6 
BULLETIN 83*7, U. S. DEPARTMENT OF AGRICULTURE. 
3 weeks. It is important to note that the rise in the early part of 
the hatching is abrupt and the subsidence of hatching more gradual. 
It has been the opinion of other writers that the largest part of 
the second-brood larva? hatch within a shorter period of time than 
the first brood. The rearing records here illustrated do not support 
that belief but show the hatching periods to be of about equal 
length. 
NATURAL CONTROL OF FIRST-BROOD LARViE. 
It was observed that the grape berries infested by first-brood 
larvae dropped readily from the vines when touched. It was thought 
that if these infested berries dropped in any great numbers at any 
particular time some cultural method such as covering these berries 
with soil might aid in the control of the insect. To determine this 
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Fig. 1. — Diagram showing relation between dates of spray application and periods during 
which the grape-berry moth larvae were hatching for the seasons 1016, 1917, and 191S 
at Sandusky, Ohio. 
point the following experiment was undertaken in 1916: Wooden 
frames were made, 6 feet long, 30 inches wide, and 6 inches deep 
with cheesecloth stretched on the bottoms. These trays fitted be- 
tween the vines directly under the trellis and were placed in six 
different locations in the vineyard, under vines heavily infested with 
first-brood larvae. Fresh leaves were supplied in the trays for the 
cocooning of any larva? that might drop. The trays were put in 
place July 5 when first-brood infestation was about at its height 
and were left until August 15. when practically all first-brood larvae 
had left the grapes. These trays were examined every three days. 
Practically no grapes dropped from the vines and not a single larva 
was taken throughout that period. From these negative results it is 
concluded that practically no natural control occurs from the drop- 
ping of grapes infested by first-brood larvae. 
