Its History, Habits, Food Supply and Life Rate of Increase and Damage Done
to Crops
=History:= The cotton boll weevil is not a native of the United States. It
came from Mexico in 1892. It may have flown across the Rio Grande River
near Brownsville, Texas, or it is possible that it was carried across in
seed cotton. Since 1892, it has extended its range annually from fifty to
one hundred and twenty-five miles until it has spread over Texas,
Oklahoma, Louisiana, Arkansas, Mississippi and a part of Alabama.
=Life and Habits:= The eggs are laid within the squares and bolls of the
cotton plant. The weevil prefers the squares and seldom punctures a boll
as long as there are numerous squares to puncture. The mouth of the adult
weevil is located at the end of the snout. The weevil eats a small hole
into the square or boll and then turns around and deposits one egg in the
puncture and seals the hole with a small drop of a gluey substance to
protect the egg from ants, rain and other destructive agencies. The weevil
seldom deposits more than one egg in a square or boll until the squares
and bolls become very scarce. The egg hatches in from three to fifteen
days, depending on the temperature. The larvae is a tiny white footless
grub, with a brown head and dark jaws. This grub feeds on the inside of
the square or boll and passes into the pupae stage in from six to twelve
days. The adult or mature weevil develops from the pupae stage in three to
ten days and eats its way out of the square or boll.
=How to Know a Boll Weevil:= The safest plan for one who is not well
acquainted with the boll weevil is to send any doubtful specimen to an
entomologist or to a government expert. There are a few characteristics,
however, that will assist anyone in separating the boll weevil from the
numerous other weevils that are often mistaken for it. On each front leg
of the boll weevil are two spines--one somewhat larger than the other. The
snout has a black shining appearance and the "feelers" are near the outer
end. The boll weevil is usually from one-fourth to three-eighths of an
inch long and about half as broad. When they first come from the square or
boll, they are almost pink but rapidly turn darker until they are of a
dark brown or chocolate color.
=Weevils' Food Supply:= The foliage, squares and bolls on cotton stalks
constitute the weevils' sole food supply. The Mexican cotton boll weevil
never feeds upon okra, peas, beans or other plants unless captured and
placed in confinement and then only to a slight extent.
=Rate of Increase:= The weevils that survive the winter begin to lay eggs
when the first squares form on the cotton and successive broods continue
to lay eggs until checked by heavy or killing frost in the late fall.
Observations made by Drs. W. D. Hunter and W. E. Hinds, show that the
female weevil deposits eggs at the rate of from three to five per day and
continues to lay eggs for an average of twenty-eight days. The following
is a quotation from Dr. W. D. Hunter, government entomologist in charge
of the boll weevil work in the South: "A conservative estimate of the
possible progeny of a single pair of weevils during the season beginning
on June 20 and extending to November 4 is 12,755,000."
[Illustration: Larvae of boll weevil in cotton square]
=Life Period of Weevil:= Weevils born during the early summer live from
fifty to seventy-five days. Weevils that are born late in the fall
hibernate and large numbers live through the winter and for about twenty
days after emerging in the spring.
=Hibernation:= The immature weevils in the squares and bolls are usually
killed during the winter. All adult weevils become dormant and the well
protected weevils usually live through the winter and do great damage in
the spring. The adult weevil spends the winter in hedges, broomsedge,
woods, hay stacks, farm buildings, decayed logs, moss and dead trees.