BIOLOGICAL CONTROL OF RICE BLAST DISEASE WITH ANTAGONISTIC BACTERIA UNDER EGYPTIAN CONDITIONS

Forty two bacterial isolates were isolated from rice leaves of dif­ferent Egyptian rice cultivars and some other plants in 1995. Morpholog­ical characters of both colony and cell shape, reaction of Gram Staining and KOH test as preliminary identification tests showed that, most of the isolates belong to Bacillus app. and Pseudomonas spp. More confir­mative identification tests are needed. Twenty isolates showed inhibitory effect against Pyricularia ory­zae Cay., the causal organism of blast disease in both laboratory and greenhouse tests, sixteen isolates showed the highest mycelial reduction ranging from 53.6 to 40.5%. In greenhouse tests,all isolates were effec­tive comparing with the check; however, 14 of them were effective for minimizing blast disease infection under all application methods (seed treatment, spray 3 DBI and 3 DAI).Seven isolates were more effective when used as seed treatment or sprayed 3 DB1. On the other hand, three other isolates were effective as seed treatment and spray 3 DAI. Regardless of the insufficient effect under laboratory test, some isolates showed satisfactory effect under greenhouse test.