D Flies caged immediately following spray 



■ Flies caged 24 hours after spray 



■ Flies caged on unsprayed leaves 



Oviposition puncture 



Eggs laid 



Egg load 



Figure 2. Mean number of oviposition punctures, eggs laid, and egg load per female among 

 apple maggot Hies that survived exposure to Provado during 7 days in field cages 



from pupae collected from unsprayed apple drops. Five 

 apple trees were selected from an abandoned orchard 

 near Amherst, Massachusetts. Branches of four trees 

 were sprayed to runoff at a dose of 0.03% a.i. of 

 Provado, the rate labeled for controlling sucking in- 

 sects in apple orchards. The fifth tree was not sprayed 

 and used as a control. For each tree, four branches 

 were selected for caging flies, using 30x50-cm cloth 

 screen net. Two fruit were allowed to remain on each 

 branch. Four leaves on each branch received an aque- 

 ous slurry of a mixture of 8% sugar and 10% bird drop- 

 pings to serve as a food supply for flies. Two cages 

 per tree received 20 flies (10 males and 10 females) 

 immediately following spray application. The other 

 two cages received like numbers of flies 24 hours later. 

 Mortality counts were made daily for 7 days. To 

 determine possible effects on fly reproduction, apples 

 and surviving flies from each cage were brought back 

 to the laboratory on the 7"' day. Apples were exam- 

 ined to detemiine the effects of Provado on fly ovipo- 

 sition behavior by counting the number of oviposition 

 punctures and number of eggs laid. Female flies were 

 dissected to determine effects of Provado on egg load 

 by counting the number of mature eggs in fly ovaries. 



Results 



Our results indicate that application of Provado to 

 apple tree foliage and fruit neither effectively reduced 

 fly survival (Figure 1 ) or fly reproductive ability (Fig- 



ure 2). Less than 20% of flies caged immediately after 

 spray application were killed over the 7-day test pe- 

 riod, too low to provide effective control. Mortality 

 was even lower (8%) for flies released into cages 24 

 hours after spraying. This was essentially no greater 

 than the 5% mortality of flies in the control cages. The 

 results suggest a rapid decline of Provado activity on 

 leaf and fruit surfaces after application. 



Figure 2 shows that fly oviposition behavior was 

 only slightly reduced for flies exposed to sprayed com- 

 pared with unsprayed leaves and fniit. Groups of flies 

 exposed to foliage and fruit immediately after spray- 

 ing with Provado made an average of 16 ovipositional 

 punctures and laid an average of 14 eggs over 7 days, 

 compared with 1 9 ovipositional punctures and 1 7 eggs 

 laid by tlies expo.sed to foliage and fruit 24 hours after 

 spraying, and 21 ovipositional punctures and 19 eggs 

 laid by control flies. The egg load per female remained 

 at essentially the same level for all the treatments. 

 These results suggest that Provado applied to apple 

 foliage and fruit had minimal effects of fly oviposi- 

 tion. 



Conclusions 



Even though Provado has proven excellent in pro- 

 viding season-long control of .sucking in.sect pests on 

 apple trees, and even though our laboratory tests 

 showed high toxicity of Provado to apple maggot flies, 

 the results generated here indicate that Provado ap- 



Fruit Notes, Volume 63 (Number 2), Spring, 1998 



