Studies On Fungitoxic Plant Extracts Against Botrytis Cinerea And Other Plant Pathogens

Ninety-five species of plant materials were extracted with ethanol and the rough extracts were tested for their fungitoxity. Ninety-four siiecies df the extracts were tested for the inhibition to the mycelial growth of Botrytis cinerea. The method of inhibitory area was used to test the inhibitory effects of 91 species of plant extracts on spore germination of B. cinerea. Results showed that 40 species of plant extracts could inhibit the mycelial growth of B. cinerea in different degree. And 12 species of plant extracts preliminarily showed inhibitory effects on spore germination of B. cinerea. Twenty-five species of the plant extracts which have showed inhibitory effects in mycelial growth inhibition test and inhibiory area test were further tested on slides for their inhibitory effects on spore germination of B. cinerea. Four of the 25 species plant extracts showed equivalent strong inhibitory effects with the chemical control-?Scarlar?on the spore germination of B. cznerea. Eighty-two species of plant extracts were tested for their inhibitory effects on the mycelial growth of P infestans, 33 species had completely inhibitory effects and the other 35 species showed different inhibitory effects. Eighty-nine species of plant extracts were tested for their inhibitory effects on zoospores release of P infestans, 32 species showed completely inhibitory effects. The result of secondary screening test showed that the extract TS-26 and TS-90 had strong inhibitory effects on the mycelial growth and the spore germination of B. cinerea. The extract TS-26 and TS-49 showed strong inhibitory effects on the mycelial growth and the zoospores release of P infestans. Experiments were carried out on sovelent selection and concentration determination of the best sovelent or the proportion between different sovent and the time length for extracing to TS-26 and TS-90. The results were as follows. Eighty percent methanol or methanol acetone water (2 2 1) was used to extract for TS-26. And extracting at 30C with 150rpm shaking 2d is the moderate condition for TS-26. As for TS-90, 80% ethanol, 30C, 150rpm shaking 3d is the moderate condition. Inhibitory effects of TS-26 and TS-90 to B. cinerea were made by means of veighting dried mycelium, measurement of spore production and the middle inhibitory concentrtion (MIC). In the test of dried mycilum method, TS-26 was diluted to 100 times and TS-90 was diluted to 50 times. Both had strong inhibitoryeffects on the mycelial growth of B. cinerea, but with the decrease of the extract concentration, the inhibitory effects of the plant extracts dropped down severely The dilutions of TS-26 from 100 to 200 times inhibited the spore production of B. cinerea significantly. While the 600 times of TS-90 dilution could still inhibit the spore production of B. cinerea. The MIC of TS-26 was 270 times, and the MIC of TS-90 was 426 times. In the test of the inhibition to the zoospores release of P infestans, TS-26 was more active than TS-90. In addition, TS-26 completely inhibited the mycelial growth of Rhizoctonia cerealis, Gaeumannornyces var. fr/I/cl, B/polaris sorokiniana, Fusariurn culrnorurn and Alternaria alternata at 200 times dilution, which showed a wide inhibitory scope. While TS-90 only inhibited Rhizoctonia cerealis, Gaeurnannornyces var. fr/f/cl and Bipolar/s sorokinianat at low level, and had no inhibitory effect to Fusarium cu/rn orum and Alternaria a/tern ata at all. The physical and chemical characters of the two extracts were tested after being treated at different temperature, illumination and pH values. And the t...