Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/5/2009
Publication Date: 4/7/2010
Citation: Yee, W.L. 2010. Oviposition in Sweet Cherry by Reproductively Mature Western Cherry Fruit Fly (Tephritidae:Diptera) Fed Spinosad and Neonicotinoid Insecticide Baits. Journal of Economic Entomology. 103(2):379-385.
Interpretive Summary: Cherry fruit fly is a serious quarantine pest of commercial cherries in the Pacific Northwest. The fly is currently controlled using insecticides, but insecticides do not always protect cherries against attack by the fly. Mature flies that move into orchards from infested trees outside of orchards can lay eggs into fruit even when insecticides are applied. Personnel at the Yakima Agricultural Research Laboratory in Wapato, WA, are determining the effects of various insecticides in sugar and protein baits on preventing egg laying by these flies. We found that spinosad + thiamethoxam (Entrust + Actara) when ingested by flies prevented egg laying and was more effective than GF-120, the product commonly used by growers. This result is important because it indicates spinosad + thiamethoxam can play a role in protecting cherries from fly attack and that it can especially be important where infested trees are near managed orchards.
Technical Abstract: Western cherry fruit fly, Rhagoletis indifferens Curran, is a major pest of cherry, Prunus avium (L.) L., in the Pacific Northwest of the U.S. Spinosad bait is applied weekly to kill flies before they develop eggs, but its effects on oviposition by flies that are reproductively mature are unknown. The main objective of this study was to identify insecticides and insecticide mixes in spinosad or sucrose baits that can prevent oviposition after being ingested by reproductively mature R. indifferens. First, flies were fed fresh bait solutions. Flies fed spinosad bait all died within 1 d, but 20.0% oviposited. All flies fed acetamiprid + sucrose recovered from paralysis within 1 d and 71.7% oviposited after 1 wk. Most flies fed spinosad bait + acetamiprid died within 1 d, but 7.4% oviposited. All flies fed spinosad bait + thiamethoxam died within 1 d and none oviposited. Most flies fed thiamethoxam + sucrose died within 1 d, but 1.7% oviposited. However, all flies fed spinosad + thiamethoxam + sucrose died within 1 d and none oviposited. Almost all flies fed spinosad + sucrose died within 1 d, but 11.1% oviposited. Next, flies were fed 2-d old dried baits. Dried spinosad + thiamethoxam + sucrose and thiamethoxam + sucrose both prevented oviposition. On the basis of absolute numbers of eggs laid by flies fed treatments in solution and in dry form, spinosad + thiamethoxam + sucrose may be the most effective of the seven baits tested for preventing oviposition by reproductively mature R. indifferens.