• Korean journal of applied entomology
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• v.52 no.4
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• pp.379-386
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• 2013

Aphidius colemani and Orius laevigatus aree natural enemies of the control cotton aphid and western flower thrips, which are the major pests of cucumber plants. We evaluated the low toxicity of 47 fungicides against A. colemani and O. laevigatus, and we investigated the simultaneous effect of the natural enemies with fungicide of low toxicity on the pests. The toxicity of DBEDC, hexaconazole, pyraclostrobin, tribasic copper sulfate, triflumizole, chlorothalonil, flusilazole, folpet, carbendazim+diethofencarb, cymoxanil+fenamidone and trifloxystrobin to A. colemani mummies was more than 50% and to O. laevigatus was low toxic. Among the fungicides with low toxicity, azoxystrobin 20% WP was selected because it could be used simultaneously with A. colemani and O. laevigatus and as a fungicide to control powdery mildew and downy mildew. In 2011, the densities of western flower thrips and cotton aphid increased rapidly in early-May in Gongju and Cheonan, Chungnam Province. When azoxystrobin was used at an interval of 10 days in spring, A. colemani and O. laevigatus were released at an interval of 7 days at the early occurrence of the pests. The natural enemies decreased the densities of the pests; the maximum number of A. colemani mummies was 18 per lower leaf, and the maximum number of O. laevigatus was 0.5 per flower. Azoxystrobin did not influence the densities of A. colemani and O. laevigatus. The results show that the selected fungicides can be used with A. colemani and O. laevigatus for the intergrated pest management of cotton aphid and western flower thrips in cucumber polyvinyl house cultivation.