* Means within rows not followed by the same letter are significantly different at 

 odds of 19:1. 



responders that we tested with male respond- 

 ers in experiment 1. In arena one, female re- 

 sponders were attracted to males plus plums 

 in significantly greater numbers than to males 

 alone or the control bag, with intermediate at- 

 traction to plums alone. In arena two, signifi- 

 cantly more females were attracted to plums 

 alone than to controls, with intermediate at- 

 traction to females plus plums. 



In experiment 4 (Table 4), we repeated the 

 same treatments with female responders that 

 we had tested with male responders in experi- 

 ment 2. In arena one, females responded in 

 nearly equal numbers to punctured plums and 

 plums that had not been punctured. In arena 

 two, numerically more females were attracted 

 to males plus plums compared to females plus 

 plums or to control. 



Conclusions 



Both sexes were attracted to odors emitted by 

 freshly picked wild plums. Perhaps the most 

 important result from these experiments is an 

 indication of the existence of a female-produced 

 sex pheromone, as evidenced by the strong at- 

 traction of male PCs to the treatment that in- 

 cluded females plus wild plums. Further, this 

 putative female-produced pheromone may have 

 been synergized or enhanced in attractivity to 

 males by the presence of wild plum odor. Al- 

 though we cannot rule out the possibility of 

 sounds made by PCs as influencing these re- 

 sults, we could smell a unique odor in arenas 

 that included treatments containing females 

 plus plums. We plan to use this bioassay sys- 

 tem extensively in 1998 to confirm these pre- 

 liminary findings and in tests aimed at identi- 

 fying the chemical nature of these attractive 

 compounds. 



We conclude that the Plexiglas arena bioas- 

 say system is an effective way to test PC at- 

 traction to host fruit odors as well as odors 

 emitted by other PCs at distances of approxi- 

 mately 16 inches under still-air conditions. 



Acknowledgments 



This work was supported by Hatch funds 

 and by the New England Tree Fruit Growers 

 Research Committee. 



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Fruit Notes, Volume 63 (Number 1), Winter, 1998 



