ers and white apple leafhoppers have been on the rise in 

 IPM orchards over the past 5 years (partly due to develop- 

 ment of resistance to materials previously effective). 

 Having substantially achieved our goals, we initiated the 

 second stage of the apple IPM program in 1987. 



Second-stage IPM employs behavioral, ecologi- 

 cal, and biological approaches to pest management as 

 substitutes for most pesticide treatments. The major goal 

 of the program is to eliminate use of insecticides and 

 miticides after the last curculio spray. This elimination 

 allows important predators and parasites of key foliage- 

 feeding pests (mites, aphids, leafminers, and leafhoppers) 

 to build up to numberssufficient to provide control of these 

 pests. To facilitate this goal, we emphasize the use, during 

 April and May, of those pesticides least likely to be harmful 

 to beneficial predators and parasites. 



In the summer of 1987, 18 commercial orchards 

 participated in the second-stage IPM program comprised 

 of the following 4 elements: 



(1) application of oil or other needed selective pesticides 



(1) during April and May to control European red mite, 

 San Jose scale, tarnished plant bug, European apple sawfly, 

 plum curculio, green fruitworms, and early-season leaf- 

 rollers; 



(2) no use of any insecticide or miticide following the last 

 plum curculio spray in May to permit buildup of beneficial 

 predators and parasites in a pesticide-free habitat (except 

 for fungicide use against diseases); 



(3) removal of abandoned apple, pear, hawthorn, and 

 quince trees within 100 yards or more of the orchard 

 perimeter to greatly reduce or preclude immigration of key 

 mid- and late-season lepidopteran pests (codling moth and 

 summer leafroUers) attacking apple fruit; and 



(4) intercepting apple maggot Hies (a key summer pest 

 attacking the fruit) before the great majority of flies can 

 penetrate the orchard interior, either by ringing the or- 

 chard perimeter with odor/visual maggot Oy traps (sticky 

 red sphercsbaited with synthetic apple odor) or by spraying 

 perimeter-row apple trees periodically to kill entering files. 



Of the 18 blocks (2 to 4 acres each) there were 6 

 in which odor/visual traps for apple maggot files were 

 placed every 10 yards in the woods surrounding each block, 

 6 in which odor/visual traps were placed every 10 yards in 

 perimeter apple trees, and 6 in which perimeter apple trees 

 were sprayed every 3 weeks during June, July, and August. 

 We compared results in these blocks with a comparable- 

 size nearby block in each orchard sprayed by growers in 



normal fashion during June, July, and August. 



Table 1 shows that on average 1,062 maggot files 

 per orchard were intercepted in test blocks where traps 

 were put in the woods, compared with 2,054 where the traps 

 were placed in perimeter apple trees. One hundred 

 percent more files were caught on nonbaitcd monitoring 

 traps placed in interior apple trees in woods-trapped test 

 blocks than in grower control blocks, suggesting that twice 

 as many files were active in the interior of these test blocks 

 than in the adjacent control blocks. About 46% more were 

 caught on monitoring traps inside the apple-tree-trapped 

 test blocks and 65% more in the border-row-sprayed test 

 blocks than in the adjacent control blocks. Although none 

 of the 3 approaches to intercepting maggot files before fiy 

 penetration into the block interior was completely effec- 

 tive, the latter 2 types gave promising results. 



Table 1. Apple maggot fiy captures per block. 



Type of block 



Interception Monitoring 

 traps* traps** 



AMP traps in woods 1,062 



Grower control 



AMF traps in orchard 2,054 

 Grower control 



Border row sprays 

 Grower control 



352 

 176 



123 

 84 



104 

 63 



*Odor-baitcd traps at orchard perimeter. 

 **Nonbaitcd traps on interior apple trees. 



Table 2 shows the percent fruit damaged by each 

 type of fruit-injuring pest. For all 3 test block types, 

 combined injury by early season pests (plant bugs, sawfiies, 

 curculios, and fruitworms) was greater in the test blocks 

 than in the grower control blocks. These pests would have 

 been controlled by sprays applied during April and May 

 (prior to the start of the program). Hence, it appears that 

 pest pressure in and around the average test block was 

 greater than that in and around the average control block 

 (so the cards were partly stacked against us). Maggot files 

 caused about 4 times as much damage in woods-trapped 

 test blocks as in control blocks (9.3 vs. 2.3%), about 3 times 

 more damage in apple-tree-trapped test blocks as in con- 

 trol blocks (1.4 vs. 0.5%), and about the same amount of 



