CONTROL OF THE GRAPE-BERRY MOTH. 5 
have left the berries. However, in the very late autumn of 1915 the 
majority of the larvae did not leave the berries until after October 25. 
Winter is passed in a cocoon, usually spun in a decayed grape leaf 
under the trellis. (PL III, fig. 2.) 
FEEDING HABITS OF LARVAE. 
The very few early larvae which hatch before the grape blossoms 
fall feed in the blossom cluster. But most of them, coming after the 
grapes are set, eat at once into the berry, causing the characteristic 
purple spotting and cracking of grape berries. 
The point of entrance may be anywhere on the surface of the 
grape berry, but before the berries touch, about half of the larvae 
enter around the stem attachment. Of 500 infested berries counted 
on July 14, 1916, about 12 days after setting of grapes, 266 were 
entered at the stem end and the other 234 from other parts of the 
grape berry. After the grape berries reach the stage of growth 
where they begin touching, the point of contact becomes the most 
common place of entrance. 
The early larvae, which hatch when the grape berries are still small, 
destroy many more berries than do larvae which hatch after the grapes 
are larger. 
FLIGHT OF MOTHS. 
The distance which moths of this species may fly in large numbers 
is uncertain, but as a rule the spread of infestation is slow. In one 
instance serious infestation advanced from a heavily infested vine- 
yard into an adjacent young vineyard not more than 100 or 120 feet 
distant. In this vineyard there could have been no previous infes- 
tation, as it had just come into bearing. Some infested berries were 
found 350 feet from the older vineyard, but very few. On the other 
hand, the following season a vineyard about 1,100 feet wide, newly in 
bearing, was traversed and infested heavily by a single generation. 
The spreading of infestation probably is much influenced by weather 
conditions at the time of the flight of moths. While it may be slow 
ordinarily, no vineyard is immune from rapid infestation in a vicinity 
where the berry moth is present. 
HISTORY OF CONTROL METHODS. 
Measures to control the grape-berry moth, since its appearance as 
an economic pest, have developed gradually from many sources. 
The first considerable advance toward a solution of the problem, 
however, was made by the biological and systematic studies of 
Slingerland (9) 1 and Kearfott (8) in which they definitely de- 
termined the limits of the species and the fact that the grape was 
its only food plant; and by Slingerland's field experiments, which 
i Reference is made by number to " Literature cited/' p. 42. 
