Are Adult Plum Curculios Capable of 

 Overwintering Within Apple Orchards? 



Jaime Piiiero, Everardo Bigurra, Isabel Jacome, Guadalupe Trujillo, and 



Ronald Prokopy 



Department of Entomology, University of Massachusetts 



In the preceding article on the effectiveness of 

 peripheral-row vs. all-row sprays against plum curculio 

 (PC), results indicated that spraying only peripheral rows 

 of apple trees beginning at petal fall was insufficient 

 for adequate orchard-wide control of PC. Two reasons, 

 alone or in combination, were put forward to explain 

 this insufficiency: ( 1 ) enough PCs overwintered within 

 the intenor of commercial orchards (inside of peripheral 

 rows) to cause excessive fruit injury on interior trees 

 that were left untreated against PC, and (2) excessive 



fruit injury on interior trees was caused by PCs that 

 overwintered in woods and hedgerows and penetrated 

 into interior rows before a petal fall spray was applied 

 to peripheral rows. 



Here, we report results of an experiment conducted 

 in 2003 aimed at addressing the first explanation. We 

 asked whether PCs were able to overwinter 

 successfully inside of two blocks of a commercial 

 orchard in Massachusetts that differed primarily with 

 respect to type of management (weed control). 



PLOT A (managed) 



PLOT B (unmanaged) 



Figure 1. Representation of trap deployment in Plot A (subjected to weed management) and Plot B (not 

 subjected to weed management) to determine distribution of PC overwintering in 2003. For each plot, 60 

 emergence traps were arranged in 12 transects (only one transect is shown). Each transect consisted of five 

 emergence traps located at different sites (denoted as 1-5) along each transect. 



Fruit Notes, Volume 69, Winter, 2004 



