12 



BULLETIN" 550, U. S. DEPARTMENT OF AGRICULTURE. 



expected. It might be of use in a garden vineyard or in a commer- 

 cial vineyard where only a small area is infested, but on the whole it 

 can not be regarded as a satisfactory remedial measure. 



EARLY HARVESTING. 



Early harvesting oi grapes and removal of the " trimmings" re- 

 move great numbers of berry-moth larvae which otherwise would be 

 left to overwinter in the vineyard. This practice is limited, for the 

 grape harvest usually continues long after a majority of the berry- 

 moth larvae have cocooned. However, it should be applied to the 

 worst infested areas in the vineyard. 



The degree of reduction of hibernating pupae by comparatively 

 early harvesting is best shown by counting cocoons under vines. 

 During the harvest of 1915, which was an extremely late season, one 

 part of the edge of a vineyard, where the infestation was approxi- 

 mately 50 per cent, was picked October 12 to 15, and all grapes were 

 removed; the other part was picked October 24 to 26. The count of 

 cocoons under 14 vines from each block was as follows: 



Date picked. 



Number of 

 vines. 



Cocoons 



foundunder 



vines. 



Cocoons 

 per vine. 



Oct.l2tolo 



14 

 14 



92 

 621 



6.59 



Oct. 24 to 26 



44.50 







As stated, this was an exceptionally late season. During the sea- 

 son of 1916, according to the records, half the larvae had left the 

 grapes by October 4. Johnson and Hammar found that during nor- 

 mal seasons the majority of the berry -moth larvae left the grapes by 

 October 10. 



Early harvesting is more valuable in avoiding lose of weight in the 

 crop attacked than in reducing the following season's infestation. 

 Grapes badly infested with the berry moth lose weight rapidly after 

 the picking season begins, owing to the movement of larvae from in- 

 fested to sound berries, and to the subsequent shrinking of previously 

 infested berries. 



BURYING HIBERNATING PUP^. 



"Plowing under" the hibernating generation previous to the time 

 of moth emergence and keeping it covered during the earlier part of 

 this period had been practiced for a number of years in the vicinity 

 of North East, Pa., although no definite knowledge as to the effect- 

 iveness of the practice had yet been ascertained. (See Plate IV.) In 

 late fall or early spring earth is thrown up by a plow to the vines 

 on both sides covering the hibernating pupae under several inches of 

 earth.. This earth is allowed to remain until after the general emer- 

 gence of moths in the spring, when it is removed with a horse-hoe. 



