• Korean journal of applied entomology
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• v.48 no.2
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• pp.253-261
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• 2009

For the environment-friendly control of beet armyworm, Spodoptera exigua, in spring onion fields, we have examined an alternative application method. Twenty-five insecticides registered for spring onion were tested for control effect against the beet armyworm in the laboratory, then the best 9 chemical and a single biological insecticides were selected and compared with 2 new isolates of Bacillus thuringiensis in a polyvinyl house. After that, 4 chemical and 3 B. thuringiensis treatments were used in the field for the control of beet armyworm in the spring onion. Two application methods are used: one is triple treatments with the same chemical and the other is alternative application with different chemicals and B. thuringiensis for 7 days intervals. Indoxacarb WP - chlorfluazuron EC - B.t. var. kurstaki CAB141 and indoxacarb WP - methoxyfenozide + spinosad SC - Chlorfluazuron EC - B.t. var. aizawai CAB109, B.t. var. kurstaki CAB141 showed greater than 78% mortality of beet armyworm larvae and greater than 43% damage decrease in spring onions infested by beet armyworm. These results showed that alternative applications had higher control effect than any other applications. It was suggested that alternative applications with microbial biological agents such as B. thuringiensis might minimize the development of insecticide resistance and might be used as the environment-friendly control of the beet armyworm.

• The Korean Journal of Pesticide Science
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• v.4 no.4
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• pp.72-76
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• 2000

The study was conducted to investigate the developmental periods and effect of several insecticides on Hemiptarsenus sp., ectoparasitoid of Liriomyza trifolii. The mean length and width of egg were 0.5mm and 0.1mm. The mean length of larva, pupae, abult female, and abult male were 1.9mm, 2.0mm, 2.2mm, and 1.8mm, respectively. Developmental periods of Hemiptarsenus sp. from egg to larva at 15, 20, 25, $30^{\circ}C$ were 16.9, 8.8, 5.9, and 4.5 days, and those of pupa were 20.7, 9.7, 5.6, and 3.4 days, respectively. Based on these results, developmental threshold temperatures and effective temperatures were $9.5^{\circ}C$, 91.5 degree-days in egg-larval stage, $10.9^{\circ}C$, 142.3 degree-days in pupal stage. When several insecticides were evaluated to Hemiptarsenus sp. at the recommended concentrations, B.t WP, diflubenzuron WP, and cyromazin were negligiblly effective all life stages. Fipronil SC, cartap SP, spinosad GW were less toxic to larva and pupa, but highly toxic to adults. Abamectin EC was less toxic to all life stages, but inhibited oviposition of 50% more to Hemiptarsenus sp. female.