Florida Agricultural Experiment Station


severe and often disastrous, The entire seed crop is sometimes
destroyed. Aside from soil improvement, it is chiefly for the
seeds, or seeds and pods for winter forage that velvet beans are
grown in Florida. They are not generally used as green forage.
Since the plant normally produces much of its growth after late
August or September, the stripping of the vines at that time cur-
tails the soil-improving effect of the crop as well as its seed
production.
 The severity of the infestation varies in different years and
also in different fields and localities. This is due chiefly to the
activities of the insect's natural enemies. In general the severity
of injury increases southward, because the insects get an earlier
start in the southern part of the State.
 The injury is proportional to the size of the field if other con-
ditions are equal. Greater injury occurs in large fields, because
the caterpillars become so numerous that their natural enemies
(principally birds) cannot control them. In a small field, enemies
of the insect come in from the surrounding woods and fields and
usually keep them in check.
 Fortunately the caterpillars do not appear in disastrous num-
bers until August or September in the large velvet bean growing
sections of the State. In October at least, and often in September,
they are brought under complete control by "cholera," a fungus
disease. Consequently it is necessary only to supply a little aid
to the natural enemies at a critical period.
 Few farmers take any measures of control. They trust that
the velvet beans will be able to survive and produce some seed
in spite of the caterpillars. This bulletin is intended to show
that by taking advantage of the food preferences of the cater-
pillar and of its natural enemies, and by the judicious use of
poison, the damage can be reduced to such an extent that velvet
beans will be a dependable crop.
 Altho it is a serious pest, the velvet bean caterpillar can be
controlled at a comparatively low cost. No one needs hesitate
to plant velvet beans on account of the ravages of this insect.

 LIFE HISTORY OF THE INSECT
 The eggs are small white, roundish bodies which are about
one-twelfth of an inch in diameter. (Fig. 13.) The majority of
them are laid on the lower surfaces of the mature leaves. The
egg hatches in about three days. The young larva is about one-
tenth of an inch long. It feeds on the leaves about three weeks,