between tree branches was nearly rotten when found and did have larval exit 

 holes. Several bushels of fruit were picked up beneath these 3 trees on 

 July 15 and were placed over wire traps to obtain pupae. The average yield 

 was about 6 pupae per apple, revealing the high level of fruit infestation. 



Table 1. First appearance of exit holes of apple maggot larvae in Early Mcintosh 

 drops. 



NO. FRUIT IN WHICH A LARVAL EXIT HOLE FIRST Af REARED 



AT SUCCESSIVE INTERVALS (DAYS) AFTER FRUIT DROP PICKUP* 



Day of J^ 6^7 10-11 U-l'* 16-17 20-21 More Than 

 Drop pickup Days Days Days Days Days Days 21 Days 





 

 

 

 

 

 

 2 

 

 



TOTAL 



424 



22 



% FRUIT WITH 

 AN EXIT HOLE 



0.5 



0.2 3.3 17.0 37.3 35.4 



5.2 



1.2 



*Once an exit hole was detected in a fruit, that fruit was discarded. 



In the second test, carried out at the Horticultural Research Center at 

 Belchertown, we inserted 4 apple maggot eggs into each of 5 previously uni- 

 fested Mcintosh apples (a mid-season variety) during each of 4 weeks from 

 late July until late August. We placed a cloth bag over each fruit to catch 

 the fruit when it dropped. We looked at each cloth bag for drops every 3-4 

 days until all fruit had dropped (first drop was August 9> last drop was 

 October 4). Of the 80 fruit, not a single larval exit hole appeared at the 

 time of drop pickup nor even within the first week after drop pickup. Each 

 fruit did eventually produce mature larvae, however. 



In the final test, we placed cloth bags on September 10 over 1121 

 Crataegus mol 1 i s (hawthorn) fruit heavily infested with apple maggot larvae. 

 The fruit are a native host of this species. Every 3-4 days until the last 

 fruit had fallen, new drops were examined for larval exit holes. 



The results (Table 2) show that 203 fruit (18%) exhibited an exit hole 

 made by a larva sometime within the period between dropping and examination. 



