June 23. For spray applications only to rows 1 and 2, 

 the tractor was driven outside of row 1 and between 

 rows 1 and 2. 



On June 26, we sampled 100 fruit in each of the 

 seven rows in each plot for signs of any PC injury. 



Results 



Data in Table 1 show that across all three orchards, 

 plot-wide injury to fruit by PC averaged 1.0, 1.1, and 

 3.2% for plots A, B, and C, respectively. Although 

 these values did not differ significantly from one 

 another, injury trends were similar for each orchard, 

 with plot C always showing the greatest injury. 



Conclusions 



Results from this experiment indicate that applying 

 a petal fall spray against PC only to peripheral rows 1 

 and 2 (as in plot C) is unlikely to provide effective 

 orchard-wide control. However, applying a petal fall 

 spray to all rows followed by subsequent sprays only 

 to rows 1 an 2 (as in plot B) appears to be just as 

 effective as applying a petal fall spray and subsequent 

 sprays to all rows (as in plot A). 



Our data from 2003, therefore, suggest the PC 

 behavior and ecology might be slightly different in New 

 England compared with Quebec, possibly due to the 

 colder climate of Quebec. It seems that either more 

 PCs overwinter within orchards in New England than 

 in Quebec or that, prior to petal fall, more PCs move 

 deeper into orchards in New England than Quebec after 



emerging from overwintering sites in woods (see the 

 next two articles in this issue of Fruil Notes for further 

 information on these two questions). Whichever, based 

 on results here, we tentatively recommend that growers 

 apply insecticide against PC to the entire orchard at or 

 shortly after petal fall and spray only peripheral rows 1 

 and 2 in subsequent treatments against PC. 



We recognize that data from trials in only three 

 orchards provide a somewhat thin foundation for the 

 above recommendation. We therefore plan to repeat 

 this experiment in these same orchards in 2004. 



Ackno wledgem ents 



Many thanks to Zeke Goodband, Erick Leadbeater, 

 and Steve Wood for participating in this experiment and 

 to Lupita Trujillo and Mareana Ricci for assistance in 

 sampling. This study was supported by a grant from 

 the USDA Crops at Risk Program. 



References 



Chouinard, G, S. B. Hill, C. Vincent and N. N. 

 Bartakur. 1992. Border row sprays for control of plum 

 curculio in apple orchards. Journal of Economic 

 Entomology S5: 1307-1317. 



Vincent, C, G Chouinard, N. J. Bostanian and Y. Monn. 

 1997. Peripheral zone treatments for plum curculio 

 management: validation in commercial apple orchards. 

 Entomologia Experimentalis Applicata 84: 1-8. 



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Fruit Notes, Volume 69, Winter, 2004 



