10 BULLETIN" 911, U. S. DEPARTMENT OF AGRICULTURE. 



PERCENTAGE OF EMERGENCE OF SPRING MOTHS. 



Table XII. — Percentage of emergence of spring moths of the grape-berry moth from 

 hibernation under a leaf blanket in insectary yard, Sandusky, Ohio, 1917 . 



Lot No. 



Source of material. 



Number 



of 

 cocoons. 



Number 

 of moths 

 emerged. 



Emer- 

 gence. 



1 





2, 082 

 1,493 

 2,371 



82 



780 



236 



231 



12 



Per cent. 

 37.46 



2 





15 80 



3 





9 74 



4 





14 63 





Total ! 







6,028 



1,259 









20.88 













No explanation is offered for the variations in percentages of 

 emergence from material collected at the different places. The ma- 

 terial was all collected as larva? in the infested grapes at similar 

 times and kept under identical conditions after collection. That but 

 20 per cent of the cocoons formed withstood the winter under a light 

 leaf blanket indicates that the natural mortality is considerable. 



TIME OF DAY OF MOTH EMERGENCE. 



Records were taken as opportunity offered on the time of day of 

 moth emergence. These records were in the period July 8 to July 

 17 or about in the middle of the emergence period. They indicated 

 in a general way that emergence began in the morning as soon as the 

 heat of the day was felt and that practically all emergence took place 

 between 6.30 a. m. and noon. 



OVIPOSITION BY THE SPRING BROOD OF MOTHS. 



A few records of oviposition were secured and are shown in Table 

 XIII. These meager records serve only as an indication of the actual 

 conditions prevailing. 



Table XIII. — Oviposition of spring moths of the grape-berry moth in rearing cages, 



Sandusky, Ohio, 1917. 





Number of 

 moths. 



Date of — 



Days— 



Observation No. 



3 



? 



Emer- 

 gence of 

 moths. 



First ovi- 

 position. 



Last ovi- 

 position. 



Before 

 ovipo- 

 sition. 



Of ovi- 

 posi- 

 tion. 



From 

 emer- 

 genceto 



last 

 ovipo- 

 sition. 



1 



2 



4 



10 

 10 

 12 

 11 



June 18 

 June 27 

 July 18 

 July 20 

 July 23 



June 21 

 July 2 

 July 21 

 July 22 

 July 24 



June 24 

 July 2 

 July 23 

 July 26 

 July 28 



3 

 5 

 3 

 2 

 1 



4 

 1 

 3 

 5 

 5 



6 



2 



3 



4 



5 



10 



4 



I 



5 

 5 

 6 

 5 





2.8 



3.6 



5.4 















