Research On Repelling And Insecticidal Effect Of Mint And Its Extract On Myzus Persicae

Myzus persicae is a worldwide pest.In a long period,aphid have evolved resistance to pesticides.To elucidate repelling and killing effect of mint.GC-MS was used to analyse the chemical constituents of its volatile components.Than studied the ethanol extraction effect to adults and their carboxylesterase and acetylcholinesterase activity.1.Bioassay of menthol ethanol extract on M.persicaeBy comparing the survival rate(adults on mint was 11.43% for 5d,43.33% on peach leaf and 32.86%on cabbage leaf)and the number of offspring(adults on mint was approximately 0)on the leaves,we can determine mint is the non-host plant of aphid.Design field experiment(In the first stage,the number of aphids,in mint plot with mechanical injury,is inferior to the other.In the second test,the number of adults and nymphs in mint plot is inferior to others.)The results of bioassay showed that effect of feeding resistance 100mg/m L the highest feeding resistance was up to 85.71% after 24 h,and the concentration in the feeding resistance was 40.5816mg/m L.The mortality death rate was 72.41% at 48 h.At 36 h,mortality of menthol extract concentration on aphid was 39.38%.2.Mechanism of action of mint ethanol extract on peach aphidAt the same time,Ach E in M.persicae was inhibited at first and then increased with the increase of extract concentration.The activity of the treatment enzyme with the concentration of 50 mg/ m L is the highest,the Ach E activity was 0.26±0.01 U/mgprot at 12 h,0.29±0.04 U/mgprot at 24 h,and 0.36±0.02U/mgprot at 36 h.After treatment for 12 h and 24 h,the enzyme activity of carboxylanase(Car E)increased with the increase of the concentration of extract,and increased first and then decreased after treatment for 36h: CK enzyme activity was 18.98±2.21 u /mgprot,12.5mg/m L was 25.25±5.40u/mgprot,25mg/m L was 31.05±5.03 u /mgprot,and 50mg/m L was 18.77±2.77 u /mgprot.3.Analysis of effective components of mint odour volatile matter by SPMEThe groups with high content of menthol-scented volatiles were divided into l-carvone,d-limonene,beta-pinene,1-methyl-4-(1-methyl-ethyl)-1,4-cyclohexadiene,eucalyptus alcohol,1-carvyl acetate,-isoparolefin,sabinene and 3-octanol.4.Study on the Antifeedant Effect of the Mint Extract on Myzus persicae by EPGCompared with the control group,the duration of E2 and phloem feeding(E1e+E1+E2)in the50mg/m L mint extract group was(166.45 ±105.72min),accounting for(0.58% ±0.35%)of the total time and(4958.68 ±1168.55;17.22% ±3.94%)min in the control group,the difference was significant(p < 0.05),which indicated that the feeding time of peach aphid was significantly less than that of the control group,which decreased the frequency and time of piercing mesenteric cells.The number of pd waves in the experimental group(2),pd waves duration(9.87min)was lower than that in the control group(5.43;28.42min).The frequency and time of piercing mesenteric cells were decreased by peach aphids in the experimental group.The duration of E2 wave in the experimental group and the control group was148.35 min.At 4889.97 min,E2 wave accounted for 79.60% of the total time to enter the phloem.The duration of oral acupuncture in phloem was(166.45 min.4958.68min),stylet in the phloem activities in the total time percentage(0.006%;0.17%),and the number of np waves after the first phloem activity of oral needles(2.00;8.71),the difference was significant(p < 0.05),In the experimental group,E2 wave,duration of oral acupuncture in phloem,and number of np wave after the first phloem activity of oral acupuncture were all significantly less than those of the control group.The feeding time of peach aphid in the experimental group was significantly less than that of the control group.The feeding frequency of peach aphid decreased after the first phloem feeding.