Cell-wall Degrading Enzymes Produced By Fusarium Species And Their Pathogenicity To Corn Sheath

Corn sheath rot as one new corn disease developed rapidly in most corn-planting regions in China recently. It usually occurred during late growth period and infected the corn sheath, then caused irregular circular spots with grayish brown to dark brown lesions or wet rot. In this study, the activity of cell-wall degrading enzymes and toxin and pathogenicity of three Fusarium species which caused corn sheath rot have been researched in details and growth rate methods was used to estimate the toxicity of Carbendazim, Tebuconazole, Diniconazole, Flusilazole and the mixture of Carbendazim and Tebuconazole with 1:1, 2:1, based on which the field control efficiency tests were carried out. The results can be showed as follows:1. The culture conditions of cell wall degrading enzymes which produced by three Fusarium species were studied, The best culture manner was static culture; the optimal incubation time and pH of Cx was 10 d and 6, PG was 6 d and 6, PMG was 6 d and 5, PGTE and PMTE were 6 d and 9.2. The activities of PG, Cx and PMG produced by these Fusarium species were much higher than the ones of PGTE and PMTE.3. The pathogenicity and activities of extracellular wall degrading enzymes and toxin produced by F. proliferatum were more higher than that of F. moniliforme and F. graminearum.4. Four fungicides had better inhibition on F. proliferatum and the EC50 were 17.27 mg/L, 23.40 mg/L, 24.21 mg/L, 26.01 mg/L, 18.48 mg/L and 25.83 mg/L, respectively. The field control efficiency of Carbendazim, Tebuconazole and the 1:1 mixture of Carbendazim and Tebuconazole were 93.34%, 89.19% and 91.49%, the yields increase rate were 20.61%, 15.46% and 18.84%.