hange to
pupae the following summer. This weevil has a one-year cycle, or one
generation a year.

The life history of the small chestnut weevil[9] is somewhat similar,
except that in the vicinity of Beltsville the weevils leave the soil
late in May or early in June, when the trees are in bloom. Several weeks
later the females deposit eggs in the nuts. At Beltsville, egg laying
begins late in August and continues for several weeks. After the nuts
have fallen from the tree, the full-grown larvae leave them and enter
the soil. Earthen cells are constructed at a depth of 4 to 12 inches,
where some of the larvae remain for two winters.

The small chestnut weevil completes its life cycle in two years, and a
small percentage requires three years, whereas the large chestnut weevil
completes its transformation from egg to adult in one year. The large
weevils pass the winter as larvae, whereas the small weevils pass one
winter as larvae and the second winter as adults. With the few
individuals of the small weevil which require three years for
transformation, the first two winters are passed in the ground as larvae
and the third in the same location as adults. This habit of the small
weevil complicates control measures, as one season's spraying with DDT
does not reduce the entire infestation of weevils.

[Footnote 8: +Curculio proboscideus+ Fab.]

+Proper Time for Spray Applications+

Application of DDT sprays at the proper time is very important. An
examination in 1944 of many unopened chestnut burs disclosed the fact
that eggs of the small chestnut weevil were being deposited many weeks
before the burs would open. It was also noted that great numbers of the
larvae were leaving the nuts soon after the burs cracked open. Evidently
these full-grown larvae had hatched from eggs deposited several weeks
before the burs split.

In 1945, 1946, and 1947, cloth bags were tied over developing burs at
various intervals during the season to prevent further egg laying in the
nuts. At harvest time, the bags were removed and the nuts examined.
Occasionally adults were hidden among the spines of the burs and were
inadvertently enclosed in the bags; therefore, all nuts in bags
containing female adults that might have continued ovipositing were
discarded. The data in Table 1 show the approximate time prior to which
the nuts were infested.

Because of difficulty in obtaining sufficient burs for bagging, and
other orchard conditions, the