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cherry fly egg layings in fruit in laboratory cages. They s\\fished. 

 this fruit in water, and sprayed 10 cherry trees in nature with 2 

 applications of the pheromone-water solution. The results were ex- 

 tremely encouraging: only 61 of the pheromone-sprayed cherries had 

 any cherry maggot eggs or larvae, compared with 100% maggot infesta- 

 tions of adjacent unsprayed cherries. 



In the past 2 months, Reggie Webster and I have discovered that 

 the fruit marking pheromone of the apple maggot acts net only as 

 an egglaying deterrent to maggot flies but acts also as a chemical 

 signal to Opius lectus , a parasite of the maggot eggs. The phero- 

 mone arrests the parasite females, and elicits a strong degree of 

 searching behavior for maggot eggs. Parasites encountering fruits 

 sprayed with marking pheromone are therefore likely to remain in 

 the area of the pheromone-sprayed tree for a longer time and effec- 

 tively search out any maggot eggs that might be in the fruit. 



The task facing us now is the chemical identification and syn- 

 thesis of the marking pheromone. This will require the expertise 

 and equipment of an accomplished pheromone chemist, which are few 

 in number. We hope in the near future to interest one of them in 

 tackling this challenging pheromone. If some day the pheromone can 

 in fact be obtained at reasonable cost, then the pheromone, com- 

 bined with an effective spreader-sticker, could be sprayed onto our 

 apple trees to prevent maggot fly egglaying. The deterred females, 

 which we know move about frequently, might then be captured out by 

 baited yellow rectangles and/or baited red spheres hung in specific 

 trap trees. Native or released Opius lectus female parasites would 

 be retained in the area by the presence of the pheromone. Thereby, 

 an integrated approach to apple maggot management, combining deter- 

 rents, attractants, and parasites, could hopefully be achieved. 



