CONTROL OF GRAPE-BERRY MOTH. 5 
The winter is spent in the pupal stage in cocoons (PL I, fig. 2) 
which the larvae spin in grape leaves the previous fall. These leaves 
are the ones that fall early and become soft and sodden on the ground 
(PL II, fig. 2) and remain under the trellis during the winter. In 
the spring, previous to and during grape bloom, moths (PL I, figs. 
4, 5 ) begin to emerge from the overwintering pupae. This emergence 
gradually increases and continues at a high point for about 3 weeks. 
The moths begin to deposit eggs on the young grapes about 4 days 
after emergence and the eggs hatch in from 4 to 6 days. This first 
brood of larvae or worms usually is not seriously destructive, though 
first-brood infestation amounting to as much as 30 to 35 per cent 
has been observed. The average length of the feeding period of this 
brood of larvae is 23 days. When mature the larvae migrate to grape 
leaves on the vines and spin their cocoons on them. From the cocoons 
moths emerge in about 13 days and begin laying eggs about 4 days 
later. The eggs of this second brood are placed on the nearly full- 
grown grapes and are easily found where the infestation is heavy. 
Before the eggs hatch they appear as creamy-white raised dots on 
the green grape berries, but after the larvae leave the eggs the egg- 
shells appear as glistening white spots. This brood of eggs hatches 
in from 4 to 6 days and it is the resultant brood of larvae that, if 
allowed to develop, does the greatest damage to the grape crop. 
(PL II, fig. 1.) The larvae of this brood feed for a long period and 
usually leave the grapes just before harvest. They spin down to the 
ground and make their winter cocoons on old decayed grape leaves 
under the trellis. In the case of a cold fall many larvae do not leave 
the grapes but are harvested with the grape crop. This condition 
prevailed in the fall of 1917 to an unusual degree and the result was 
a lighter infestation in 1918. 
RELATION BETWEEN SEASONAL-HISTORY DATA AND CONTROL 
MEASURES. 
The control experiments recorded in this bulletin are ,based on ex- 
tensive field observations and on life-history studies conducted each 
season. The data shown in diagram form in figure 1 are sum- 
marized from the complete seasonal-history data. In determining 
the hatching periods of the larvae 4 days are allowed from the 
emergence of the moths to the deposition of eggs and 6 days for in- 
cubation of the eggs. These are average figures from many obser- 
vations extending over several seasons. 
It is seen in figure 1 that in 1916 and 1917 a few larvae had hatched 
before Concord grapes began to bloom and in 1918 that the dates of 
first hatching and beginning of bloom are coincident. In each sea- 
son the first-brood larvae were hatching in large numbers for about 
