Comparison of Traps and Trap Trees 

 for Monitoring Plum Curculios: 

 2002 Results 



Ronald Prokopy, Bradley Chandler, Sara Dynok, Elisa Gray, Matthew Harp, Anne 



Talley, and Jaime Pinero 



Department of Entomology, University of Massachusetts 



In the 2002 Winter issue of Fruit Notes, we reported 

 on year 2001 tests in which we compared odor-baited 

 with unbailed traps of three types (pyramid, cyhnder 

 and Circle) for monitoring plum curculios (PCs) in 

 several commercial apple orchards. All traps were 

 placed beneath or within canopies of perimeter-row 

 apple trees. Results indicated that Circle traps baited 

 with benzaldehyde (BEN, a component of host plant 

 odor) plus grandisoic acid (GA, male-produced 

 aggregation pheromone) captured numerically more 

 PCs than any other baited or unbaited traps. However, 

 no trap type showed even a moderate positive 

 relationship between the time of occurrence of PC 

 captures by the trap (first, second, third, etc. week after 

 petal fall) and time of occurrence of PC injury to fruit. 

 Even for Circle traps baited with BEN plus GA, 

 captures fell off dramatically soon after petal fall, 

 whereas fruit injury rose steadily. Thus, low trap 

 captures after petal fall could not be taken as indicative 

 of a lack of need to spray against PC. 



In the 2002 Fall issue of Fruit Notes, we reported 

 that pyramid traps and sticky-coated Plexiglas panel 

 traps baited with BEN plus GA and placed at orchard 

 border areas were effective in monitoring the seasonal 

 course of immigration of overwintered PC adults into 

 a small unsprayed orchard. This finding suggested that 

 such traps placed in border areas might be useful for 

 monitoring PCs in commercial orchards. 



Finally, in the 2002 Winter issue of Fruit Notes, 

 we reported on a preliminary study in a single 

 commercial apple orchard involving the establishment 

 of odor-baited "trap trees" as a potentially new and 

 effective approach to monitoring PCs. This approach 

 involves baiting the branches of a few perimeter-row 

 trees in an orchard with BEN plus GA and examining 



fruit solely on these few baited trees for signs of fresh 

 PC injury, thereby eliminating the need to examine fruit 

 or a large number of trees to gain an accurate estimate 

 of the degree of current threat of PC injury to fruit. 

 Moreover, a trap tree approach might overcome various 

 shortcomings of odor-baited traps that have afflicted 

 our ability to rely on extent of trap captures as indicative 

 of extent of threat of PC injury to fruit. 



Here, we report results of a 2002 study in 

 commercial apple orchards in which we compared the 

 performance of odor-baited-sticky clear Plexiglas 

 panels and black pyramids (both types of traps placed 

 in orchard border areas) with the performance of odor- 

 baited Circle traps (attached to trunks of perimeter- 

 row apple trees) and the performance of odor-baited 

 perimeter-row trap trees for monitoring the seasonal 

 course of PC egglaying damage to developing apples. 



Materials & Methods 



The three types of traps were: (a) a clean Plexiglas 

 panel (24 x 24 inches) attached vertically at head height 

 to a wooden post, coated with Tangletrap on the side 

 facing the orchard border area, (b) a black pyramid 

 trap (24 inches wide at base x 48 inches tall), and (c) 

 an aluminum-screen "Circle" trap, wrapped tightly 

 around the base of a tree trunk so as to completely 

 encircle the trunk. 



Each trap and trap tree were baited with four 

 polyethylene-vial dispensers of BEN (Aldrich 

 Chemical Company) that together released 40 mg of 

 BEN per day plus 1 dispenser of GA (Great Lakes IPM) 

 that released 1 mg of pheromone per day. Each vial of 

 BEN was suspended inside of an inverted colored, 

 plastic drinking cup to minimize the potential negative 



Fruit Notes, Volume 68, Winter, 2003 



