Study On Insecticides Control Of Ephestia Elutella(Hübner)

Ephestia elutella?Hübner??Lepidoptera,Pyralididae?is a widely tobacco storage pest occurrenced in the tobacco storagehouse.It is only second to the most damaged species,Lasioderma serricorne?Fabricius?.It distributes widely in each tobacco production area of the world.It also widely distributed in China,particularly occuring in Guizhou and Yunnan provinces.E.elutella mainly harmed tobacco at larvae stage by parasites in the first roasted tobacco leaves for feeding,and the contamination of the insect-derived foreign bodies causes the quality of the tobacco leaves to be seriously degraded.The degree of harm in each tobacco-growing area is very different.The tobacco industry at home and abroad has always attached the utmost importance.Therefore,on the one hand,this study explored the virulence of E.elutella by low-toxicity and new insecticides,and clarified the sensitivity of Concentrations to different types of agents,and selected the best E.elutella.The protective agent and the effect of sub-lethal concentration of deltamethrin and indoxacard on the biological characteristics of E.elutella provide a reasonable reference for the sustainable management of E.elutella.On the other hand,the fumigating activity of the mixed preparation of ethyl formate and methyl isothiocyanate on the insect state of E.elutella was studied,aiming at finding a highly toxic substitute agent.Provide a favorable theoretical basis to provide a reference for the sustainable management of E.elutella.1.Sensitivity of E.elutella to 12 InsecticidesIn order to effectively control the damage of E.elutella during tobacco storage,the susceptibility of E.elutella 3th larvae,adults and eggs to 6 low-toxicity insecticides was determined by leaf impregnation and egg impregnation,and assess the potential application of 6agents for E.elutella.The results showed that the fenoxycarb and deltamethrin treated on E.elutella had high toxicity(The LC₅₀ of 3^th larva were 0.60 mg.L^-1,2.70 mg.L^-1,respectively;The LC₅₀ of adults were 2.39mg.L^-1,5.24 mg.L^-1,respectively;The LC₅₀ of eggs were 2.39 mg.L^-1,5.24 mg.L^-1,respectively).Metaflumizone had the lowest toxicity to E.elutella,and its LC₅₀ to the 3^thh larva,adults and eggs were 37.47 mg.L^-1,486.27 mg.L^-11 and 946.81 mg.L^-1,respectively.the virulence(LC₅₀)of Beauveria bassiana,Metarhizium anisopliae,Beauveria brongniartii,Avermectin,matrine and pyrethrin to the 3^th instar larvae of E.elutella was 1.79×10⁸ cfu/L,2.08×10⁸ cfu/L,4.22×10⁸ cfu/L,0.23 mg/L,19.33 mg/L,12.47 mg/L.Therefore,at late-stage larvae of E.elutella?usually out of tobacco packets to pupate?or adults,low-toxic fenoxycarb,deltamethrin and three agents?Beauveria bassiana,avermectin and pyrethrin?can be used for surface treatment in warehouse areas,which would reduce the population of E.elutella in the warehouse.2.Fumigation activity of ethyl formate against plus methyl isothiocyanate E.elutellaIn order to effectively control the damage of E.elutella during tobacco storage,the susceptibility of E.elutella to several biological insecticide and a fumigant were determined by leaf impregnation and the wide-mouth bottle closed fumigation method,and assess the potential application of 7 agents for E.elutella.The results showed that ethyl formate and methyl isothiocyanate mixing fumigation on the 3^th instar larvae of E.elutella,had highest toxicity is new formulation of 85%ethyl formate plus 15%methyl isothiocyanate,the LC₅₀ is 18.32?L/L,and the lowest toxicity is ethyl formate,The LC₅₀ of 56.32?L/L.And the fumigation activity of the mixture of ethyl formate and methyl isothiocyanate to four states:adults>pupas>young larvas>old larvas.Therefore,the new formulation of ethyl formate plus methyl isothiocyanate has a commercial potential as an alternative fumigant for use on E.elutella.3.Effects of sublethal concentrations of deltamethyrin on the biological characteristics of E.elutellaIn order to investigate the sublethal effect of deltamethrin on E.elutella,the effects of sublethal concentration of deltamethrin(LC₁₀ and LC₂₅)on the development and reproduction of E.elutella were studied by tobacco leaf impregnation,and analyzed datum by age-stage-specific life tables method.The results showed that the average single female egg production(LC₁₀:56.79,LC₂₅:46.31)of E.elutella F₀ after sublethal concentration treatment was significantly less than that of the control?75.83?;the pre-oviposition(LC₂₅:1.33 d)was significantly longer than the control?1.02 d?;the difference between the survival period of the treated female and male insects and the control was significant.After sublethal concentration treatment,the survival rate of E.elutella F₁ was significantly decreased(LC₁₀:12.50%,LC₂₅:16.26%),but the development of LC₂₅ treated eggs,1st instar larvae,3rd instar larvae,5th instar larvae,7th instar larvae and pupa there was no significant difference between the duration and the control.The duration of the 2nd instar larva,4 th instar larvae and 6 th instar larvae was significantly prolonged?0.80,1.24,0.70d?;the adult stage of the LC₂₅ treated group was significantly longer than the control by 3.16 days.At the same time,LC₂₅ treated females and males get the shortest lifespan.Studies have shown that sublethal concentrations of deltamethrin can inhibit the growth and reproduction of E.elutella.4.Effects of sublethal concentrations of indoxacard on the biological characteristics of E.elutellaIn order to investigate the sublethal effect of indoxacard on E.elutella,the effects of sublethal concentration of indoxacard(LC₁₀ and LC₂₅)on the development and reproduction of E.elutella were studied by tobacco leaf impregnation,and analyzed datum by age-stage-specific life tables method.The results showed that the average single female egg production(LC₁₀:51.57,LC₂₅:46.66)in the F₀ generation after treatment with E.elutella was significantly less than that of the control?75.83?;pre-ovulation(LC₂₅:1.38 d)Significantly longer than the control?1.02 d?;there was no significant difference in the developmental duration of the eggs,3rd instar larvae,4th instar larvae,5th instar larvae,7th instar larvae and pupa of E.elutella F₁ treatment after sublethal concentration treatment.However,the duration of larvae in the LC₂₅ treatment group was longer than that of the control,and the difference was significant.At the same time,the life expectancy of LC₂₅-treated females and males was the shortest,but the difference between the three treatments was not significant.Studies have shown that sublethal concentrations of indoxacard can inhibit the growth and reproduction of E.elutella.