Submitted to: Journal of Agricultural and Urban Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/19/2007
Publication Date: 12/15/2007
Citation: Yee, W.L. 2007. Gf-120, nulure, and mazoferm effects on feeding responses and infestations of western cherry fruit fly (Diptera: Tephritidae). Journal of Agricultural and Urban Entomology 23(3):125-140. Interpretive Summary: Cherry fruit fly is a serious quarantine pest of commercial cherries in the Pacific Northwest. Knowledge about the effects of bait and insecticide sprays is needed to manage the fly. Personnel at the Yakima Agricultural Research Laboratory in Wapato, WA, are determining the effects of three protein bait sprays on feeding responses and on control of the fly. We found that flies fed on all three baits mixed with insecticides, but that the flies were no more attracted to them than to water. When the baits were sprayed on whole trees, infestations of cherries with larvae were greatly reduced but not eliminated. The results of this study are important in that they indicate the bait sprays tested are not attractive to flies and that they work because flies find and feed on them through normal foraging on leaves and then die. This mechanism is apparently sufficient to kill most flies, but because infestations need to be eliminated, the attractiveness of baits may need to be increased to optimize effectiveness.
Technical Abstract: A study was conducted to determine feeding responses of western cherry fruit fly, Rhagoletis indifferens Curran, to 40% (vol/vol) GF-120, Nulure, and Mazoferm bait and to the insecticide spinosad only in 2005 and 2006 in Washington State. When water or baits were sprayed on branches or were placed as single drops on leaves 1-2 cm from flies, the numbers of flies subsequently seen near or feeding on the water and baits were similar, although flies fed longer on GF-120 than on other baits. From 4.8-23.1% of flies that contacted water or baits did not respond by feeding or maintaining contact with drops. Female and male responded similarly. Later in the season (31 May to 9 June), responses to all baits were greater than early in the season (19 to 30 May). When whole, single trees with higher fly pressure than found in most commercial orchards were sprayed with treatments, Nulure and Mazoferm significantly reduced larval infestations in fruit compared with the control in one test, but they, GF-120, and spinosad only did not significantly reduce larval infestations compared with controls in two other tests. Results suggest the baits tested were not attractive to R. indifferens compared with water and that most flies find them through chance encounters, which may partially explain the lack of consistent larval control using baits. GF-120 did not retain flies longer once they began to feed. Whether baits can be made more attractive over long periods and whether more attractive baits result in further reductions or consistent elimination of infestations needs to be examined.