| Spider mite is a kind wide hazards,difficult to control biological group recognized by the world,and the use of botanical pesticide has been recognized as environmental security means for prevention and control of spider mites.Mirabilis jalapa contain a rich chemical composition,in which,trigonelline and rotenone compounds have been found and show insecticidal activities,based on these facts,this paper studied the acaricidal activity of mirabilis jalapa,to clarify the toxic activity to spider mites,the influence on some enzyme activities and the impacts on host plants,which will provide a scientific basis for developing acaricide from mirabilis jalapa.Contact Killing experiment was carried out on female adult mites and eggs of two-spotted spider mite with different solvent extracts from mirabilis.The results showed that ethanol extracts,methanol extracts,ethyl acetate extracts and petroleum ether extracts of mirabilis were all toxic to female adult mites and eggs,and the activity of ethanol extracts was the most powerful.The LC50 of mirabilis ethanol extracts to the female adult mites was 4.07 mg/ml,and the LC50 to eggs was 52.96 mg/mL,Mirabilis ethanol extracts had a better oviposition inhibition on mites,and with a dose dependent trend.When treatment concentration was 16mg/ml,the extracts had inhibitory effect on the rate of oviposition inhibition of 24 h and 48 h at about 97%Tetranychus was treated with the maximum tolerable dose of 1.2MG/ML in way of contact killing,the changes of the enzyme activities of mites were determined after 4h,8h,12 h,16h,20 h and 24 h respectively.The results showed that the activities of female mite protein enzymes,esterase and Na+,K+-ATPase in the treatment group were showed decreased trends,and the activity of glutathione sulfhydryl transferase(GST)rised first and then descended,but higher than that of the control group within 24 h.The results showed that mirabilis ethanol extracts had an effect on the activities of several enzymes of two spots mites,suggesting that the mechanisms of killing mites was related to these enzymes.The mirabilis methanol extracts of concentration is 5mg/m L,10 mg/m L and15 mg/m L were prepared,and were used to treat soybean,eggplant seeds,the parameters of seed germination rate,germination index,root length and fresh weight were determined.The results showed that the germination rate and germination index of soybean were the highest when mirabilis methanol extract was 5mg/ml,indicating promoting the germination of soybean seed.The root length and fresh weight of soybean seedlings were inhibited obviously when the mirabilis methanol extract was 10mg/ml and 15mg/ml.Mirabilis methanol extract inhibited the germination rate,germination index,root length and average fresh weight of eggplant,when the concentration of mirabilis methanol extract was 5mg/ml,the inhibitory effect was obvious,and increasing concentration did not further increase the inhibitory effect.Low concentration of mirabilis methanol extracts promoted the formation of chlorophyll in cucumber seedlings,and the high concentration of mirabilis methanol extracts inhibited the formation of chlorophyll in cucumber seedlings.The results showed that the mirabilis methanol extract had an complex effects on the germination and growth of soybean and eggplant seeds and the chlorophyll content of cucumber seedlings,and it was suggested that the development of mirabilis pesticide should take fully into account the possible adverse effects on crops. |
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