applied to both sides of trees of the perimeter (= first) 

 and second row but no insecticide applied to trees of 

 the third through seventh rows (Figure 1). After the 

 petal-fall spray, growers themselves applied 

 azinphosmethyl or phosmet to trees in the eighth and 

 succeeding interior rows and to orchard trees bordering 

 plots on either side. 



Weekly from petal fall until harvest in September, 

 100 fruit in each of rows 1, 3, 5, and 7 of each plot 

 were sampled for injury by PC and AMF. h\ addition, 

 two unbailed sticky red sphere traps were hung toward 

 the center of each row of each plot to monitor AMF. 

 Finally, at harvest, 100 fruit in each of rows 1, 3, 5, 

 and 7 of each plot were sampled for injury by a variety 

 of lepidopteran pests. At the same time, 25 foliar 

 terminals in row five of each plot were sampled for 

 evidence of injury by potato leafhopper. 



Results 



Incidence of each pest type, as averaged across all 

 samples of fruit, foliage or traps in rows 1, 3, 5 and 7 

 of each plot, is given in Table 1. Results show no 



significant differences among any of the four treatments 

 (all-row versus perimeter-row sprays of Guthion versus 

 Avaunt) in incidence of fruit injury by PC, trap captures 

 of AMF, fruit injury by AMF, or fruit injury by summer 

 leafroUers (LR). No injury by internal lepidopterans 

 was found. However, in interiors of plots where only 

 the two perimeter rows were sprayed with Guthion or 

 Avaunt, incidence of foliar terminal injury by potato 

 leafhopper was significantly greater than in plots where 

 all rows were sprayed with Guthion or Avaunt. 



Although differences among treatments were 

 nonsignificant, there was a trend for plot-wide 

 incidence of injury by combined PC, AMF, and summer 

 LR to be less in plots that received all-row sprays than 

 in plots that received perimeter-row sprays: an average 

 of 14% less for Guthion and 21% less for Avaunt (Table 

 1). When injury by these three pests was summed 

 across all-row and perimeter-row sprayed plots, average 

 plot-wide incidence was 12% less in plots treated with 

 Guthion than in plots treated with Avaunt. 



Data on incidence of injury by PC, AMF, and 

 summer LR according to row are given in Figures 2-4. 

 Results for AMF and summer LR suggest that sprays 



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If 



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2 • 



GUTHION; ALL ROWS SPRAYED 



3 5 



ROW 



AVAUhJT: ALL ROWS SPRAYED 



10 



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5 2 



10 



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GUTHION: PERIMETER ROWS SPRAYED 



ROW 



AVAUNT: PERIMETER ROWS SPRAYED 





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Figure 2. Incidence of plum curculio injury to fruit on trees in rows 1, 3, 5 and 7 of plots receiving 

 either Guthion or Avaunt applied to all rows or only to the first two perimeter rows of apple trees in six 

 commercial orchards in MA in 200 1 . 



16 



Fruit Notes, Volume 66, 2001 



