On the other hand, a substantial proportion of 

 those curcuhos observed to crawl off the cloth 

 (about 20%) did so at temperatures of 67°F or 

 less, and there was no correlation between tem- 

 perature and proportion of total observed 

 curculios that crawled off. 



Conclusions 



The more robust data reported here confirm 

 and extend the preliminary data reported in the 

 1997 Winter issue of Fruit Notes. Combined 

 data indicate that when the air temperature is 

 67°F or less beneath the canopy of a host tree, 

 the plum curculio adults that have dropped from 

 the tree canopy (as they normally do on a fre- 

 quent, even daily, basis) are reluctant or unable 

 to fly but are able to reenter the tree canopy by 

 crawling. Crawling is almost exclusively toward 

 the tree trunk, or if a black pyramid trap is 

 adjacent to the tree trunk, then toward such a 

 trap, which is thought to be a visual mimic of a 

 tree trunk. At temperatures of 68°F or greater, 

 curculios exhibit an increasing propensity to 



reenter the tree canopy by flight. Most flights 

 are into the tree canopy. Only a small propor- 

 tion (15-17% according to our findings here) is 

 toward the tree trunk or a black pyramid trap 

 next to the tree trunk. Hence, at temperatures 

 of 68°F or greater, there is only a small chance 

 of capturing a tree-reentering curculio using a 

 black pyramid trap. Other data that we col- 

 lected in 1997 show that curculio damage to tree 

 fruit increases with increasing temperature. It 

 is therefore doubtful that any prospective 

 unbaited curculio traps placed in association 

 with the tree trunk will be able to monitor 

 curculio entry into or abundance in the tree 

 canopj/^ in a way that reflects accurately the 

 probability of curculio damage to fruit. 



Acknowledgments 



This work was supported by a grant from the 

 USDA Northeast Regional IPM Competitive 

 Grants Program and the New England Tree 

 Fruit Research Committee. 



*X* *X* *X^ *^ *X* 



#Y* *Y* *T* *T* *T* 



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



13 



