| The Sitophilus zeamais is one of the most severe early stored grain pests in the world,and it is listed as the number one stored grain pest in China food sector;Tribolium castaneum is an important late-stage storage pest,with diverse eating habits and wide range of hazard.The bio-sourced grain storage protective agent is a pollution-free green pesticide,and the pests aren't easy to develop drug resistance,which meets the requirements of the new era for the green prevention and control of stored grain pests.In this study,the filter paper drug film method was first used to determine the contact effect of seven biological source preparations on important stored grain pests such as S.zeamais and T.castaneum,then determine the contact and poison kill activity of the selected two highly effective biological source preparations against two kinds pests,and determine its optimal dosage;meanwhile,the fumigation effect of eleven plant essential oils on two stored grain pests was determined by the sealed fumigation method of triangular flask,and determine its optimal concentration;at last,Choose the better bio-source preparations and plant essential oils for simulated storage test,verify the effect of real warehouse application.The main results of the research are as follows:1 Preliminary screening of the control effects of seven biological preparations on S.zeamais and T.castaneumThe contact toxicity of seven biological agents,including spinetoram,azadirachtin,and osthole,on the adults of S.zeamais and T.castaneum was determined at the dose of 47.16 ?g/cm2,the results show:there were significant differences in contact killing effects of different biological agents on the two pests,among which spinetoram had the best effect,after 72 h treatment,the corrected mortality of S.zeamais was 73.46%,and that of T.castaneum was 61.72%;the second is osthole,after 72 h treatment,the corrected mortality of S.zeamais was 62.15%,and that of T.castaneum was 54.28%.2 Contact and toxic action of two highly effective biological source preparations against S.zeamais and T.castaneum and optimal dosageFive treatment doses of 5.90,11.79,23.58,47.16 and 94.31?g/cm2 were designed respectively,the contact action of two high-efficiency biological agents screened in the early stage on the adults of S.zeamais and T.castaneum was determined by filter paper film method,the results show:at a treatment dose of 94.31?g/cm2,after treatment for 72 h,the corrected mortality rates of spinetoram to S.zeamais and T.castaneum were respectively 85.56%and 82.54%,the corrected mortality rates of osthole to S.zeamais and T.castaneum were 75.43%and 67.32%,respectively.The LD50 value of the S.zeamais and T.castaneum treated with spinetoram for 72 h was 18.95 ?g/cm2 and 24.98?g/cm2,respectively,the LD50 value of the S.zeamais and T.castaneum treated with osthole for 72 h was 31.99.g/cm2 and 44.49 ?g/cm2,respectively,with the prolongation of contact time,LD50 value decreased gradually.Five treatment doses of 0.25,0.50,1.00,2.00 and 4.00 mg/kg were set respectively,the toxicity effects of two highly effective biological agents on S.zeamais and T.castaneum were determined by grain mixing method,the results show:at a treatment dose of 4.00 mg/kg for 15 days,the corrected mortality rates of spinetoram to S.zeamais and T.castaneum were respectively 99.72%and 90.53%,and the corrected mortality rates of osthole to S.zeamais and T.castaneum were respectively 92.91%and 83.86%;After 15 days of spinetoram treatment,the LD50 value of S.zeamais was 0.32 mg/kg,and the LD50 value of T.castaneum was 0.60 mg/kg;after 15 days of osthole treatment,the LD50 of S.zeamais was 0.65 mg/kg,and the LD50 value of T.castaneum was 0.99 mg/kg.Therefore,in the next simulated real warehouse test,it was initially determined that the most suitable dosage of the two agents,spinetoram and osthole,for the prevention and control of stored grain S.zeamais with the grain mixing method was 4.00 mg/kg.3 Preliminary screening with eleven plant essential oils against S.zeamais and T.castaneumThe fumigation concentration of essential oil was set at 30 ?L/L,the fumigation activities of eleven plant essential oils from cinnamon oil,wormwood oil and clove oil on S.zeamais and T.castaneum were determined,The results showed that the fumigation effects of oregano essential oil and cinnamon essential oil on S.zeamais and T.castaneum were significantly higher than the other nine plant essential oils(P<0.05),the mortality of pests increased with the prolongation of fumigation time.Fumigation treatment for 72 h,the corrected mortality of oregano essential oil to S.zeamais and T.castaneum were 86.67%and 91.42%,respectively,and the cinnamon essential oil to S.zeamais and T.castaneum were 93.26%and 82.89%,respectively.4 Fumigation effects and optimal dosage of two high-efficiency plant essential oils against S.zeamais and T.castaneumFour treatment concentrations of 10,20,30 and 40 ?L/L were designed,the bio-activities of two plant essential oils against S.zeamais and T.castaneum were determined by closed flask fumigation.The results show:after 48 hours of fumigation with a concentration of 40 ?L/L,the corrected mortality rates of cinnamon oil and oregano oil on S.zeamais were 95.86%and 93.18%,respectively,and the corrected mortality rates on T.castaneum were 81.32%and 72.45%,respectively.The fumigation effect of the two kinds of essential oils increased significantly with increasing treatment concentration,showing a significant dose effect.After fumigation for 72 h,the LD50 of cinnamon oil and oregano oil against S.zeamais adult was 14.36 ?L/L and 15.51 ?L/L,respectively,and the LD50 of cinnamon oil and oregano oil against T.castaneum adult was 14.42 ?L/L and 12.39 ?L/L,respectively.The results showed that the two essential oils had strong fumigation effects on the adults of S.zeamais and T.castaneum.Therefore,it is preliminary determined that the recommended standard dosage of plant essential oils to control S.zeamais is 40 ?L/L in the simulated real warehouse test.5 Control effects of two biological source preparations and plant essential oils against S.zeamais in simulated real warehouse experimentA plastic drum with a volume of 60 L was used as a simulated test warehouse,according to the results of toxicity test in laboratory,the dosage of spinetoram and osthole were set at 4.00 mg/kg,cinnamon essential oil(inert powder as carrier)was set at three concentration gradients of 200,400 and 600 ?L/L,putting 40 kg wheat in each test treatment barrel,the control effects of different pesticide treatments on the actual warehouse against S.zeamais were determined.The results show:after 60 days of treatment,spinetoram had the most obvious inhibitory effect against S.zeamais,reaching 86.8%;after 90 days of treatment,the control effect of cinnamon essential oil with 600 ?L/L concentration was the highest,still reaching 86.4%. |
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