in some years the percentage
exceeds that figure, running as high as 40 or 50 per cent. Growers
in some localities report no damage, others place losses as low as 5
or 10 per cent, while instances are cited of whole crops being de-
stroyed. The amount of loss is dependent on locality, season, and
to a more limited extent on the variety of nuts grown. The greatest
damage is usually incurred in regions where chestnuts have grown
wild for many years, and the least where there are no wild chestnuts
or chinquapins and the nuts are grown only for market and are care-
fully gathered. The most extensive losses, judging from available
sources of information, appear to be in Massachusetts, Pennsylvania,
New Jersey, New York (in the vicinity of New York City), Delaware,
Maryland, Virginia, Tennessee, and North Carolina.

In Georgia, Spanish and Japanese varieties have been cultivated for
years without attack by weevils being noticed. In New Jersey, 50 per
cent of the same varieties have been ruined. A grower in Missouri
has reported no damage to 50 trees of an American variety; another
at South Haven, Mich., has reported no injury for a period of three
or four years to Japanese and Spanish chestnuts grown there, while
from 5 to 20 per cent of the crop of native nuts was annually de-
stroyed. The nearly complete destruction of the chestnut crop of
New Jersey for 1893 was reported.

THE SPECIES OF CHESTNUT WEEVILS.—The species of weevils which
infest chestnuts are two in number—the larger chestnut weevil, Bala-
ninus proboscideus Fab., and the lesser chestnut weevil, B. rectus Say.
They have extremely long, slender beaks or snouts, nearly as fine as a
horsehair, and considerably longer than the body in the female. By
means of this long beak the female is able to penetrate the thickest burr
of the chestnut with its long spines and to cut out, with the minute and
sharp mandibles at the tip of her beak, a little hole for the deposition
of hereggs. These are inserted through the husk into the growing nut.

The two species resemble each other greatly in color and in mark-

ings, the general color of both being golden yellow, ochraceous, or clay
yellow, frequently tinged with olive, and a little paler on the lower
surface. The disk of the thorax is a little darker, with a wide bright
band on each side, and the elytra, or wing-covers, are mottled with
rich ight brown or dark brown markings of variable size and extent.?

“ Occasional individuals lack the darker markings, some being paler, others darker, even
reddish. The ground color, as may be seen in abraded specimens, is really black, and the
apparent color is due to seales very similar to those of butterflies and moths.

[Cir 99]

3

THE LARGER CHESTNUT WEEVIL.
(Balaninus proboscideus Fab.)

The larger chestnut weevil (fig. 2) is considerably the larger and
more robust species. The female rostrum or beak, although proportion-
ately of about the same length
as in the lesser weevil, is per-
ceptibly more prominent be-
sause less curved, the curvature
being toward the tip. It is
also more widened at the base.
The body measures from one-
third to nearly one-half of an
inch in length, and the beak
of the female is often five-
eighths of an inch long. That
of the male (fig. 2, ¢) is nearly
as long as the elytra. The ’
egg is small, about one-six- Fic. 2.—The larger chestnut weevil (Balaninus probos-
teenth of an inch Jong, and of {ie} female beete: 2 me tn outing, trom
the outline shown in figure times natural size (author’s illustration).

3,d. It is nearly white, partially translucent, and without sculpture.

, The larva (fig. 3, a) is
milk-white, robust, fully
three times as long as wide,
with the dorsal or upper
portion rounded and _ con-
vex. The entire surface is
very strongly wrinkled
; transversely, and there are
Fic. 3.—Larger chestnut weevil (Balaninus proboscideus): g few very short hairs scat-

a, Larva; b, c, female pupa; d, eggs. All enlarged (au- ig A

thor’s illustration). tered sparsely over the dif-
ferent segments. The head (fig. 4) is about one-fourth as wide as
the widest portion of the body. It is provided with
short but strong mandibles, by means of which it gnaws
the kernel constituting its food. The fully developed
larva in ordinary resting position measures nearly half
an inch. Although the larva has no true legs, it is able
to crawl, slowly and clumsily, it is true, by means of ay
of the flattened lower surface, locomotion being aided jg. 4 paraninus
by transverse wrinkles. proboscideus:

The pupa is of a clearer whitish color than the larva, ae ane
and shows the principal external organs of the body of — iustration).
the future beetle, all, except the beak, folded tightly to the body.
The female pupa 4s illustrated in figure 3, 0, c.

[Cir. 99]

4

This species, like the other weevils under consideration, is native to
America and is known from Rhode Island to Virginia, the District of
Columbia, southern Ohio, and Tennessee, and westward to Kansas.
The geographical distribution of this and the other nut weevils has as
yet not been carefully studied, but in all probability it is considerably
more extensive than above stated.

In some regions this species is quite generally known as the chin-
quapin weevil, but the investigations conducted during 1904 indicate
that, although it breeds in chinquapins and more commonly in chest-
nuts, it occurs in greater abundance in the larger imported nuts.

THE LESSER CHESTNUT WEEVIL.
(Balaninus rectus Say.)

The lesser chestnut weevil (fig. 5) has the scape of the antenna
longer than in the preceding species and the first joint longer than
the second. The average
length of the body is about one-
fourth of an inch, but the size
varies, as in all of these insects.

The distribution of this
species extends from Canada
and Massachusetts to North
Carolina, Tennessee, and Ohio,
and probably farther west-
ward. The writer has seen sets
of specimens labeled * Arizona.”

Although in some localities the

Medica ncamet ge etnies fete Jarger species is much more in

view; ¢, head of male. Much enlarged (author's evidence, taken all in all, the

ees lesser weevil is the more com-
mon and is probably even more widely disseminated.

The egg has not come under observation, but is undoubtedly very
similar to that of the preceding, being proportionately smaller, which
isstrue of the remaining stages.

The larva is only a third of an inch long and its length is about
three times its width. The body is milk-white and the head light
brownish yellow, while the A-mark has a short lateral branch each
side.

The pupa differs from that of the larger species by size and by
characters shown in figure 6, which illustrates the male.

“In the larger species the first joint (omitting the scape) is shorter than the
second. In the female rectus the rostrum is strongly curved, the thorax is
longer than wide, and the elytra are strongly acuminate apically. The tooth
with which the thighs are armed is small, with the entering angle rounded.

[Cir. 99]

5)

LIFE HISTORY OF BOTH SPECIES.

The life history of our two chestnut weevils is so similar as to be
practically the same for both species. There are, however, minor
differences. These, as well as related nut and acorn weevils, hibernate
exclusively in the larval condition and in the soil. Both make their
first appearance at about the same time—with the first blooming of
chestnuts—but this period may vary from late in June to July,
according to locality and season, or, more properly speaking, the
mean temperature. At this time the beetles are found rarely and
scatteringly, and as oviposition has not been observed then it is
doubtful whether it begins until considerably later. What function
these early arrivals fulfill is problematical. The beetles increase in
number as the nuts approach maturity, or until about the middle of
September or a little time before the nuts are first marketed. Then
they may be seen in greater abundance, several pairs, frequently of both
species, often occurring on a single bunch
of burrs (fig. 8). As it requires about two
weeks for the egg to develop, it is not prob-
able that they are laid much earlier than
when the nut begins to form. From exam-
ination of many burrs gathered in the fall
of 1904 by Mr. F. C. Pratt, of the Bureau
of Entomology, who visited some of the
principal chestnut groves of Pennsylvania e peo Parsan macnn bar
and \ irginia at the urgent request of grow- side. at Jefi? ventral wiewsat
ers in those States, it is deduced that the right. Enlarged (author’s

2 F illustration).
first eggs deposited are laid (seldom and
very sparingly) in the soft, woolly material surrounding the forming
nut; but later they are inserted in the kernel just under the inner
skin, and occasionally they are deposited somewhat more deeply. In
no case has the egg been found in the outer husk.

Eggs are laid singly, but many are placed in a single nut, as high as
40 or more (of the smaller weevil) in imported nuts, and as many as
9 in native nuts. The larvae when hatched feed on the tissue of the
growing kernels, enlarging with their own growth the cells thus made.
When, as is usual, several larve inhabit the same nut, the interior is
more or less completely hollowed out, and large masses of excrement
are left behind (fig. 9).

By the end of September or the first week of October the beetles dis-
appear. At about the same time, when the nuts first fall, the larve he-
gin to mature and issue from round orifices which they gnaw through
the shell and which vary in diameter from one-sixteenth of an inch, in
the case of the smaller species, to one-eighth of an inch in the larger
(see fig. 7). By the size of these holes alone it can be readily deter-

mined which species is the dominant one in any given locality. Rarely
[Cir. 99]

6

larve bore through the burr. On leaving the nuts they burrow into
the earth to depths varying from 2 to about 8 inches, according to the
hardness of the soil. If confined in soft earth or sand they penetrate
still deeper. The larval period probably lasts from three to five weeks
in the nuts, and about ten months in the earth, pupation taking place
within three weeks of the issuance
of the beetle, the latter remaining
several days in the earth before
appearing above ground.

The beetles do not fly readily, but
cling tightly to their resting place
or drop when disturbed; yet, as
their bodies are not heavy and their
= wings strong, they are obviously
Fig. 7—Chinquapins, showing injury by les able to cover considerable distances,

pene Wea eee nee aan especially with thecwimde 9 Ondingr
ght. Enlarged (original).
rily, however, they are sluggish,
like most other weevils, and probably do not go far from the vicinity
of the trees which have sheltered them as larve, although they
undoubtedly migrate when food is scarce.

NATURAL ENEMIES.

A natural enemy of the nut weevils is known, a small four-winged
wasplike fly, the braconid parasite Urosigalphus armatus Ashm.,
which develops in the body of the larva.‘

METHODS OF CONTROL.

The most practical remedy for nut weevils that can be suggested is
the early destruction of the ‘“ worms” in the nuts by means of bisul-
phid of carbon and the observance of clean orchard management and
other cultural methods. It may be well to preface the discussion of
these methods with a statement of the uselessness against nut weevils
of ordinary measures employed in the control of similar insects.

UNSATISFACTORY METHODS.

Sromacu porsons.—The peculiar structure, in the nut weevils, of
the mouth-parts (minute mandibles placed at the end of a beak nearly
as fine as horsehair and as long or longer than the body) is almost
sufficient proof in itself that these insects do not feed on leaves, but
depend for sustenance on the substance of the growing nuts. The
beetles first appearing feed on the undeveloped, very young nuts and
the juices within the husk. There is, therefore, no seeming possibility
of reaching them with a spray of Paris green or other stomach poison,

“Pwo other insects are associated with the weevils and are probably also
their enemies, a proctotrypid parasite, T'richasis rufipes Ashm., and a predatory
reduviid bug, Acholla multispinosa DeG.

Cir. 991

“N

Larger chestnut weevil on chinquapin burrs. Twice natural size (original).

Bre. 8:
fiCir: 99)

1—Parry’s

Fic. 9.—Imported nuts, showing different forms of injury by nut weevils.
Giant nut, showing exit hole of Balaninus proboscideus ; 2—Same of B. rectus: 3—
Interior of Paragon nut, showing larve of B. rectus in situ; 4—Same, showing work of

one individual of B. proboscideus ; 5—Reverse side of figure 2, showing scars made by
puncture of female B. rectus in ovipositing ; 6—Reverse of figure 1, with puncture of
B. proboscideus. All natural size (original).

[Cir. 99]

9

particularly as we are unable to place the insecticide where they
would eat enough to kill them.

Trap crops.—The cultivation of special varieties of nuts with a
view to securing immunity from attack or as a means of luring the
insects from the main crop does not offer any degree of promise. The
Paragon, Cooper, and Ridgeley varieties, according to Mr. G. H.
Powell, of the Bureau of Plant Industry, suffer greater loss from
weevil attack than Japanese varieties. Chinquapins are favored by
the smaller weevil and suffer far more damage, as a rule, than wild
chestnuts. It is possible that the planting of the varieties specified,
or, better, of chinquapins, at intervals around, as also through,
orchards of the least affected varieties might lessen the loss to the
main crop. Ifa variety could be produced which would mature fruit
before the advent of the beetles in greatest numbers, this would
partially solve the problem, particularly as the earliest nuts bring
the highest prices. The nuts gathered toward the end of the season
are comparatively uninjured, but by this time the market value is
considerably lower.

ConTAcT poIsoNns.—Scarcely more can be expected from the use of
contact poisons, such as kerosene emulsion, since in view of the long
period spent by these weevils in the adult stage (from June and July
to September or October) such frequent application would be neces-
sary that the expense would destroy the profit.

JARRING THE TREES, as practiced against the plum curculio, is for -
the same and other reasons equally impracticable, save, perhaps, on
young trees grown in a small way.

THE WATER TEST OF INFESTATION.—Having doubts of the efficacy of
this old-fashioned test of the difference between “ wormy” and
healthy nuts, an experiment was made by the writer with native
chestnuts obtained from a street vender. To begin, 40 per cent were
obviously “ wormy,” and only 60 per cent apparently sound.

Results of water tests with native chestnuts.

a ~ > =

Nuts which rose to surface. | Nuts which remained on bottom.
: | Per cent. Per paint
Wimindesteds:=-=- 2 4 kes Se 88 oe kee | 10) | In) perfect condition=-422 22-2225 -2= 40 |
Showing minute marks only; good | Slightly;injured22.5--2= =e 30
faVOresalAple west e otha | 20' | Badlvuintestedes- 2.2 =ae oe aa eee 20 |
Containing full-grown grubs____.___ 10 | Completely filled with grubs_______- 10
Containing immature grubs_________ 60 |

As will be seen from this experiment, noticeably wormy nuts, as
evidenced by loss of weight and the exit holes of the ‘“ worms,”
naturally rise when placed in water, but the remaining nuts may or
may not be infested, and hence require further test than whether
they will sink or float.

[Cir. 99]

10

Direct REMEDIES,

BIsuLPHID ©Ff CARBON.—The value of bisulphid of carbon as a fumi-
gant for chestnuts infested by weevils is now fully established.
Although at first thought it would seem difficult for the gas to pene-
trate through shells so firm and compact and kill the larvee, neverthe-
less a prominent grower in Pennsylvania successfully uses the bisul-
phid, applying it when the nuts are first harvested. The dead weevil
larve are at this time so small that the average person would never
detect their presence, while if they were permitted to develop they
would soon destroy the nut for food. Bisulphid of carbon has been
used on the largest chestnuts grown in this country, and, since a score
or two of larve find shelter in a single nut, one can appreciate the
desirability of prompt fumigation. The grower mentioned uses
bisulphid of carbon at the rate of 1 ounce to a bushel of Paragon nuts
placed in a kerosene barrel of about 50 gallons capacity and covered
by sacking. After an exposure of about sixteen hours the nuts are
removed, the larve being then practically all destroyed. Several
hundred pounds were treated in 1904 in this manner with perfectly
satisfactory results. To verify reported results, Mr. Pratt was
detailed to visit the infested orchard and witness the process. This
method could be employed at less expense by using tightly fitting
covers, the effectiveness of the fumigation being in exact proportion
to the tightness of the receptacle and the length of exposure to the
fumes. Therefore, a longer exposure of one or two days, with per-
haps one-half ounce of bisulphid, should accomplish the same purpose.

SCALDING AND DRYING.—Some growers make a practice of plunging
the nuts as gathered into boiling water just long enough to kill the
contained insects and yet not injure the nuts for sale, after which
they are dried before being marketed. This may be profitably accom-
plished by using a large sieve, which is filled with nuts, dipped in the
water, and removed in about five minutes. The late W. P. Corsa
used a washtub, in which was placed a bushel or so of nuts, pouring |
in enough boiling water to come an inch or two above the nuts.
Then, by stirring vigorously with a stick, the bulk of the weevilly
nuts would come to the surface in the same manner as do peas and
beans affected by weevils.t. The infested nuts are skimmed off and
destroyed, or they may with profit and safety be fed to hogs, pro-
vided the animals do not have a too exclusive diet of this form of
food. Salt water, it is claimed, is preferable for scalding, the brine
serving to keep the shell soft and pliable and rendering the kernels
more palatable than when not thus treated.

Different methods are employed in drying. A good way is to place
the nuts in the sun and agitate them occasionally by stirring or

“Note the writer’s observations on this head on p. 9.

[Cir. 99]

iba

shaking in a bag until thoroughly dry, because if moisture remains
unevaporated it is apt to form mildew when the nuts are prematurely
packed for shipment.

Nuts for planting should not be scalded, and care should be taken
not to cook the kernels of nuts intended for sale. Some growers
claim that the hot-water treatment is objectionable because the nut-
shells lose a certain degree of polish, rendering them less desirable
for market. |

Heat.—Infested nuts can be subjected to a-temperature of be-
tween 125° F. and 150° F. without injuring them for food or for
seed, and this will effect the destruction of the larve within. Some
growers of chestnuts destroy the weevils by kiln-drying.

Coip sroracr.—Cold storage has been employed and is successful
in arresting the development of the larve. The appearance of the
nuts is scareely different from that of those not so stored, but nuts
thus treated and submitted to the writer after becoming dry were
deficient in flavor, having an acrid and moldy taste.

A crude form of cold storage has been successfully followed by a
Virginia grower. It consists in placing nuts in the earth under the
shade afforded by his house, where the soil temperature, after the
nuts are gathered, does not exceed 50°. Since most insects are inac-
tive below 51° this has the effect of restraining their development,
causing the eggs or minute larve to die.

PREVENTIVES.

CHOICE OF LOCATION FOR THE oRCHARD.—The selection for the
planting or grafting of chestnuts of a locality with reference to the
chances of immunity from injury by nut weevils is a matter of great
importance. For this reason it is most undesirable to plant in the
immediate vicinity of woodland abounding in wild chestnut and chin-
quapin, since these trees furnish natural breeding places for the in-
sects, and are, therefore, a constant menace to successful chestnut
culture. Too frequently growers suffer losses from weevils because
they neglect to gather the wild chestnuts or chinquapins in the im-
mediate vicinity of their cultivated groves. Another phase of bad
management which is frequently practiced is the grafting of culti-
vated varieties on native chestnuts growing in rocky and uneven soil,
often on hillsides, as shown in figure 11. In such places it is impos-
sible to harvest a complete crop, and, what is of equal importance, to
gather the remnants. Hence, to secure these results, it is impera-
tive to plant or graft trees on smooth ground (fig. 12), first for the
sake of economy, and second to permit the collection of all of the
nuts, leaving none for the propagation of weevils. It is also neces-
sary to keep the soil clean of herbage, as shown at the left of fig-
ure 12—not overgrown with brush, as illustrated at the right.

[Cir. 99]

12

CAREFUL HARVESTING.—It is always advisable to gather the entire
crop, leaving none on the ground, and either place the nuts in tight
receptacles or fumigate with bisulphid of carbon before marketing.
The grubs crawl out soon after the nuts have been gathered, and as
they require considerable moisture they will die if confined in closed
barrels or boxes. The trouble is that enough nuts are usually left in
orchards or in adjoiming wood or forest land to serve for the propaga-
tion of the insects the following year. In order to make the methéd
of treatment here described thorough, it will be necessary to secure the
cooperation of neighboring landowners who grow chestnuts for mar-
ket and of all who own woodland containing chestnut and chinquapin.

The collection of remnants can be made by children or the unem-
ployed. It is also profitable to allow hogs the run of the orchards to
destroy what nuts remain after the crop has been harvested. In the
mountainous sections of Virginia and Pennsylvania’it is a common
practice to fatten swine on the unpicked fallen nuts. Hogs fatten on
nuts and acorns as well as on corn, and without expense to the grower.

Coorrration.—The results of the observance of clean farming on
the lines that have been indicated may not at once be apparent, but in
course of time, if this work is systematically carried out by all grow-
ers over a considerable territory, infestation will be very materially
decreased. An important point is to ascertain how far the insects
fly. Their structure indicates that they are strong fliers and capable,
with favoring winds, of migrating considerable distances; but under
ordinary circumstances they probably do not fly many miles at a
time or in a given year.

Tue Pecan WEEVIL.
(Balaninus caryxe Horn.)

With the increase of pecan culture in our southern States frequent
inquiry is made in regard to the cause of the holes in the nuts
(fig. 10), and during
1903 and 1904 there
were reports of great
injury of this nature,
more particularly to
pecans grown in Texas,
where considerable loss
was reported, and in
Georgia, where in one
locality 75 per cent of
the crop was a failure.
A shortage has also
been reported in Mis-
sissippi. ‘The insect involved in these cases is the pecan or hickory-
nut weevil, a pest which is evidently destined to become one of the

[Cir. 99]

-_

TESA OSE

Seg ee :
Fic. 10.—Pecan nuts showing exit hole of pecan weevil larve.
One-third enlarged (author’s illustration).

13

Fic. 11.—Paragon chestnut orchard, growing on hillsides, showing impossibility of clean
orchard management.

Fic. 12.—Paragon chestnut growing on plane surface, where clean methods of cultivation
can be practiced.

[Cir. 99]

14

principal drawbacks to the cultivation of the pecan. Indeed, in many
parts of the South it already divides that distinction with the husk-
worm, so that it has been truthfully said that what the husk-worm
leaves the weevil destroys.

The beetle (fig. 13) is about the same size as the larger chestnut
weevil, from which it may be distinguished by its much duller color 4
and by the relative lengths of the first and second antennal joints, the
first joint being longer than the second in the pecan-infesting species.

The larva differs from that of proboscideus in being decidedly yel-
low, having the head bright
red and wider than long. Its
cervical plate also is darker.
The pupa is similar to that of
the larger chestnut weevil.

The distribution extends
from New York to the Gulf,
and westward at least to Iowa.

The life history of this wee-
vil, as it occurs in the pecan
in the South, is, so far as can
be gathered from reports from
Fra. 13.—Pecan weevil (Balaninus caryse): a, Female, Georgia and Texas and from

dorsal view ; b, same, lateral view, in outline; J|aboratorv experiments, very

c, head with rostrum and antenna of male. About A 4 ie: :

two and onchalf times natural size (authors Similar to that of the chestnut

ifustrabien). weevils. According to the ob-
servations of Mr. H. A. Halbert, at Coleman, Tex., the female begins
to deposit her eggs in August while the pecan is still immature, and
the larva usually escapes from the nuts in the latter part of Septem-
ber and in October; but most of them do not issue until the husks
open, allowing the nuts to fall. In Georgia they have been found in
the nuts as late as the middle of January.

REMEDIES.

The same care in the selection of the site for a pecan orchard is
advised as in the case of chestnut culture, with this difference, that the
grower should avoid planting in the vicinity of wild pecan and hick-
ory of whatever kind. The entire crop, also, should be harvested or
hogs should be turned in to devour what nuts are left. At Thomas-
ville, Ga., Mr. Wilmon Newell observed in 1904 that where swine and
chickens had had access to a pecan grove, the ground was well rooted
and ser@tched up and there was less loss from weevils than in the pre-

“The ground color is uniform dark brown, nearly black, and the scaly covering
(which characterizes the chestnut weevils) in this species is hair-like on the
thorax, fine and somewhat sparse on the wing-covers, and much duller, with
little or no mottling. Moreover, the beak of the female is, comparatively, a little
shorter, although of about the same curvature, and is less widened at the base.

[Cir. 99] :

15

vious year. Evidently both hogs and poultry devour the larve in the
ground.

At the time that bisulphid of carbon was first suggested as a remedy
for chestnut “ worms ” it was feared that the firm and compact shell
would hardly permit the gas to penetrate and kill the contained larvee.
Experience, however, has shown that this remedy is successful in the
case of chestnuts, and it is not impossible that it might be adapted to
pecans, using a larger amount of the chemical and a longer exposure
in a perfectly tight receptacle. We can as yet scarcely advise this
method on a large scale, but it should certainly be tried experimentally.

Tue Hazetnut WeEEvIiL.
(Balaninus obtusus Blanch. )

Hazelnuts or filberts are injured in much the same manner as are
chestnuts and pecans and by a similar weevil. Injury was recognized
as early as 1841, but was attributed to
other species than that under considera-
tion. Owing to the comparatively slight
importance of the hazel as a nut tree in
this country, few notices of losses from
weevil attack have been recorded. The
weevil which affects the nut was not
differentiated from others of its kind
until 1884. In 1891 it was reported as
badly damaging hazelnuts in Iowa.

The beetle (fig. 14) differs from others
which attack edible nuts, exclusive of Fic. 14—Hazelnut weevil (Balaninus
acorns, by its shorter, more robust form = (cau) RGults @ Rien Pe ae.
and shorter beak.t It is about one- male from side. Enlarged (original).
fourth of an inch in length, and the
beak does not exceed half the length of the body. The vestiture
varies from gray to ochreous, and the elytra are moderately mottled.

This species occurs from Massachusetts and New Hampshire west-
ward to Minnesota and Texas. Injury has been noted in Massachu-
setts, New York, Indiana, Iowa, and Minnesota.

Of the life history little has been recorded beyond the fact that the
“worm ” issues from the side of the nut, and that paired adults have
been found on hazelnuts in July.

REMEDIES.

Since hazels are not cultivated in this country to any extent, no rem-
edy need be employed other than gathering entire crops and destroy-
ing isolated bushes where it is unprofitable to gather the nuts. It
would be quite possible, owing to the small size of the hazel plant, to
control this species by jarring, as for the plum curculio.

@The appendices of the claws are broadly rectangular, and the femora or thighs are
armed with large teeth. The scape of the antenna in the female is long.

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