MONITORING APPLE MAGGOT FLIES, 

 SAWFLIES, AND PLANT BUGS WITH VISUAL TRAPS 



Ronald J. Prokopy 

 Department of Entomology 



Introduction 



With the advent o£ integrated pest management programs in 

 commercial apple orchards inMassachusetts and other apple-growing 

 regions of the United States, there is increased emphasis on the 

 ability of growers, orchard scouts, and extension agents to accur- 

 ately monitor population levels of injurious apple insects and 

 mites . 



Certain pests, such as aphids, spider mites, leafhoppers, 

 leafminers, and scale insects attack principally or exclusively 

 the vegetative parts of the tree and can be tolerated in small 

 or even moderate numbers without economic injury. Their popu- 

 lation levels can be monitored with reasonable accuracy by direct 

 visual examination of foliage or branches. 



Other pests, such as green fruitworms and oblique-banded, 

 red-banded, and fruit-tree leafrollers feed, as larvae, from 

 the exterior of the fruit. While even a few larvae may cause 

 economic injury, larval populations and the readily discernible 

 injuries they cause, can be rather accurately monitored by direct 

 visual examination of fruit. 



Still other pests, such as tarnished plant bug, European 

 apple sawfly, plum curculio, apple maggot, and codling moth, 

 feed as adults or larvae on developing buds or fruit. They 

 can not be tolerated in appreciable or even small numbers with- 

 out economic injury. Except for plum curculio, their feeding 

 and egglaying activities are rather difficult and tedious to 

 accurately detect by direct observation. Populations of these 

 pests are best monitored in the adult stage. The monitoring 

 method must be sensitive, so that detection of very low popu- 

 lation densities is possible, and pesticide application, if nec- 

 essary, can be made before the occurrence of economically un- 

 acceptable feeding injury or egglaying. 



In the 8 commercial apple orchards in our 1978 integrated 

 pest management (IPM) program in Massachusetts, it was the lat- 

 ter 5 pests which accounted for nearly all of the insect injury 

 on the 16,000 apples examined at harvest: 1.601 by plant bug, 

 0.68°^ by sawfly, 0.17% by plum curculio, 0.131 by apple maggot, 

 and 0.01% by codling moth, with all remaining insect injury to 

 the fruit totalling 0.051 (see Fruit Notes 44(1) for further in- 

 information on the 1978 results of the apple IPM program in Massa- 

 chusetts). This same sort of insect injury pattern is probably 

 characteristic of several other eastern states as well. 



