Studies On Herbicidal Activity Of Metabolites From Botrytis Cinerea And Isolation Of Active Substance

Eleven isolates of Botrytis cinerea collected from different regions and hosts were cultured in Czapek-Doxbiotion liquid media and their metabolites were used as crude toxin to test their toxicity on two crops, tomato and pepper, and two weeds, Amaranthus retroflexus and Digitaria sanguinalis. The metabolites generally showed certain toxicity on the root and bud growth of plant seeds and the seeding growth of plants tested, but different isolates exhibited different activities. Isolate BC1 and BC4 had the highest toxicity, isolate BC3,BC11 and BC5 took the second place, the other isolates had less activities. The isolates tested that had higher toxicity on root growth of plant seeds often had higher toxicity on bud growth of plant seeds and the seeding growth of plants. It had also shown that the isolates tested that had higher toxic activity on tomato and pepper also had higher herbicidal activity on Amaranthus retroflexus and Digitaria sanguinalis.The fitting culture conditions for isolate BC4 producing more toxin were Improvement Fries and Czapek-Doxbiotion(I) culture medium , culture time for thirty-five days, pH for 6, culture temperature for 25 , still cultivation, and that the juice of tomato and pepper cannot improve herbicidal activity on Amaranthus retroflexus.The metabolites of isolate BC4 inhibit the seeding growth and caused necrotic spots on leaves of many weeds according the result of bioassay. These weeds are Amaranthus retroflexus, Digitaria sanguinalis, Convolvulus arvensis, Pharbitis nil Choisy, Chenopodium album, Setaria viridis, Echinochloa crusgalli, Portulaca oleracea, and Eleusine indica. Amaranthus retroflexus was most susceptible in tested weed.Culture filtrate of Botrytis cinerea was extracted with ethyl acetate, the ethylacetate extracts were condensed, Condensed liquid was called crude toxin, then crude toxin were fractionated three times by column chromatography(CC) as described in the material and methods. One herbicidal fraction was collected. The fraction was further purified by high performance liquid chromatography (HPLC). then a active peak taking on acute and symmetrical shape was collected.