Comparison of Avaunt versus Guthion 

 in Every-row versus Perimeter-row 

 Sprays Against Key Apple Insect Pests: 

 2002 Results and Project Summary 



Ronald Prokopy, Matthew Harp, Andrew Hamilton, Bradley Chandler, and 



Isabel Jacome 



Department of Entomology, University of Massachusetts 



In the 2001 issue oi Fruit Notes, we presented 

 results from the first year of a planned two-year study 

 comparing the effects of Avaunt versus Guthion in 

 every-row versus perimeter-row sprays against plum 

 curculio (PC), apple maggot (AM), summer leafrollers 

 (LR) and internal Lepidoptera (a combination of 

 codling moth, oriental fruit moth and lesser 

 appleworm). Avaunt is a recently-labelled oxadiazine 

 insecticide for use against these and other orchard pests. 

 Guthion has been our standard organophosphorous 

 material for general-purpose insect control for several 

 decades, but its status for use in orchards beyond 2005 

 is uncertain. Conceivably, Avaunt might be an effective 

 substitute for Guthion against key orchard insect pests. 



Avaunt and most other recently labelled 

 insecticides are substantially more expensive than 

 Guthion and other older insecticides. If the amount of 

 Avaunt needed to achieve effective pest control could 

 be reduced through modification of pattern of spray 

 application (such as limiting application to only 

 peripheral-row trees), then considerable cost savings 

 could be achieved without sacrifice of fruit quality 



Here, we present results of our second and final 

 year of research comparing effects of Avaunt versus 

 Guthion in every-row versus perimeter-row sprays 

 against PC, AM, LR, and internal Lepidoptera. We also 

 present combined data from our two years of research 

 on this subject. 



Materials & Methods 



In April of 2001, four plots were established in 

 each of six commercial apple orchards in 



Massachussetts (24 plots in all). Rootstocks and 

 cultivars varied among orchards, but all trees in a given 

 orchard were on the same rootstock (either M.7, M.26, 

 or M.9) and of the same cultivar (either Mcintosh, 

 Empire, Cortland, Gala, or Delicious). Each plot was 

 about 40 X 40 yards in size and consisted of seven rows 

 of apple trees. The perimeter row bordered woods, 

 hedgerow, or open field and was subjected to pressure 

 ft-om immigrating PCs and AM. In 2002, one of the six 

 orchards was so heavily damaged by firost that it could 

 not be used in our 2002 research. 



In 2002, as in 2001, growers themselves sprayed 

 all rows of all plots with azinphosmethyl or phosmet 

 through petal fall. Thereafter, all sprays were applied 

 by Andrew Hamilton using our own tractor-mounted 

 mist blower. Plots in each orchard received four sprays 

 after the petal fall spray: 10 days and again in 20 days 

 after petal fall against PC, and on July 1 9-2 1 and again 

 on August 9-11 against AM. Spray was delivered at 

 the equivalent of 1 50 gallons of water per acre. Guthion 

 (50 WP) was applied at the rate of 30 ounces of 

 formulated material per acre against PC and 24 ounces 

 of formulated material per acre against AM. Avaunt 

 (30% WG) was applied at the rate of 6 ounces of 

 formulated material per acre against both PC and AM. 

 After the petal-fall spray, plots designated as "all row" 

 plots received insecticide applied to both sides of trees 

 on all seven rows, whereas plots designated as 

 "perimeter-row" plots received insecticide sprays 

 applied to both sides of trees of the perimeter (=first) 

 and second rows but no insecticide applied to trees of 

 the third through seventh rows (Figure 1). After the 

 petal-fall spray, Andrew Hamilton applied 



Fruit Notes, Volume 68, Winter, 2003 



