Commercial-orchard Trial of Unbaited 

 Traps for Monitoring Plum Curculio: 

 1998 Results 



Starker Wright, Stephen Lavallee, and Ronald Prokopy 

 Department of Entomology, University of Massachusetts 



For the past 3 years, we have performed field and 

 laboratory studies aimed at developing an effective trap 

 for monitoring plum curculio (PC) in commercial or- 

 chards. Our goal in trap development is to establish a 

 system whereby growers can predict the need for and 

 timing of sprays. 



In 1996, we evaluated unbaited black pyramid traps 

 in small orchard blocks in Belchertown, MA, Conway, 



MA, and South Deerfield, MA. Our principal finding 

 in this study was that unbaited pyramid traps are inef- 

 fective in warm weather. When the temperature rises 

 above 20"C (when most PC injury occurs), PCs enter 

 trees largely by flying directly into the tree canopy, 

 bypassing the tree trunks and trunk-associated pyra- 

 mid traps. 



In 1 997, black pyramid traps were evaluated at three 



(a) 



(b) 



48 inches 



A 



12 inches 



<- 



^ 



-> 



24 inches 



3 inches 



Figure 1 . Trap designs used in the 1 998 field (rial: (a) unbaited trunk-mimicking pyramid trap, placed adjacent to 

 the tree trunk and (b) unbaited tvvig-mimicking cylinder trap, positioned wiihiii ihe tree canopy and kept m a 

 vertical position by a clipped upright twig. 



Fruit Notes, Volume 63 (Number 3), Summer, 1998 



