| In this paper, laboratory studies were conducted to screen the insecticidal activity of oragnic solvents extracts from various Chinese medicinal herbs on several insect pests, which included Helicoverpa armigera, pieris rapae L. and prodenia litura, the aphids, Sitophilus zeamais mutschulsky and the antifungal activity on the three plant pathogen (fusarium graminearum schw, fusarium oxysporium and physalospora piricola nose).The main results were summarized as following.l.The extracts from Chinese herb H and M were founded to show fairly strong antifeedant activities against the 3th-instar larvae of Helicoverpa armigera .After 48 hours , the antifeedant rate of 97.2% and 85.3% were achieved with the treatment of them. Compared with other organic solvent extracts ,the methanol extracts from M showed better antifeedant activity against the 4th-instar larvae of Helicoverpa armigera with the AFC50 value of 1.788g/L after 24 hours .The growth of the larvae of Helicoverpa armigera were inhibited by the extracts from F ,which postponed the larvae stage of Helicoverpa armigera by about five days .The genin derive from F was shown to have little effect on the growth of the larvae of Helicoverpa armigera.2.The extracts from A were found to have strong antifeedant and poisonous activities against pieris rapae L.The acetone and 50%acetonitrile extracts were shown to exhibit better bioactivities than other organic solvent extracts .For the 3th-instar of pieris rapae L, their AFC50 values were 0.525g/L, 0.700g/L respectively and the LC50 values reached 29.36mg/L and 53.34mg/Lafter 24 hours .The AFC50 and LC50 values of the crude diethyl ether extract from A were 0.973g/L,116.68mg/L respectively .3.The 4th-effluent, 5th- effluent were separated from A on a normal-phase silica column,in which activity substance existed . For the 3th-instar larvae of pieris rapae L., the AFC50 values of these two effluents were 0.574g/L,1.82g/L and the LC50 value were 19.42mg/L,31.91mg/L after 24 hours respectively .4. The extracts from H and A were found to exhibit strong antifeedant effects on the 3th-instar larvae of prodenia litura The antifeedant rates of 96.45% and 85.51% were observed respectively after 24 hours of treatment .For the 4th-instar larvae of ,their AFC50 values were 0.464g/L, 1.478g/L respectively.5.The repellent activities of the extracts from H,C,F,J were evaluated against Sitophilus zeamais adults with average repellency rates being above 80%.Whatsmore ,their repellency effects were very stable. Significant reduction in growth rate of S.zeamais adults were founded with the treatment of the extracts from H and M and the growth inhibitory effect of extract from M reached 79.8%.The extract from M demonstrated fluctuated repellency to the S.zeamais adults with the repellency rate being just 51.3% after 2 days and reaching 95.7% after 3 days.6.The extracts from C and E were found to have strong antifeedanteffects on the aphids .The antifeedant rates were 79.1%,84.6% after 48 hours .The extracts from E and P exhibited good contact toxicity to the aphids .After 72 hours , their rectified moralities were 68.0%, 84.0% respectively . The rectified morality rate of extract from P to the aphids was above 60% after 8 hours .7.The strong antifungal activities of the extracts from A and E were observed .After 72 hours , their inhibitory rates of above 80% to Fusarium graminearum Schw. and 70% to fusariam oxysporium were reported in this study .At the same concentration ,all the extracts were tested to show little effects on physalospora piricola nose except that the inhibitory rate of E to it was up to 80%.The acetone and 50% acetonitrile extracts of A were demonstrated to have stronger antifungal activities than other organic solvent extracts of A. At the concentration of 3g/L, the inhibitory rates of the acetone and 50% acetonitrile extracts to Fusarium graminearum Schw. were 100% after 48 hours ,these of the chloroform and diethyl ether extracts were 95.3%,90.6% respectively. After 96...
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