Safety Evaluation On Afidopyropen And Nitenpyram To Two Main Ladybirds Enemies In Southern Xinjiang Cotton Fields Based On Sublethal Effects

Pests in cotton fields in Xinjiang seriously threaten the yield of cotton,which seriously threatens the yield of cotton.With the enhancement of people’s awareness of health and environmental protection and the resistance of pests to insecticides,biological control has received attention.However,insecticides can also have a negative impact on natural enemies while killing pests,insecticides at lethal doses can cause natural enemies to die.Although natural enemies do not die at sublethal doses,life activities such as longevity and fecundity are affected,which seriously affects the effect of biological control.In this paper,the sublethal effects of the new biological pesticide afidopyropen and the neonicotinoid insecticide nitenpyram on the dominant natural enemies of the cotton field in southern Xinjiang were determined.In this paper,the sublethal effects of the new biological pesticide afidopyropen and the neonicotinoid insecticide nitenpyram on the dominant natural enemies Coccinella undecimpunctata and Hippodamia variegata of the cotton field in southern Xinjiang were determined.The research results are as follows:1.Toxicity determination of afidopyropen and nitenpyram to C.undecimpunctata and H.variegataThe results showed that the LC₁₀and LC₃₀of afidopyropen were 42.19 mg/L and 96.53 mg/L,the LC₁₀and LC₃₀of nitenpyram were 9.20 mg/L and 14.51 mg/L to the 3rd instar larvae of C.undecimpunctata.The LC₁₀and LC₃₀of afidopyropen were 17.85 mg/L and 33.06 mg/L,the LC₁₀and LC₃₀of nitenpyram were 3.58 mg/L and 6.72 mg/L to the 3rd instar larvae of H.variegata.2.Effects of afidopyropen and nitenpyram on the developmental duration of C.undecimpunctata and H.variegataThe development time of the 3rd instar larvae of C.undecimpunctata and H.variegata after treatment with LC₁₀and LC₃₀of afidopyropen and nitenpyram was 2.15 d and 1.75 d compared with the control group,It was prolonged by 0.17 d,0.53 d and 1.12 d,1.22 d and 0.33 d,0.36 d,0.43 d and 0.62 d respectively;Compared with the control group of 17.13 d and 14.36 d,the pre-adult stage was prolonged by 0.60 d,0.99 d,2.58 d,2.80 d and 0.92 d,1.13 d,1.56 d,1.74 d,both concentrations of the two insecticides prolonged the pre-adult development time of C.undecimpunctata and H.variegata,and the effect of nitenpyram was more obvious than that of afidopyropen.3.Effects of afidopyropen and nitenpyram on the life parameters of C.undecimpunctata and H.variegataCompared with the control group,the life span of female C.undecimpunctata was shortened to 42.58 d by nitenpyram LC₃₀treatment,and the life span of male was shortened to 34.11 d by45.18 d in the control group,the number of eggs laid by females decreased by 38.39%.Compared with the control group（50.63 d）,the longevity of females treated with nitenpyram LC₁₀,LC₃₀decreased by 14.38%and 23.92%.The number of eggs laid by female H.variegata in afidopyropen LC₃₀,and nitenpyram LC₁₀,LC₃₀treatment groups was significantly reduced by7.94%,50.37%and 57.57%,compared with the control group.The effect of nitenpyram on the life history parameters of the two ladybugs was longer than that of afidopyropen.4.Effects of afidopyropen and nitenpyram on population growth parameters of C.undecimpunctata and H.variegata r,R₀of C undecemlineata were significantly decreased after treatment with afidopyropen LC₃₀,nitenpyram LC₁₀and LC₃₀.Nitenpyram LC₁₀and LC₃₀significantly reduced R₀of H.variegata.The sublethal concentration LC₁₀and LC₃₀of afidopyropen and nitenpyram significantly reduced r of increase of H.variegata.The two concentrations of nitenpyram significantly prolonged T of the two ladybirds and significantly reducedλ.Compared with afidopyropen,nitenpyram had a more significant effect on the population growth parameters of ladybird beetles.The above results showed that the sublethal concentrations of afidopyropen and nitenpyram had a negative effect on the life table parameters of C.undecimpunctata and H.variegata,however,the negative effect of afidopyropen on ladybugs was much lower than that of nitenpyram.