significantly concentrated on trap trees and were not 

 significantly concentrated on central trees associated 

 with a panel, pyramid or Circle trap. 



Conclusions 



Our findings show that even though panel traps 

 placed in border areas adjacent to perimeter rows of 

 apples trees captured significantly more PCs than 

 similarly-placed pyramid traps or Circle traps placed 

 on trunks of perimeter-row trees, none of these trap 

 types (all baited with BEN plus GA) exhibited amounts 

 of captures that correlated significantly and positively 

 with either weekly or season-long amounts of fresh 

 ovipositional injury to fruit. How can the unsatisfactory 

 performance of these traps be explained? 



In the case of panel and pyramid traps placed in 

 orchard border areas, immigrant PCs may continue to 

 be captured but fail to cause injury because of sufficient 

 residual effectiveness of a previous insecticide 

 application. Indeed, in 13 (=20%) of the 66 instances 

 (6 weeks x 1 1 plots) in which weekly captures of PC 

 adults by panel traps were compared with weekly 

 percentages of freshly injured fruit, at least one PC 

 was captured but no fresh injury was detected. Thus, 

 based on captures by these traps, insecticide might have 

 been applied needlessly. 



In the case of Circle traps attached to tree trunks, 

 we know from our previous studies that when 

 temperature reaches 70 degrees Fahrenheit or more, 

 progressively more adults tend to enter tree canopies 

 by flight rather than by crawling up tree trunks. The 

 wanner the temperature, the greater the probability of 

 PC injury to fruit. In 12 (=18%) of the 66 instances (6 

 weeks X 1 1 plots) in which weekly captures of PCs by 



Circle traps were compared with weekly percentages 

 of freshly injured fruit, 1 % or more of fruit was found 

 injured but no captures occurred At a failure rate of 

 18% to detect injury-causing PCs using Circle traps, 

 such traps can not be recommended for grower use. 



Our new approach of using trap trees baited with 

 BEN plus GA circumvents the above shortcomings 

 associated with use of captures of PCs by panel, 

 pyramid or Circle traps as a guide for degree of threat 

 of damage by PCs and goes directly to the assessment 

 of damage itself. Our findings here indicate that odor 

 baited trap trees established on perimeter rows act to 

 congregate immigrant PCs, resulting in a 15-fold level 

 of aggregation of egglaying injury. No greater amount 

 of orchard-wide PC injury to fruit occurs as a 

 consequence of establishing trap trees than occurs in 

 the absence of trap trees. The establishment of a few 

 trap trees on perimeter rows in an orchard would appear 

 to be a simple and effective way of aggregating PC 

 injury and allowing growers and consultants to focus 

 exclusively on trap trees to gain an estimate of the 

 current status of PC damage to fruit. 



Results of a further 2002 experiment on a trap- 

 tree approach to monitoring PCs are given in the next 

 article in this issue of Fruit Notes. 



A ckn o wledgem en ts 



We are grateful to the following growers for 

 participating in this study: Keith Arsenault, Gerry 

 Beime, Bill Broderick, Dave Chandler, Don Green, 

 Tony Lincoln, Joe Sincuk, Mo Tougas, and Steve Ware. 

 This work was supported by funds from a USDA 

 Northeast Regional EPM grant, a USDA Northeast 

 Regional SARE grant, and a USDA Crops at Risk grant. 



it it it ^ it 



10 



Fruit Notes, Volume 68, Winter, 2003 



