Study On Inhibitory Effects On Tomato Fungal Diseases Of Antifungal Extracts From Garlic

In this study, antifungal extracts of garlic (Allium sativum l.) were used to investigateinhibitory activities on 19 plant fungal pathogens, including Alternaric solani, Fulvia fulva,Botrytis cinerea and Colletotrichum coccodes et. Al. Extract methods, extractsstability and antifungal activity were tested systematically by inhibitory zone methods andgrowth velocity methods. In conclusion:1. It has been observed that the optimal extract conditions were fresh garlic was crushedfirstly, and incubated at 28 ℃ for 30-60 minutes to be digested by alliinase. Next, theincubated garlic was extracted by ethyl acetate under shaking for 12 hours at 28 ℃. TLC andHPLC results indicated that the main fungal inhibitory components were allicin. The volatilecomponents have the highest inhibitory activity.2. The factors to effect the antifungal activities of garlic extracts were studied. Theresults showed that the antifungal activities reduced by mercapto-compound, hightemperature (60℃), alkaline and concentrated acid treatment. However, the antifungalactivities could be enhanced by compound which contained disulfide bond.3. It has been observed that the garlic extracts had comprehensive inhibitory activities onplant pathogenic strains with genus specification to some extent. Results indicated that theextracts from garlic effectively inhibited the fungal pathogens which can generate abundantsmall spores with a long vegetative period. However, garlic extracts has a low antifungalactivity on the fungal pathogens that can generate abundant thick-walled spores with a shortvegetative period.4. It has been observed that the inhibitory activity of garlic extracts is more effective thanDuojunling. The garlic extract emulsion was made and antifungal activity was compared withAimiao emulsion and the Duojunling powder by growth velocity methods for four pathogenicfungus (Colletotrichum coccodes, Botrytis cinerea , Fulvia fulva , Alternariasolani) of the tomato. Results showed that the antifungal activity of the Aimiao butter wasmarkedly higher than that of garlic extract emulsion and Duojunling powder, and theantifungal activity of garlic extracts emulsion was a little more effective than that ofDuojunling powder. The garlic extract emulsion has a more effective activity onColletotrichum coccodes than Botrytis cinerea, Fulvia fulva and Alternaria solani.Pathogenic spore and tomato seed germination test indicated that garlic extraction emulsioncould promote tomato seed germination and growth at 1000-10000 dilution and could be usedin field bio-control at 150-1200 dilution.