orchard to a series of pesticide sprays to ensure that maggot fly popula- 

 tions were not building up over successive years within the orchard- 

 There are 3 elements in the non-pest icidal program of apple maggot 

 control in California: 



(a) Use of sticky red spheres hung in apple trees to capture the flies 

 and thereby prevent (or greatly reduce) egglaying (see Fruit Notes 

 50(2):2-5); 



(b) Twice-weekly removal of drops from beneath the trees to prevent 

 larval exit from any infested fruit; and 



(c) Refrigeration or processing of tree-harvested fruit to prevent 

 larvae from maturing into pupae. 



No one of these elements alone is likely to completely prevent apple 

 maggot buildup within an orchard. Together, they ought to work as well as 

 frequent pesticide treatments. 



A principal point of debate over the efficacy of this non-pest ic idal 

 approach has been the frequency with which dropped apples must be picked up 

 to prevent any larvae from emerging and forming pupae in the soil. Because 

 picking up infested drops constituted the first line of defense against the 

 apple maggot until earlier this century, a good deal of work was conducted 

 on this subject by pioneering apple maggot researchers such as J.F. 

 Illingworth of Cornell, W.C. O'Kane of New Hampshire, and W.H. Brittain and 

 C.A. Good of Nova Scotia. It is this work that gave rise to the recommen- 

 dation that an effective schedule of drop pickup should be twice per week. 

 In recent decades, however, little or no research has been carried out along 

 these lines. Thus, we decided to initiate 3 small experiments to determine 

 if the findings of the pioneering workers were still valid. 



In the first test, we placed 5 wire baskets (18 x 30 inches) under each 

 of 3 unsprayed Early Mcintosh trees (an early-season variety) on Orchard 

 Hill in Amherst. The baskets were in place from June 15 (before any maggot 

 flies were mature) until August 8 (the date by which all but a handful of 

 fruit had fallen). Every 3-^ days, we collected each fruit that dropped 

 into the baskets and examined it carefully for presence of an exit hole made 

 through the fruit skin by an emerging larva. After examination, we put the 

 drops in wire baskets beneath non-fruiting trees and thereafter examined 

 them for exit holes every 3-^ days until all had completely rotted. 



The results (Table 1) show that of the ^24 dropped fruit collected over 

 the course of the season, only 2 (0.5%) showed a larval exit hole on the day 

 of drop pickup (0 to 3 or 4 days after drop), and only one additional fruit 

 (0.2%) showed a larval exit hole when examined 3-k days after drop pickup (3 

 or 4 to 7 days after drop). Each of these 3 fruit had fallen at least 2 

 weeks after the optimum time for fruit harvest (July 8). (Note: in this 

 abandoned orchard optimum harvest was about 1 month earlier than in commer- 

 cial orchards.) In addition to examination of drops, 25 on-tree fruit were 

 sampled every 3-4 days from July 8 - August h for larval exit holes. None 

 was found. However, one fruit that had dropped and was caught in a crotch 



