Ideal Within-canopy Positioning of 

 Odor-baited Red Spheres for 

 IVIonitoring or Control of 

 Apple Maggot Flies 



Sara Hoffmann, Isabel Jacome, Everardo Bigurra, and Ronald J. Prokopy 

 Department of Plant, Soil, & Insect Science, University of Massachusetts 



About 20 years ago, we conducted tests aimed at 

 establishing favorable positions within canopies of apple 

 trees for deploying unbaited sticky red spheres to 

 capture apple maggot flies (AMF). We found that 

 removal of all foliage and fruit within 10 to 20 inches of 

 a red sphere resulted m greater AMF captures than 

 allowmg foliage and fruit to encroach within 3 mches 

 of a sphere or removing all foliage and fruit within 40 

 inches of a sphere. Since the time of this initial study, 

 researchers at the New York Agricultural Experiment 

 Station in Geneva have developed a blend of synthetic, 

 attractive apple volatiles that draws AMF toward blend- 

 baited trees and enhances captures of AMF by red 

 spheres deployed in blend-baited trees. 



Here, we report on expenments conducted in 2002 

 and 2003 aimed at defining favorable positions within 

 apple trees for deployment of blend-baited red spheres 

 for capturing AMF. We asked three questions. First, 

 we asked which distance between a baited red sphere 

 trap and the nearest foliage and fruit gave rise to the 

 greatest AMF captures. Second, we asked which part 

 of the tree canopy (outer half or inner half) was the 

 more favorable for positioning a baited red sphere trap 

 to maximize captures. Finally, we asked whether the 

 distance to which foliage and fruit were cleared away 

 from a red sphere trap was of greater consequence to 

 trap performance when traps were baited or when 

 traps were not baited. For each question, we examined 

 effects of season on the pattern of AMF response to 

 traps. 



Materials & Methods 



All experiments were conducted in a city-ov^ned 

 apple orchard in Leominster, Massachusetts dedicated 



to honor Johnny Appleseed (a.k.a. John Chapman, who 

 was bom in Leominster). We used Jersey Mac trees 

 on M.26 rootstock, which had a moderate amount of 

 fruit each year. We also used Golden Delicious trees 

 on M.7 rootstock, which also had a moderate amount 

 of fruit each year. All trees involved in our trials were 

 moderately well pruned and received periodic season- 

 long treatments of fungicide to protect against apple 

 diseases. They received insecticide treatments through 

 May to protect fruit against early-season insect pests 

 but none thereafter. 



Each year, we conducted two experiments: one 

 using Golden Delicious trees, the other using Jersey 

 Mac trees. There were not enough trees of either 

 cultivar to conduct both experiments each year using 

 the same cultivar. 



Spheres used as traps were wooden, 3.5 inches in 

 diameter, and coated with Tangletrap to capture 

 alighting AMF. When baited, a sphere received a single 

 polyethylene vial containing a five -component blend of 

 synthetic attractive apple volatiles positioned about 6 

 inches to the side of the sphere. Each year, spheres 

 were deployed in mid-July and remained in place until 

 rmd-September. Each tree received ^ single sphere hung 

 at head height. 



Our first question was addressed in 2002 using 

 Golden Delicious trees. Foliage and fruit were cleared 

 to one of five distances (in a radius) around spheres: 0, 

 10, 20, 30, or 40 inches. For the 0-inch treatment, 

 clearance was just enough to prevent foliage and fruit 

 from touching the sphere. All spheres were odor-baited 

 and hung in the outer half of the tree canopy. There 

 were six replicates of each treatment. 



Our second question was addressed in 2002 using 

 Jersey Mac trees. Odor-baited spheres were deployed 



Fruit Notes, Volume 69, Spring, 2004 



15 



