The Grape-Berry Moth. Ill 



The summer hrood and its habits. — During July and August all of 

 the four stages of the grape-berry moth can be found in the vine- 

 yards at the same time, for the different broods overlap. What may 

 be termed the second of summer brood of caterpillars works during 

 the latter half of July and in August. 



The July moths or parents of this brood lay their eggs on the skin 

 of the green berries or on the stems.* The embryo caterpillars can 

 be seen through the semi-transparent shell of the egg, as shown in 

 Fig. 16. Several eggs may be laid on the same grape, and are quite 

 easily found. We seem to have been the first to find them. The 

 number of eggs a moth may lay has not been determined, nor the 

 duration of the egg-stage. The European grape-berry moth is esti- 

 mated to lay from 20 to 40 eggs which hatch in about a week. 



A caterpillar which we saw hatch about 5:00 p. m., on July 26, 

 wandered aroimd on the grape-berry for nearly 17 hours, when it 

 finally gnawed its way into the fruit at the point where the stem is 

 attached. It fed inside the same grape until its death August 13, 

 when it was about half -grown. Many of the newly hatched cater- 

 pillars enter where berries touch each other. A dark-reddish spot 

 soon appears on the green fruits around the entrance hole, and as the 

 caterpillar feeds in the pulp this dark spot enlarges until nearly half 

 of the berry is often involved. The young caterpillars are whitish 

 with a blackish head. As they grow, the shield on the thorax and the 

 six true legs become blackish, and the whole body changes to a dark 

 green, often with a purplish tinge (Fig; 18). The caterpillars are very 

 active, and when disturbed quickly wriggle out of the grapes and 

 suspend themselves by a silken thread. 



In our cages, caterpillars which hatched about July 25, got their 

 growth inside the grapes in three weeks and spun their cocoons 

 August 17. Many of the moths developed from this second or sum- 

 mer brood of caterpillars in the grapes emerged from August 15 to 28 

 in our cages. 



The most conspicuous and destructive work of the grape-berry 

 moth is done by this second and most numerous brood of caterpillars 

 working in the growing, green grapes in July and August. Vine- 

 yardists can readily see the characteristic purplish spots on the in- 

 fested fruits, which often crack open at this point (Fig. 13), and thus 

 afford an ideal lodging place for the spores of the destructive rot fungi. 



*The thin, rounded, scale-like, semi-transparent eggs measure .6 to .8 by .7 

 to .9 millimeters in size, and appear whitish in a few days. The shell is finely 

 reticulated, as shown in Fig. 16, and the egg appears to be glued to the fruit by 

 some substance. The egg looks much like a codling-moth's egg, only smaller. 



