GRAPE-BERRY MOTH IN NORTHERN OHIO. 9 



The blooming period of grapes from June 21 to July 1 begins with 

 the bloom of the Ives variety, one of the varieties grown commercially 

 in the northern Ohio sections, and ends with the falling of bloom from 

 the Catawba variety, also a commercial variety of importance in the 

 sections studied. It is seen that less than 5 per cent of the total 

 emergence occurred before the beginning of bloom, 50 per cent in the 

 10-day period during bloom, 25 per cent in the next 10-day period, 

 and 21 per cent during the remainder of the season. 



_ _ ._ _ _ 



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Fig. 2.— Diagram showing the time of emergence of spring-brood and fi rst-brood moths of the grape- 

 berry moth at Sandusky, Ohio, 1917. 



A rather close correlation is evident between the rate of emergence 

 and the daily mean temperatures. 



PROPORTION OF SEXES OF SPRING-BROOD MOTHS. 



Table XI. — Proportion of sexes of spring moths of the grape-berry moth, Sandusky, 



Ohio, 1917. 



Sex of moths. 



Number 



of 

 moths. 



Per cent 



of 



sexes. 





305 

 1,116 



43 



21.46 





78. 54 













Total 



1,464 



100. 00 







The high percentage of female moths, as shown in Table XI, seems 

 to account for the frequent heavy infestation by second-brood larva? 

 after a comparatively light first-brood infestation. 



7678°— 20 2 



