impact of ultraviolet light on the stability of BEN. Vials 

 of BEN were not renewed during the course of our test 

 but dispensers of GA were renewed once (after 5 

 weeks). Dispensers of BEN and GA were suspended 

 from the bottom edge of panel traps and from the 

 branches of trap trees. For pyramid and Circle traps, 

 dispensers of BEN were suspended in such a way that 

 the open bottoms of the protective drinking cups were 

 4 inches above the inverted screen funnel (that capped 

 each trap) to reduce close- range repellency of BEN, 

 and the dispenser of GA was placed inside of the screen 

 funnel. Four plots were established along a continuous 

 132 yard section of a perimeter row of apple trees in 

 each of 1 1 commercial orchards. Each plot was 33 yards 

 long by 7 rows of trees deep and contained one of the 

 four trap treatment types. Traps or trap trees were 

 positioned midway along the 33 yard length of the 

 perimeter row of a plot. Panel and pyramid traps were 

 placed in orchard border areas, 7 yards from the near 

 edge of the canopy of the central perimeter-row tree of 

 a plot. Circle traps and trap trees were assigned to the 

 central perimeter-row tree of a plot. 



Traps and trap trees were installed at the pink stage 

 of bud development (April 22-24) and remained for 

 10 weeks (June 24-26). Weekly beginning at petal fall 

 (May 13-15), we counted and removed all PCs from 

 traps and examined 

 100 fruit per plot on 

 perimeter trees for 

 evidence of fresh PC 

 egglaying scars. In 

 all, 20 fruit were 

 sampled on the 

 central perimeter- 

 row tree (directly 

 opposite a panel or 

 pyramid trap or 

 containing a Circle 

 trap or functioning 

 as a trap tree) and 20 

 fruit were sampled 

 on each of two 

 evenly-spaced trees 

 to the right and again 

 to the left of the 

 central tree. Fresh 

 scars were those 

 considered to have 

 been made within 



the past 7 days. It is the appearance of fresh scars (not 

 older scars) that ought to drive a grower's decision to 

 spray against PC. 



Each grower applied three sprays of 

 azinphosmethyl or phosmet to control PC in the plots. 



Results 



Across the entire season, panel traps captured 

 significantly more PCs than either pyramid or Circle 

 traps (Figure 1). Even so, for none of these three trap 

 types was there a significant positive correlation 

 between total captures of PCs per plot (across all weeks 

 from petal fall through June) and mean percent of 

 sampled perimeter-row fruit per plot exhibiting fresh 

 egglaying scars (across all weeks from petal fall 

 through June) (Figure 2). 



Furthermore, for none of the three traps types was 

 there a significant positive correlation between sample- 

 week trap captures per plot and sample-week percent 

 of penmeter-row fruit per plot having fresh egglaying 

 scars (Figure 3). A significant positive correlation 

 would indicate that a week during which comparatively 

 many trap captures occurred also was a week in which 

 a comparatively large amount of fruit was injured by 

 PC, whereas a week during which comparatively few 



T3 



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k_ 



3 

 Q. 



u 

 (/) 

 O 

 Q. 



c 

 re 



Panel 



Pyramid 

 Season-long captures 



Circle 



Figure 1. Season-long captures ot overwintered plum curculio adults by odor-baited 

 panel, pyramid and Circle traps placed in association with plots of perimeter-row 

 apple trees. Means superscribed by the same letter are not significantly different at 

 odds of 19:1. 



Fruit Notes, Volume 68, Winter, 2003 



