38 BULLETIN 911, U. S. DEPARTMENT OP AGRICULTURE. 



Second-brood larvae begin to leave the fruit early in the fall, 

 August 22, 1916, August 15, 1918, September 7, 1917, but leave in 

 greatest numbers just previous to and during the earty part of the 

 harvest season. In 1916, 77 per cent of the larvae left the fruit 

 previous to the beginning of the Concord harvest and 90 per cent 

 previous to the beginning of the Catawba harvest. In 1917 corre- 

 sponding figures were 56 per cent and 94 per cent. 



In each brood of moths the females occur in much larger number 

 than the males, the proportions being 21 per cent males, 79 per cent 

 females in the spring brood, 1917 ; 18 per cent males, 82 per cent females 

 in the summer brood, 1917; 25 per cent males, 75 per cent females 

 in the spring of 1918; and 21 per cent males and 79 per cent females 

 in the summer brood of 1918. A small part of the first-brood larvae 

 do not transform to moths the same season but hibernate and emerge 

 as moths the following spring. In 1918 this amounted to 5.9 per cent 

 of the total number recorded. Of the same lot of larvae but 1.4 per 

 cent were parasitized. 



Mating and egg deposition were observed during these investiga- 

 tions. The habit of the grape-berry moth larvae of feeding on grape 

 leaf galls formed by the grapevine phylloxera was noted. Extreme 

 resistance of the larvae to low temperature was also noted, live larvae 

 persisting after a minimum temperature of 17° F. had occurred. 

 Parasitism was very low and of little consequence as a control during 

 these investigations. 



Control measures recommended are cultural methods which will 

 leave the overwintering pupae exposed to the elements as much as 

 possible. Satisfactory control was effected by two spray applica- 

 tions by the "trailer" or hand method of spraying. The first appli- 

 cation should be made 3 to 5 days after the young grapes set and the 

 second when the grapes first touch in the clusters. 



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