Insecticidal and residual effect of three pyrethroids against Sitophilus oryzae (L.) (Coleoptera: Curculionidae) on stored wheat

摘要: Abstract Laboratory tests were conducted to assess the use of pyrethroids, deltamethrin, beta-cyfluthrin and alpha-cypermethrin at rates 0.125 0.25 ppm, as grain protectants in stored wheat against rice weevil, Sitophilus oryzae (L.). For this purpose, clean untreated was sprayed with these insecticides for 6 months. During period, four bioassays carried out, order evaluate residual efficacy each pyrethroid. In bioassay, treated infested S. adults, dead insects counted after 1, 2 7 d exposure. addition, progeny production estimated on until F4 generation. The results indicated that deltamethrin beta-cyfluthrin, both significantly more efficient than other treatments. Efficacy notably higher exposure, 1 2 d. At same exposure level, 3.5 months treatment, mortality approximately 89%, 92% 86%, respectively, while corresponding percentages 97%, 83% 62%, 50%, 49% 33%. However, rate 0.125 ppm, ⩽58% all cases. treatments appearance F1–F4 generations observed, exception where only a few F1 adults noted, without subsequent generations.