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the use of CA in today's horticultural industry. Proceedings of 

 this Conference should be of interest and value to everyone in- 

 volved in CA storage. We will inform you in Fruit Notes how to ob- 

 tain copies when they are published. 



*************** 



MONITORING TRAPS FOR BLUEBERRY MAGGOT FLIES 



Ronald J. Prokopy and William M. Coli 

 Department of Entomology 



The blueberry maggot, Rhagoletis mendax, is generally consid- 

 ered the most important insect pest of commercially grown highbush 

 blueberries in the eastern and mid-western United States. The 

 adults look identical to apple maggot adults, but are a different 

 species. They emerge from overwintering cocoons about the time 

 earliest-ripening berries are turning reddish blue. They feed for 

 about 10 days-principally on insect honeydew on foliage, mate, and 

 then commence laying eggs into the berries. The eggs hatch in 

 about 4 days, and the larvae (maggots) feed for about 2 weeks on 

 the flesh of the berry, causing it to rot. Infested berries may 

 look in fine condition on the outside but be soft and mushy inside. 

 When no measures are taken to prevent injury, 501 or more of ripe 

 berries may be maggot infested. 



The standard method of controlling the blueberry maggot is 

 application of 3-5 insecticide treatments against the adults. At 

 present, the treatment schedule followed by most growers is a type 

 designed to prevent any possible maggot injury, irrespective of 

 whether or not maggot flies are actually present. If there were 

 a method available for accurately assessing fly abundance in the 

 plantation and eventually relating fly density to level of larval 

 infestation, then the decision as to whether or not insecticide 

 should be applied could be made on a firm cost-benefit basis. Un- 

 necessary and uneconomical sprays could be eliminated, resulting 

 in (a) monetary savings to the grower, (b) less pesticide residue 

 on and in the fruit and in the environment, (c) less selective 

 pressure for rapid development of maggot fly resistance to insecti- 

 cides, and (d) greater opportunity for natural enemy buildup. Un- 

 til now, no effective method for assessing blueberry maggot fly 

 abundance has been available. 



In 1976 and 1977, we studied the reactions of blueberry mag- 

 got flies to visual and combined visual-odor stimuli. When we 

 tested their responses to 6 x 8 inch painted cardboard rectangles 



Graduate Student in Department of Plant and Soil Sciences 



