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consistent trend was that holding off treatment until petal fall resulted in 

 very little reduction in injury. Even so, the best treatments (tight cluster 

 during 1981-1983 and half-inch-green or early pink during 1984-1986) reduced 

 fruit injury by only about 50% compared with unsprayed check trees. This 

 situation was true even though the pesticides used (Ambush", Pydrin", or 

 Cygon") were among the most effective known against TPB. 



Conclusions 



We conclude that conducting research on the time of initiation of TPB 

 injury to fruit in apple orchards and the time at which it is most efficacious 

 to apply pesticide for TPB control is no less frustrating than attempting to 

 manage TPB effectively in commercial orchards. Examination of 11 years of 

 pesticide trial data of numerous researchers in the eastern United States and 

 Canada reveals a truly incredible amount of variation from locale to locale and 

 from year to year within a locale in the effectiveness of any given material in 

 preventing TPB fruit injury. Our 11 years of sampling fruit at harvest in 

 commercial orchards throughout Massachusetts reveals an equally large variation 

 in TPB injury and in success at controlling TPB. The data presented here on 

 tests conducted in the same experimental orchard over 6 consecutive years 

 likewise are fraught with a high degree of variation, the causes of which are 

 uncertain. In fact, the picture we now have of how to control TPB effectively 

 is nearly as unclear as when we began these tests in 1981. It seems to us no 

 wonder, therefore, that growers have a difficult time dealing with the insect. 



If we can conclude anything from the research reported here and from 

 observations we and others have made in commercial orchards, it is this. 

 First, initiation of TPB fruit injury may occur any time from tight cluster 

 through petal fall. Second, populations of TPB in commercial orchards may be 

 sufficiently great at any time from tight cluster to petal fall to cause 

 considerable fruit injury. Third, visual monitoring traps have proven over the 

 years to be sensitive in determining if TPB populations are sufficiently great 

 to merit possible pesticide application. Fourth, materials such as Cygon" and 

 pyrethroids are probably the most effective sorts of materials against TPB, 

 though their use in no way guarantees good control. Finally, if used, 

 pesticide should be applied against TPB sometime between half-inch-green and 

 late pink. But, based on the data reported here, we would not want to predict 

 what the outcome might be. Perhaps, as Rick Weires of the Hudson Valley Lab 

 and we have pointed out several times, we should be paying less attention to 

 TPB and more attention to factors such as bruising and mechanical injury to 

 fruit during harvest and grading. In virtually every Massachusetts orchard we 

 and others have sampled over the years, bruising, stem punctures and mechanical 

 injury have been responsible for far more culls (average of 29 bushels per acre 

 per year) than TPB and all other insects combined (average of 3 bushels per 

 acre per year) . 



•k "k rk "k :k 



