Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 12, 2010
Publication Date: February 1, 2011
Citation: Yee, W.L. 2011. Mortality and Oviposition in Western Cherry Fruit Fly (Diptera:Tephritidae) Exposed for Different Periods to Insecticide Baits in the Presence and Absence of Food. Journal of Economic Entomology. 104:194-204.. Interpretive Summary: Western cherry fruit fly is an important pest of cherries in the Pacific Northwest. GF-120 bait sprays are effective against young flies that have not developed eggs, but they are less effective against older flies that have developed eggs and that can move into orchards from outside sources. Personnel at the USDA-ARS Yakima Agricultural Research Laboratory in Wapato, WA, are determining if there are more effective bait sprays than GF-120 against older flies. We found that a neonicotinoid, Actara, mixed with sugar bait was more effective at killing older flies and preventing their egg laying than GF-120. This result is important because it provides cherry growers an alternative product to protect their crop when there are older flies moving into their orchards from outside sources.
Technical Abstract: Spinosad bait is used to control western cherry fruit fly, Rhagoletis indifferens Curran, in the Pacific Northwest of the United States, by killing flies before they can oviposit. However, effects of different insecticide baits on management of reproductively mature flies are largely unknown. The objectives in this study were to determine mortality and oviposition of reproductively mature R. indifferens exposed to different insecticide baits for varying periods in the presence and absence of food. Spinosad bait and neonicotinoid insecticides mixed in sucrose or Nu-Lure + sucrose bait were compared. When flies were exposed to insecticide baits and then offered cherries for oviposition or when they were exposed to insecticide bait and cherries simultaneously, thiamethoxam bait and imidacloprid bait caused higher mortality and lower oviposition than spinosad bait and acetamiprid bait. Exposures to thiamethoxam bait and imidacloprid bait for 6 and 24 h were similarly effective, but 6-h exposures to spinosad bait and acetamiprid bait were less effective than 24-h exposures. There was few differences between sucrose and Nu-Lure + sucrose baits. When food was present, thiamethoxam bait and imidacloprid bait caused greater mortality and lower oviposition than spinosad bait and acetamiprid bait, but when it was absent, there were fewer differences among the insecticide baits. Because of their ability to kill flies more quickly regardless of food presence, an application of thiamethoxam or imidacloprid in either sucrose or Nu-Lure bait may reduce infestations in cherries more than that of spinosad bait when mature R. indifferens are present in orchards.