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titaniuH or zinc oxide white-painted rectangle traps that have proven 

 so attractive to sawfly adults ( Fruit Notes 43(1):9-12) are also the 

 most effective for TPB adults. 



Next, we compared this sticky-coated white rectangle trap with 

 other methods of monitoring TPB adults in orchards. Each week from 

 silver tip to petal fall, we examined 25 developing flower buds on 

 each of 12 unsprayed apple trees at Belchertown for evidence of TPB 

 injury. At the same time, we counted the number of TPB adults seen 

 on the 25 buds, and the number collected after making 25 sweeps of 

 the ground cover foliage under each tree with an insect net. Counts 

 also were made of the number of TPB adults captured weekly on a white 

 rectangle trap hung in each tree. 



We found that the number of TPBs captured on the traps each week 

 corresponded very closely to the amount of TPB injury that week. 

 Thus, in weeks where few TPBs were captured, little new injury had 

 occurred. In weeks of substantial TPB captures, substantial new 

 injury had occurred. On the other hand, our counts of TPB numbers 

 observed directly on the buds or taken in net sweeps bore no relation 

 to the level of new TPB injury for the week. 



Our assessment of the occurrence of TPB injury in this test 

 was not as accurate as we would have liked, because whenever it 

 rained, the characteristic droplet of plant sap oozing from the 

 puncture hole was washed away. In such circumstances, many injured 

 buds could be discerned only with the aid of a hand lens to reveal 

 the microscopic puncture. This suggests that in a "normal" Massachu- 

 setts spring, with rainfall once or twice a week, grower reliance on 

 visual examination of buds for presence of oozing plant sap as the 

 sole indicator of TPB injury could be highly misleading. Our experi- 

 ments indicate that use of the white rectangle traps is a much more 

 reliable method. 



Beginning in 1978, we plan extensive studies to relate numbers 

 of TPB captured on the white traps to level of TPB injury. Develop- 

 ment of an accurate trap capture : injury index of TPB should be of 

 real value to growers in making decisions about the need to apply a 

 pesticide spray against TPB. But even in the intervening years before 

 refinement of the index, the white rectangle traps should be useful 

 to those apple growers having a perennial TPB problem: the traps 

 will function as a reliable indicator of the first appearance in the 

 spring of active TPB adults in the orchard. They should also be use- 

 ful to peach growers for this same purpose. 



These white traps, which also effectively serve to monitor sawfly 

 adult activity, can now be purchased from: New England Insect Traps, 

 Colrain, Massachusetts 01340. 



