The Lethal Effects Of Spinosad,Deltamethrin And Malathion Against Callosobruchus Chinensis(L.) And Callosobruchus Maculatus(F.)

Callosobruchus chinensis (L.) and Callosobruchus maculatus (F.) (Bruchididae, Coleoptera) are 2 kinds of important stored beans insect pestsdistributed all over the world,In this paper, the lethal effects of spinosad against C chinensis and C. maculatus for different development stages including egg stage, inside bean stage and audul stage.; lethal effects of spinosad, deltamethrin and malathion against 2 kinds of weevil adults under different temperatures and treatment times; control effects of spinosad combined seperatedly with deltamethrin and malathion on 2 kinds of bruchids were researched, the effect of spinosad on acetylcholinesterase activity of C. chinensis.was also studied. All the results can provide technical reference for the use of spinosad and other two grain protectants against C. Chinensis and C. Maculatus.1. Toxicity test of spinosad and two other protectants against C. chinensis and C. Maculatus1.1 Toxicity test of spinosad against C. chinensis and C. maculatus on different developmental stagesLC50 of three development stages for C. chinensis and C. maculatus at 30℃, and 24 h treatment time were measured by mixing the spinosad with mungbean seeds... The results showed the LC50 of C. chinensis for egg stage, inside bean stage and adult stage were 0.4762 mg/kg, 0.4762 mg/kg, and 0.6605 mg/kg; respectively. For C. maculatus, the LC50s of three developmental 0.4549 mg/kg,0.4315 mg/kg, and 0.6577 mg/kg, respectively. The results proved that spinosad had strong lethal effects for C. chinensis and C. maculatus.The insecticidal activity order to the three developmental stages of C. chinensis was:egg stage>inside bean stage>the adult stage; and for C. maculatus:inside bean stage> egg stage> the adult stage. There was no significant toxicity difference between egg stage and inside bean stage, and lethal effect of spnosad against 2 kinds of bruchid adult were the poorest compared with egg and inside bean stages, weakest.1.2 Toxicity tests of deltamethrin and malathion on the adult stage of two bruchid LC50 of deltamethrin and malathin agaist adults of C. chinensis and C. maculatus were tested at 30℃and 24h treatment. The results showed that the deltamethrin and malathin had strong lethal effect on two bruchid adults. The lethal effect for C. chinensis was stronger than that for C. maculatus; and the lethal effect of deltamethrin was stronger than that of malathion. The LC50 of deltamethrin for the audlt stage of C. chinensis and C. maculatus were 0.0608mg/kg and 0.0687mg/kg; respectively. Meanwhile, the LC50 of malathin for the audlt stage of C. chinensis and C. maculatus were 3.0237mg/kg and 4.2659mg/kg, respectively.1.3 Lethal effect of three protectants on the adults of two bruchid at different temperature and treatment timeThe lethal effects of three protectants against the adult of C. chinensis and C. maculatus at the different tempetures and treatment time were studied. The results showed 1 mg/kg spinosad can control the adults of C. chinensis and C.maculatus effectively. At the same temperature, with the increasing of treatment time, the lethal rate of spinosad against C. chinensis and C. Maculatus increased significantly. However, t tempeture and the interaction between temperature and treatment time had no significant influence on the adult mortality.. Three protectants had strong lethal effects againsttwo bruchid after 24h treatment, and the effect of deltamethrin was the best, followed by malathion and spinosad. Three protectants had strong lethal effects on two bruchid at 26℃under different treatment time, and the effect of deltamethrin was the best, followed by malathin and spinosad. At 20～23℃, as temperature increased, the lethal effects of three protectants on C. chinensis and C.maculatus increased significantly, but from 26℃to35℃, the lethal effects of three protective agents C. chinensis and C. Maculatus kept basically unchanged.2 Control effects of spinosad with deltamethrin or malathin in two bruchidAt 30℃, control of 2 kinds of bruchids was researched by using spinosad, spinosad+ deltamethrin, and spinosad+malathio. Under the condition of simulative real storage at 30℃, control efficacy was researched by using spinosad, spinosad+deltamathrin; and spinosad+malathion. The results showed 1.Omg/kg and 5.0mg/kg doosage can control 2 kinds of bruchids effectively with 100% control efficacy to F1 generation after 30days.3 Effect of spinosad on acetylcholinesterase activity in C. chinensis.The results showed that in vivo condition, spinosad had no significantly inhibition on acetylcholinesterase activity in C. chinensis and inhibitory rate kept unchanged. The inhibition rate were only 0.67% after 8 h at 0.5mg/L, and the inhibition rate after 24 h were the highest,only 1.87%. These showed that Spinosad had no effect on AchE activity under vivo conditions. In vitro conditions,the effect of spinosad on activity of AChE wsa small, after pesticidetreatment, AChE activity increased slightly, and the difference was not significant compared with the control. There was no significant difference for AchE activity after diffferent doasge of spinosad treatment.