CONTROL OF THE GRAPE-BERRY MOTH. 

 Experiment in the Moorhead Vineyard, Moorheadville, Pa., 1915. 



11 



A plat of 22 rows, comprising nearly 3 acres, part of which had been 

 hand picked in the experiment in 1914, was chosen for experimental 

 work. No difference in infestation was shown in the two parts 

 of this plat, probably because the effect of the work of the previous 

 season had been obscured by the flight of moths from one part to 

 another. However, the cumulative results probably were of con- 

 siderable value, as the infestation in this section of the vineyard was 

 much lighter than it had been the previous season, while the infesta- 

 tion of the vineyard as a whole was about the same. 



The plat was hand picked only once for infested berries, between 

 July 30 and August 5, the time required being lengthened by rain. 

 The actual labor required .was 43 hours. 



Counts taken just before harvest on 12 representative vines in the 

 hand-picked plat and in the check plat showed the following results : 



Table 3. — Counts in hand-picking experiment, Moorhead vineyard, North East, Pa., 1915. 



Plat. 



Number 

 of vines. 



Number 



of 

 clusters. 



Number 



of 

 berries. 



Infested 

 berries. 



Infested 

 berries 

 per 100 



clusters. 



Infesta- 

 tion. 





12 

 12 



408 

 360 



11, 793 



11, 793 



945 

 1,677 



242.3 

 465.8 



Per cent. 

 8.01 



Check 



14.22 







Discussion. 



An average, from the different experimental plats, of the time re- 

 quired to hand pick the "wormy" berries in an acre of grapes was 

 55.75 hours. At 12^ cents per hour the cost per acre would be $6.97. 



This method, hand picking wormy berries, was employed in a num- 

 ber of vineyards by the owners during the seasons of 1914 and 1915 

 and as a rule the beneficial results were not readily apparent. In 

 several instances the value of the work was reduced by picking the 

 berries after most of the "worms" had left the grapes, and in others 

 by inefficient laborers who missed a large percentage of the "wormy" 

 berries. In some cases the infestation probably was considerably 

 reduced and in one instance apparently successful control resulted. 

 In this vineyard the infestation was restricted to a narrow strip com- 

 prising a few rows which were hand picked by the owner himself 

 about once a week. 



From the experiments and observations of the two seasons, hand 

 picking of "wormy" berries could be relied upon to reduce berry- 

 moth infestation but not to control it The difficulty of securing 

 ample and efficient labor at a time when it is needed stands in the 

 way of adopting hand picking as a general method of repression, and 

 the ultimate cost is thus too high when only partial control may be 



