40 



DECIDUOUS FRUIT IXSECTS AXD INSECTICIDES. 



Table XV. — Time of second-brood larvse of the grape-berry moth leaving berries m 1909: 

 from fruit collected in the field, North East, Pa. 



Date of 



Num- 



Date of 



Num- 



Date of 



Num- 



Date of 



Num- 



leaving 



ber of 



leaving 



ber of 



leaving 



ber of 



leaving 



ber of 



the fruit. 



larvae. 



the fruit. 



larvse. 



the fruit. 



larvee. 



the fruit. 



larvse. 



Sept.22 



11 



Oct. 6 



53 



Oct. 20 



2 



Nov. 3 



6 



23 



21 



7 



50 



21 



9 



4 







24 



15 



8 



40 



22 







5 



1 



25 



19 



9 



38 



23 



5 



6 







26 



8 



10 



50 



24 







7 



1 



27 



11 



11 



24 



25 



7 



8 



7 



28 



16 



12 



14 



26 



13 



9 



3 



29 



21 



13 







27 



1 



10 







30 



12 



14 







28 







.11 



2 



Oct. 1 



12 



15 



2 



29 



4 



12 



4 



2 



73 



16 



1 



• 30 



1 



13 



1 



3 



39 



17 



2 



31 



4 



14 



2 



4 

 5 



3S 



45 



18 

 19 



4 

 



Nov. 1 

 2 



24 

 19 







Total. 



745 



In all, 745 larvse emerged. The table shows that 569, or four- 

 fifths of the larvse, left the fruit in 20 days, from September 22 to 

 October 11, and that the remaining 149, or one-fifth, left the fruit 

 between October 12 and November 14, a period of 34 days, making a 

 total period of 45 days during which second-brood larvae were leaving 

 the fruit. Since the heavy shipment of Concord grapes does not 



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Fig. 12. — Diagram showing cime of leaving the grape berries by second-brood larvse of the grape-berry 

 moth, from fruit collected in the field, North East, Pa., 1909. Daily mean temperature Fahrenheit. 

 (Original.) 



occur until October 1, fruit in infested vineyard areas would have to 

 be removed during the first week of the picking season in order to 

 remove many of the larvse from the vineyard with the crop. 



Figure 12 shows the correlation between the fluctuations of tem- 

 perature and the activity of the mature larvse of the second brood 

 in leaving the grape berries in the fall of 1909. The dotted line 

 represents the daily mean temperature, and the solid line the rate 

 of emergence of the larvae from the berries. It will be observed that 



