Advancements in Second-stage Apple 

 IPM: Combination of Fruit and Food 

 Odor to Increase Captures of Apple 

 Maggot Flies On Sticky Red Spheres 



Jian Jun Duan, Max P. Prokopy, and Ronald J. Prokopy 

 Department of Entomology, University of Massachusetts 



In recent years we have used 3-inch sticky 

 red spheres baited with synthetic apple odor 

 (butyl hexanoate) to intercept apple maggot 

 flies (AMF) in our pilot second-stage apple IPM 

 program in Massachusetts commercial or- 

 chards. From the results [Fruit Notes 54(1): 1-5; 

 55(l):4-9], we concluded that some improve- 

 ment in the baited sticky sphere system would 

 be needed for such an interception system to be 

 successful on a broad-scale commercial level. 

 One area of potential improvement lay in en- 

 hancing the attractiveness of baited sticky 

 spheres to AMF to ensure capture of a high 

 proportion of immigrants on perimeter trees 

 before they could penetrate into the orchard 

 interior. Previously, we reported the results of 

 several field tests aimed at this goal [Fruit Notes 

 54(4): 18-19]. We concluded that for sticky red 

 spheres, a size of three inches was more visually 

 attractive than larger or smaller sizes. We also 

 concluded that increasing the number of two- 

 dram polyethylene vials containing butyl 

 hexanoate beyond two vials per sphere would 

 not enhance AMF captures on the baited 

 spheres by odor attraction, and that altering the 

 distances between fruit-odor baited vials and a 

 sphere within a range of 6 to 24 inches had no 

 significant effect on fly captures. Besides fruit 

 odor, however, the odor of food (bird feces and 

 insect honeydew) also is attractive to AMF 

 [Fruit Notes 55(3):l-9]. Amajor food-type odor is 

 ammonia, by which AMF are guided to proteina- 

 ceous food. In western North America and east- 

 ern Canada, ammonia has been used primarily 



in combination with sticky yellow rectangle 

 traps to monitor presence of AMF within and 

 near orchards. Sticky yellow rectangles are con- 

 sidered to be visual mimics of foliage eliciting 

 food-foraging behavior. They are much less ef- 

 fective than three-inch sticky red spheres in 

 commercial orchards in eastern U.S. [Fruit 

 Notes 41(6):6-9]. Until now, the combined value 

 of fruit odor and food odor in attracting AMF to 

 red spheres has not been investigated. Here we 

 describe results of recent field tests assessing 

 AMF response to sticky red spheres baited with 

 these two different kinds of odors. 



Methods Used 



Our tests were carried out in 1990 and 1991 

 at Clarkdale Fruit Farm (West Deerfield, MA), 

 which harbored a moderate population of AMF. 

 Using wire, we positioned either two 2-dram 

 polyethylene vials of ammonium carbonate (0.2 

 ounce per vial), two 2-dram vials of butyl 

 hexanoate (0.1 ounce per vial), one vial of each 

 type, or no vial (unbaited control) about 12 

 inches from the side of a sphere. The ammonia 

 was released through a 1/8-inch hole drilled in 

 the vial cap, while the butyl hexanoate was 

 absorbed by and released through the wall of the 

 vial. No more than one sphere was placed in each 

 tree. Tests were conducted from July 7 through 

 19, 1990 and June 23 through August 1, 1991. 

 Periodically, the vials of different treatment 

 types were rotated from tree to tree to minimize 

 the effects of location. At each rotation, spheres 



Fruit Notes, Fall, 1991 



