exposed wooden PTS, 100% of AMF died (Table 4). 

 This result indicates that the 4% (a.i.) amount of 

 imidacloprid in latex paint on the surface of wooden 

 PTS remained highly effective in killing AMF after 12 

 weeks of exposure to sunlight and 7.31 inches of 

 rainfall. 



After 6 weeks of field exposure from mid-August 

 until late-September, sugar/flour PTS that were 

 deployed in mid- August killed 58% of alighting AMF 

 (Table 4). When a 20% sugar solution was applied to 

 these spheres, 87% of AMF died (Table 4). 



Conclusions 



Populations of AMF were substantially greater in 

 2001 than in 2000 in commercial apple orchards in 

 Massachusetts. In 2000, wooden PTS topped by fluted- 

 type sugar/wax discs were slightly superior to sugar/ 

 flour PTS in controlling AMF in commercial orchards. 

 In 2001, as described here, wooden PTS topped by 

 reservoir-type sugar/wax discs were substantially better 

 in preventing AMF penetration of commercial orchard 

 blocks and preventing injury to fruit than were sugar/ 

 flour PTS. Indeed, wooden PTS were just as effective 

 as 2-3 sprays of insecticide in providing effective AMF 

 control in 2001. 



In 2001, sugar/flour PTS experienced about the 

 same level of damage by rodents and other mammals 

 as they did in 2000: 35-47% of sugar/flour PTS 

 received 20% or more damage by such vertebrates after 

 6 weeks of orchard exposure. Even though our residual 

 toxicity tests suggest that intact sugar/flour PTS killed 

 at least 58-69% of alighting AMF during 6 weeks of 

 orchard deployment, the fact that more than a third of 

 such spheres were not substantially intact by the end 

 of 6 weeks probably accounts for the lesser degree of 

 AMF control provided by sugar/flour PTS. 



In 2000, 20-31% of sugar/wax discs atop wooden 

 PTS experienced 20% or more damage by vertebrates 



after 6 weeks of field exposure. In 200 1 , only 0- 1 1 % 

 of our new-version discs (protected by embedded wire) 

 experienced 20% or more damage by vertebrates after 

 a similar amount of field exposure, and all of the 

 observed damage was caused by raccoons in a single 

 orchard. No damage occurred from rodents. The level 

 of kill of alighting AMF by wooden PTS (37-39%) 

 after 6 weeks of sugar/wax disc exposure, coupled with 

 an average of 14% of survivors that were unable to fly, 

 gave rise to 51-53% incapacitated AMF that alighted 

 on wooden PTS. This level was less than the kill 

 atlorded by intact sugar/flour PTS (58-69%), but 

 apparently was sufficiently great to have provided 

 excellent protection of fruit against injury by AMF. 



For the future, we plan to focus on optimizing the 

 size of sugar/wax discs atop wooden PTS so that a 

 single disc might provide a sufficient supply of sugar 

 to the sphere surface to last for the entire 12-week 

 season of AMF activity in commercial orchards. We 

 know from 2001 results reported here that the 4% a.i. 

 level of imidacloprid in latex paint on the surface of a 

 wooden PTS is sufficient to kill all alighting AMF, even 

 after 12 weeks of orchard exposure. We also know 

 from results reported here that little or no sugar is likely 

 to remain in sugar/wax discs atop wooden PTS after 

 about 6 inches of rainfall. Our challenge thus lies not 

 in preserving the residual activity of insecticide, but in 

 ensuring a residue of sugar on wooden PTS. 



A ckn o wledgem en ts 



We are very grateful to the six growers who allowed 

 us to deploy traps in their orchards: Bill Broderick, 

 Dave Chandler, Aaron Clark, Wayne Rice, Dave 

 Shearer, and Mo Tougas. This project was supported 

 by state and federal IPM funds and grants from the 

 USDA CSREES Pest Management Alternatives 

 Program and Crops at Risk Program. 



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34 



Fruit Notes, Volume 66, 2001 



