GRAPE-BERRY MOTH IN NORTHERN OHIO. 



13 



The average length of the feeding period is seen to be 20.62 days, 

 the maximum 37 days, and the minimum 14 days. The records 

 extended throughout the regular hatching period, and therefore 

 reflect vineyard conditions closely. 



LENGTH OF THE PREPUPAL PERIOD OF FIRST-BROOD INDIVIDUALS. 



In Table XVII are given the dates of cocooning and the length of 

 the period from the time of spinning the cocoon until pupation for 

 individuals some of which were supplied with sprayed foliage and 

 others with unsprayed foliage. 



Table XVII. — Time of cocooning and length of prepupal period of 231 individuals of 

 the first brood of the grape-berry moth, Sandusky, Ohio, 1917. 



Number of 

 - cocoons. 



Foliage unsprayed : 



Dates of cocooning — 



August 3 50 



August 4 50 



August 5 50 



August 7 39 



August 8 34 



Foliage sprayed : 



August 7 40 



August 8 24 



Dates of pupation. 



Number of pupae by days. 



Aug. 4 



17 



26 



3 















5 



7 



28 



7 













6 



21 

 18 

 1 











7 











8 



21 



14 



1 



1 

 18 

 11 



2 

 11 



7 



3 





9 





10 







2 



11 







5 



.12 











6 



13 













1 





















46 



4 



42 

 8 



40 

 10 



36 

 3 



30 

 4 



23 



17 



14 











Table XVIII. — Summary of Table XVII. Length of prepupal period of 231 indi- 

 viduals of the first brood of the grape-berry moth, Sandusky, Ohio, 1917. 



Number individuals. 



Prepupal 

 period. 



Cocooned on unsprayed 

 foliage. 



Cocooned 



on sprayed 



foliage. 



67 

 104 

 23 



2 

 13 

 12 



6 



4 



Days. 

 1 

 2 

 3 

 4 

 5 ' 







194 



37 







Average 1.77 



Maximum 3 



Minimum 1 



2.9 

 5 







1 







