Monitoring Insecticide Resistance Development in Beet Armyworm, Spodoptera exigua(Hubner)(Lepidoptera: Noctuidae)

摘要

Field collected larvae of beet armyworm, Spotoptera exigua(Hubner)were reared and evaluated for resistance against cypermethrin 10 EC, neem extract(Azdirachtin 0.1/100)and Bacillus thuringiensis Berliner var. kurstaki(53,000 SU per mg)for 12 generations under laboratory condition by using leaf dip Bioassay. Cypermethrin showed LC_50 value of 251 ppm at F-1 generation and decreased gradually to Onward generations resulting LC_50 value of 90 ppm at F_12 generation for non-selection, whereas LC_50 Increased rapidly with a value of 8625 ppm at F_12 generation under selection pressure.