capture alighting AMF. Spheres placed on perimeter 

 trees to intercept immigrating adults were accompanied 

 by a blend of five synthetic attractive fruit volatiles 

 contained in a polyethylene vial. Spheres placed on 

 interior trees to monitor adults that penetrated into plots 

 were not baited. All spheres were deployed during the 

 last week of June (before arrival of adults) and 

 remained through harvest (in September). Deployment 

 was at mid-canopy height in a way that maximized visual 

 conspicuousness and attractiveness. 



Index for assigning distances between 

 spheres. The index used for assigning distances 

 between odor-baited spheres on each side of each 

 targeted plot was created by first prescribing a value 

 of 1, 2, or 3 for each of tree size, quality of pruning, 

 cultivar susceptibility, and bordering habitat for that side 

 (Table 1) and then using the sum of the four values to 

 determine distance between spheres (Table 2). Based 

 on previous studies conducted in Massachusetts and 

 Quebec, we chose 6 yards as a minimum distance 

 between spheres and 1 8 yards as maximum distance. 

 Given that this was the first year of using such an index 

 and given that all test blocks were in commercial 

 orchards where valuable fruit was at risk, we were 

 reluctant to deploy spheres at distances greater than 

 18 yards apart. In some cases, the structure of a block 

 (spacing of trees within and among rows) did not allow 

 us to position spheres precisely according to assigned 

 distances. In such cases, we compromised in favor of 

 an assigned distance closest to the original. 



Assessment of treatment performance. We 

 used two methods of assessing treatment performance. 

 First, every other week from trap deployment until 

 harvest we counted and removed all AMF captured by 



eight unbaited spheres placed on interior trees of row 4 

 of baited-sphere plots and by four similarly-positioned 

 unbaited spheres in grower-sprayed plots. Captures 

 by such spheres were used as an indicator of relative 

 numbers of adults that penetrated into interiors of plots. 

 At the same time, we counted and removed all AMF 

 captured by odor-baited spheres on perimeter trees and 

 cleaned all baited and unbaited spheres of insects and 

 debris, re-coating spheres with Tangletrap if necessary. 

 Second, at harvest we sampled 20 fruit on each of five 

 trees on each of the four sides of each baited-sphere 

 and each grower-sprayed plot plus ten fruit on each of 



Fruit Notes, Volume 69, Spring, 2004 



11 



