Tabic I, Numbers ol plum cuaulios captured by each type ol Irap m blocks ol unsprayed and sprayed apple 

 trees May I- June 19, 199X 



Trap type 



Number ol replicates 



Unsprayed Sprayed 



Number ol curculios per trap* 



Unsprayed 



Sprayed 



Sticky clear traps at edge of woods 

 Sticky clear traps at edge ot apple trees 

 Sticky green traps at edge of apple trees 

 Sticky black traps at edge of apple trees 

 Black pyramid traps at apple tree trunks 

 Black cylinder traps in apple tree canopies 



Numbers in the same column followed by a different letter are significantly different at odds of 19:1. 



rectangle of plywood painted black to mimic a tree 

 trunk. Each trap was attached vertically to a wooden 

 pole, with trap center 3 feet above ground. The sticky- 

 coated side faced the woods. Each block contained 

 four traps of each type, arranged so that traps alter- 

 nated in type. 



To monitor PCs entering orchard trees by climbing 

 tree trunks, we placed one unbaited black pyramid 

 trunk-mimicking trap (described in the preceding ar- 

 ticle) next to the trunk of each of eight perimeter apple 

 trees bordering woods in each block. 



To monitor PCs present in orchard tree canopies, 

 we placed one unbaited hollow black cylinder twig-mim- 

 icking trap (described in the preceding article) in the 

 canopy of each of the eight other perimeter apple trees 

 (not the same trees having pyramid traps) bordering 

 woods in each block. The black cylinder traps were 

 maintained in vertical position by placing each one over 

 a clipped vertical branchlet about mid-way between 

 the edge and center of the tree canopy and at mid- 

 height of the canopy. 



All traps were emplaced during the pink stage of 

 apple bud development and were monitored twice 

 weekly for eight weeks for captured PCs. On each 

 monitoring day, beginning at petal fall, 1 2 fruit on each 

 of 12 perimeter trees per block were examined for 

 evidence of PC damage. Damaged fruit were allowed 

 to remain on the tree. 



Results 



In the unsprayed blocks of apple trees, significantly 

 more PCs (at least 10 times more) were captured by 

 black pyramid traps next to apple tree trunks than by 

 any other type of trap (Table 1 ). Sticky clear traps and 

 sticky green traps at edges of apple tree canopies, along 

 with black cylinder traps in apple tree canopies, cap- 

 tured about the same number of PCs and significantly 

 more than the sticky clear traps at edges of the woods 

 or sticky black traps at edges of apple tree canopies 

 (Table I ). Despite the large number of PCs captured 

 by the pyramid traps, captures by these traps were not 

 useful in predicting occurrence of PC injury to fruit. 

 Thus, increases in captures by sticky clear traps and 

 sticky green traps at edges of apple tree canopies, but 

 not increases in captures by any other types of traps, 

 were positively correlated with increases in fmit dain- 

 age caused by PCs during the monitoring period. 



In the sprayed blocks of apple trees, there were no 

 significant differences among any of the trap types in 

 numbers of PCs captured, although sticky clear traps 

 at edges of woods and black pyramid traps next to apple 

 tree trunks captured the most PCs numerically, and 

 sticky black traps at edges of apple tree canopies and 

 black cylinder traps in apple tree canopies captured 

 the fewest PCs numerically (Table I). Increases in 

 captures by any of the trap types did not correlate sig- 



Fruit Notes, Volume 63 (Number 3), Summer, 1998 



