rol can be obtained by spraying the trees with DDT.
Apply a spray containing 4 pounds of 50-percent DDT wettable powder per
100 gallons of water (3 level tablespoonfuls per gallon) 30 days before
the first mature nuts are expected to drop, and make two additional
applications at intervals of 7 days. If you are not equipped to spray,
you may obtain some control by treating the soil under the trees with
ethylene dibromide at a depth of 5 inches. Make injections at intervals
of 1 foot in each direction and also in the center of each square formed
by these injection holes. Place 1 milliliter of 40-percent ethylene
dibromide or an equivalent quantity of another dilution in each hole.
Make the application in the fall immediately after the nuts are
harvested and close the injection holes by pressing with the foot. The
soil should preferably be loose to a depth of 5 inches.

The pecan weevil,[10] also known as the hickory nut weevil, often causes
heavy losses of pecans and most species of hickory. Two or three years
are required for the insect to complete its life cycle, but some
specimens reach maturity every year. Adults emerge from the ground from
the middle of July until early in September, according to locality and
seasonal conditions. Injury is of two types--(1) that resulting from
attack before the shell-hardening period in July and August, causing the
young nuts to drop, and (2) that resulting from attack after kernel
formation, the kernel being destroyed by the developing larvae, or
grubs. Egg deposition in the nuts usually begins late in August.

To control this weevil spray the trees twice with 6 pounds of 50-percent
DDT or 40-percent toxaphene wettable powder per 100 gallons of water.
Make the first application when at least six weevils can be jarred onto
a sheet on the ground beneath any tree known to have been infested in
previous seasons, and make the second 10 to 14 days later. The first
application will be needed sometime between the last week in July and
the first week in September. If the soil is hard and dry, it will delay
emergence of the weevils. If you are not equipped to spray, you can
reduce weevil injury about 50 percent by jarring the limbs of the trees
lightly and gathering the weevils on a sheet during the period of
emergence. The dislodged weevils will remain quiet on the sheet long
enough to be picked up and destroyed. Begin jarring about the last week
in July and confine it to two or three trees