LEAFLET No. 4
The Pecan Weevil
THE pecan weevil is one of the most important insect pests of
pecans in central and northern Alabama. Although it is
present in practically every county of this state, it apparently
is not a serious pest in southern Alabama along the coast. In
groves in the central part of the State it has caused the loss of
as high as 80 per cent of the entire crop of Schleys.
Description of the Stages of the Pecan Weevil
The adult weevil resembles the cotton boll weevil, but is much
larger and has a longer beak. It is brown or greyish-brown,
and about three-eighths of an inch long. The beak of the male
is slightly shorter than the body, and is used to puncture and to
feed upon the immature nuts. The beak of the female is longer
than the body, and can puncture even the hardened pecans for
feeding and egg deposition (Fig. 1).
The eggs are oval, greyish-white, and slightly less than one-
sixteenth of an inch long. They are placed inside the kernel
of the pecan nut by the female weevil which usually lays three
eggs in each nut.
The larvae are white when small but change to a creamy-
white color upon becoming full grown. Their heads are red-
dish-brown. Full grown larvae vary from one-fourth to one-
half inch in length.
Seasonal History
The adult weevils emerge from the soil from the last few
days of July until the first of September. They immediately fly
to pecan or hickory trees and begin to feed upon the immature
nuts. The punctured nuts fall to the ground within four to
ten days and often constitute a large majority of the August
"drop."
As soon as the nut kernels pass the watery stage and harden,
the female weevils begin to lay eggs in the nuts. No eggs are
layed in any variety while the kernels are watery. Egg deposi-
tion usually begins during the last week in August or the first
week in September. The actual date depends upon the time
of hardening of the pecan nut kernels. A single female may
lay as many as one hundred eggs, but the average number laid
AGRICULTURAL EXPERIMENT STATION
OF THE
ALABAMA POLYTECHNIC INSTITUTE
M. J. FUNCHESS, Director
AUBURN
JULY 1934
is about twenty-five per female. A hole is bored with the beak
through the hull and shell and each egg is placed within the
kernel of the nut. The eggs hatch within seven to ten days,
depending on the temperature, and small legless larvae (or
worms) come out. The small larvae feed upon the kernel of
the pecan until full grown. This requires two weeks or more.
The full grown larvae may then gnaw a hole through the side
of the nut and drop to the ground. or they may remain within
the nut several months after harvest.
Larvae emerge from the nuts during the latter part of Sep-
tember and throughout ()ctober and November. enter the soil
to a depth of three to nine inches, and remain there for from
one to two years. They then pupate from the middle of Sep-
tember to the middle of ()ctober and transform into the adult
stage withiu apl)lroximately three weeks. These adults remain
within the soil until the following August, when they emerge
and begin to feed upon the nuts. The cmpnilete life cycles re-
quire two( and three years.
Varieties Attacked
The Ipecan weevil will feed and lay eggs on any variety of
pecan, but the damage is most severe 
upon the Schleys and
Stuarts. When these varieties are not available, considerable
damage may be done to Success and Van I)emans.
F IRE - F(nI II p . ( iI I I L - 1, t c n
Extent of Damage
Where the crop is light and the weevil infestation heavy,
the feeding of the adults may result in the loss of the entire crop
due to the dropping of the punctured nuts. Even when a large
crop is set, the damage is usually heavy.
Each female requires from ten to thirty or more nuts in which
to deposit her eggs, and where large numbers of weevils are
present, practically the entire crop at harvest may be wormy.
Control
Control measures are usually unnecessary except upon trees
of the Schley and Stuart varieties.
Jarring.-The adult weevils have the habit of "playing
dead" or "sulling" when the limbs upon which they are resting
are slightly jarred. They relax their hold, fall to the ground,
and remain motionless for several minutes. This habit can be
utilized in the control of the pecan weevil.
Picking sheets should be placed under the spread of the
branches of the trees. Each limb should then be jarred sharply
two or three times, either from the ground by the use of a padded
pole or, in the case of higher trees, by climbing the tree and
jarring each large limb with the foot. Heavy shaking is neither
necessary nor desirable, and the jarring should not be severe
enough to shake off the nuts. The weevils should then be picked
up from the sheets and dropped into buckets containing a small
amount of kerosene.
Trees should be jarred at least once a week beginning the
second week of August and continuing for four or five weeks,
or as long as weevils are found in the grove. Results are some-
what better if jarring is done during the cooler parts of the day
when the beetles are least active.
For large top-worked trees, the cost of each jarring 
will
amount to approximately six cents per tree, or from fifty to sixty
cents per season.* Where trees are headed lower and may be
jarred from the ground, or where farm labor may be used, the
cost will be much less. A saving of from three to six pounds
of nuts will pay for jarring.
Destruction of Worms. in Nuts.-Nuts containing worms re-
tain their husks long after the normal ripe nuts have opened.
Where the pecan weevil infestation is especially bad, the nuts
should be gathered as soon as they are ripe enough to be easily
beaten out of the husks. All nuts should then be knocked from
the trees and those with clinging husks should be separated from
*These figures for jarring on a commercial scale were furnished by the Lanett Mills,
Lanett, Ala., from records kept by Mr. J. 0. Roquemore, manager of the company's
pecan grove.
4
the good nuts. Some of these nuts with clinging husks should
then be examined by cutting them open to see whether or not
they contain worms. If over 5 per cent are wormy, the nuts
should be placed in racks with quarter mesh wire bottoms. These
racks should be placed in chicken houses having tight board or
concrete floors. The larvae which emerge from the nuts will
fall through the screen to the floor and may be eaten by chickens
or turkeys. Nuts should be moistened occasionally and left in
these racks until the following February. The few good nuts
present may then be sorted out and the remainder discarded or
burned.
It should be remembered that not all nuts with clinging husks
contain pecan weevil larvae, as this same condition may be caus-
ed by other insects and diseases and by various physiological
disturbances.
While this method will greatly reduce the number of worms
entering hibernation, it cannot be relied upon alone for their con-
trol as large numbers of larvae often leave the nuts before
harvest.
DEPARTMENT OF ZOOLOGY-ENTOMOLOGY
H. S. SWINGLE, Associate Entomologist