Chinese Journal of Entomology (2000) 20, 109-118

Ju-Chun Hsu and Hai-Tung Feng (2000)
Insecticide susceptibility of the oriental fruit fly (Bactrocera dorsalis (Hendel)) (Diptera: Tephritidae) in Taiwan
Chinese Journal of Entomology 20 (2), 109-118
Abstract: Toxicity of fenitrothion, fenthion, malathiom, naled, and trichlorfon, to oriental fruit fly (Bactrocera dorsalis (Hendel)) adults was assayed in the laboratory. Chemicals were applied topically to mesonotum of 3- to 5-d-old adults. The LD50 data thus obtained from a laboratory strain when compared with past data revealed that except for trichlorfon, the LD50 for other chemicals were higher by, 1.9 to 4.3 folds. Field strains of fruit flies were collected in Taiwan 1996, and using the past LD90 as the diagnostic dose, and insecticide resistance was assessed. The same test was performed with laboratory strain of the insect. At LD90, only trichlorfon was beyond the upper limits of the confidence intervals, all others were under 50% mortality. In insecticide toxicity assays conducted in 1997 and 1998, on flies collected from around Taiwan, two additional chemicals, formothhion and methomyl, were tested utilizing topical application method. The overall insecticide toxicity in 1998 was some what higher than in 1997, but there was no significant difference between them. The overall insecticide toxicity was significantly higher to insects collected from Hsinbu and Qionglin than to those collected from other investigated locations. At the LD50, fenitrothion, malathion, and trichlorfon were the least toxic and have lost pest control effectiveness at the recommended concentration use in Taiwan. Fenthion and naled were most effective. Effective measures to reduce insecticide resistance selection are needed to sustain the utility of these chemicals in combating oriental fruit flies in Taiwan.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Database assignments for author(s): Ju-Chun Hsu, Hai-Tung Feng

Research topic(s) for pests/diseases/weeds:
control - general
pesticide resistance of pest

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Bactrocera dorsalis		Taiwan