Acta Entomologica Sinica (2005) 48, 531-536

Gang Wu and Miyata Tadashi (2005)
Seasonal dynamics of resistance to six insecticides in the field populations of parasitoid Diaeretiella rapae (M'Intosh) (Hymenoptera: Aphidiidae)
Acta Entomologica Sinica 48 (4), 531-536
Abstract: The resistance to six insecticides in the field populations of Diaeretiella rapae (Hymenoptera: Aphidiidae),a parasitoid of vegetable aphid collected in Jianxin, Fuzhou City, and Shangjie, Minhou County, Fujian, China, was studied using dry residual film method. The susceptibility to insecticides in a field population of D. rapae increased significantly after being reared in the field insectarium under insecticide free conditions. Compared to susceptible F₂₁ reared in the insectarium, the resistance ratios were 11.8-31.2 for methamidophos, 9.3-14.7 for fipronil, 9.3-35.7 for avermectin, 7.0-16.6 for fenvalerate and 13.3-30.1 for imidacloprid, respectively in Shangjie populations during June 8, 2002 to November 18, 2004; and 7.5-34.9 for methamidophos, 4.0-14.3 for fipronil, 9.2-38.6 for avermectin, 7.8-18.9 for fenvalerate and 12.1-24.2 for imidacloprid, respectively in Shangjie populations during June 5, 2003 to December 17, 2004. RR in field populations of D. rapae was the highest in May, early June and November, lower in December, and the lowest in the end of June. In particular, RR decreased markedly in about 20 days from the beginning to the end in June. The results indicated that the resistance levels to methamidosphos, fipronil, avermectin, fenvalerate, cypermethrin and imidacloprid in D. rapae were not stable after relaxation from the selection pressure of insecticide, and that there existed significantly seasonal variations of resistance levels to the six insecticides in D. rapae.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Database assignments for author(s): Gang Wu

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
resistance to pesticides

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Lipaphis erysimi		China (south)
Diaeretiella rapae (parasitoid)	Lipaphis erysimi		China (south)