Summer Fruit-injuring Pests: 

 Full Second-level IPM 



Odor-baited sticky red spheres were hung every 

 five yards on perimeter apple trees of each full 

 second-level experimental block to intercept immi- 

 grating AMF. These were baited with both butyl 

 hexanoate, a synthetic fruit odor deployed in poly- 

 ethylene vials, and ammonium acetate, a synthetic 

 food odor released through a Consep^'* membrane. 

 Traps were cleaned biweekly, based on data from 

 1992 suggesting a loss of capturing power with 

 increase of length of time between cleanings. 



Interception trap captures averaged 5023 in the 

 six full second-level blocks, as compared with 2430 in 

 1992 and 3562 in 1991, indicating that AMF pres- 

 sure was exceptionally high in 1993. Even so, 

 captures of AMF on four interior unbaited monitor- 

 ing traps (indicative of AMF penetration into the 

 block interior) were similar in full second-level 

 blocks and nearby first-level blocks (Table 3). AMF 



injury to fruit at harvest averaged slightly but not 

 significantly greater in second-level than first-level 

 blocks (0.7 vs. 0.3) (Table 3). The power of intercep- 

 tion traps for controlling AMF is illustrated in one 

 full second-level block of 10 acres where more than 

 21,000 AMF were captured on the traps but less than 

 1% of Mcintosh, Cortland, and Delicious apples were 

 injured by AMF. It should be noted, however, that 

 late-ripening cultivars (e.g., Delicious and Golden 

 Delicious) consistently have proven to be more sus- 

 ceptible to AMF injury than mid- or earlier-ripening 

 cultivars under full second-level practices. 



The problem of effective control of AMF in late- 

 ripening cultivars remains a challenging one for us. 

 In one block that suffered 8% AMF injury to 

 Cortlands in late September of 1992, we hung perim- 

 eter traps significantly higher in the tree in 1993 

 than in 1992 in an attempt to increase trap captures 

 of AMF before fruit injury occurred. We found only 

 1% AMF damage to the Cortlands at harvest this 

 year, though it should be noted that the fruit was 



Table 3. Season-long apple maggot fly (AMF) injury and trap captures in second- 

 level IPM blocks and first-level IPM blocks in 1993.* 



Means in each couplet in each column followed by a different letter are 

 significantly different at odds of 19:1. Two hundred fruit of each cultivar present 

 in both second-level and corresponding first-level blocks were sampled at harvest. 

 All blocks contained at least one of the following cultivars, and some contained 

 three of these: Mcintosh, Cortland, Delicious, Empire, Golden Delicious. 

 Average number of fruit sampled per block = 500. When sampling a cultivar, we 

 examined 10 fi-uit on each of 20 interior trees and 10 on each of 10 perimeter-row 

 trees (when cultivar present on a perimeter row). 



Data on AMF injury to fruit from one orchard have been excluded due to 

 excessively high late-season damage to several cultivars in both the second and 

 first-level blocks possibly caused by lack of AMF control methods by grower in 

 surrounding blocks. 



Fruh Notes, Winter, 1994 



