once during each of 4 weeks in June, beginning when 

 fruit averaged 9 mm diameter and ending when fruit 

 averaged 3 1 mm diameter. Unless indicated otherwise, 

 samphng was accomplished by selecting haphazardly 

 (at approximately head height and m an evenly-spaced 

 manner as possible) 20 fruit from the outer half of the 

 canopy and 20 fruit from the inner half of the canopy 

 of each designated tree. Unless indicated otherwise, a 

 fruit was classified as injured if an ovipositional scar 

 was fresh. Fresh scars were those considered to have 

 been made within the past 7 days (see pictures in the 

 last article m this issue of Fruit Notes). We chose to 

 record only fresh scars because it is the appearance of 

 fresh scars (not older scars) that ought to drive a 

 grower's decision to apply insecticide for PC control. 



Experiment 1 : Amount of Odor. In 1 3 blocks of 

 orchard trees, each having a perimeter row at least 

 225 yards long bordered by continuous woods or 

 hedgerow, we selected nine treatment trees spaced 33 

 yards apart for evaluation of optimum amount of odor 

 to deploy in a trap tree. Four of the trees received one 

 dispenser of GA plus one, two, four or eight dispensers 

 of BEN. Four other trees received two dispensers of 

 GA plus one, two, four or eight dispensers of BEN. 

 One tree remained unbaited. Within each block, 

 treatments were randomized in position. 



Experiment 2: Distance of Response. In 18 

 blocks of orchard trees, each having a perimeter row 



at least 90 yards long bordered by continuous woods or 

 hedgerow, we chose one tree at the approximate center 

 of the perimeter row to be the odor-baited trap tree (no 

 other tree received odor bait). The degree to which 

 ovipositional injury on perimeter-row trees was 

 aggregated on the trap tree was determined by 

 comparing the proportion of sampled fruit injured on 

 the trap tree with that injured on each of four perimeter- 

 row trees to the right and each of four perimeter-row 

 trees to the left of the trap tree. Such trees were 7-9, 

 15-17, 25-27, or 34-36 yards the right or left of the trap 

 tree. 



Experiment 3: Trap Tree Location along 

 Perimeter Row. In 10 square blocks of orchard trees, 

 each having three perimeter rows about 90 yards long 

 bordered by continuous woods or hedgerow, we chose 

 as odor-baited trap trees two comer trees and two other 

 perimeter-row frees midway between and about 45 

 yards from comer frees. We compared incidence of 

 fresh ovipositional injury on comer trees vs. midway 

 trees. 



Experiment 4: Nearness of Injury to Odor 

 Source. In eight blocks of large orchard trees (M.7 

 rootstock), each having a perimeter row bordered by 

 continuous woods or hedgerow, we chose four 

 perimeter-row trees as trap trees. For each of the 32 

 trees, we randomly assigned one quadrant to receive 

 BEN plus GA and the opposite quadrant to remain 



E 5-1 



Q 

 Pi 



z 



z 



< 



4 - 



3 - 

 2 - 

 1 - 







A 



AB 



B 



A 



B 



I I 



1 GA 1 GA 1 GA 1 GA 2 GA 2 GA 2 GA 2 GA 

 10 BEN 20 BEN 40 BEN 80 BEN 10 BEN 20 BEN 40 BEN 80 BEN 



CON 



RELEASE RATE (mg/day) 



Figure 1. Mean percent of sampled fruit on perimeter-row trap trees baited with different 

 amounts of grandisoic acid (GA) and benzaldehyde (BEN) or unbaited (CON) that received 

 fresh ovipositional injury by plum curculio. Means superscribed by the same letter are not 

 significantly different at odds of 19:1. 



10 



Fruit Notes, Volume 69, Winter, 2004 



