BIOLOGICAL CONTROL OF WILT AND ROOT ROT DISEASES OF SAGE PLANT

Ten bacterial strains were evaluated for their effect on the growth of Fusarium oxysporum, Pythium ultimum, Fusarium solani and Rhizoctonia solani (the causal agents of sage wilt and root rot diseases) in vitro. Only four bacterial strains, (Pseudomonas fluorescens strains L2, P5 and Y8 as well as BM strain of Bacillus megatarum) gave strong inhibition against the tested fungi. Bacillus megatarum BM and Pseudomonas fluorescens Y8 as soil drench application were the best strains which significantly reduced disease incidence, internal root browning as well as foliar wilt rating of sage seedlings infected with Fusarium oxysporium. Meanwhile, only strain Y8 expressed the highest reduction in root rot caused by each pathogen alone or in mixture. Under field conditions, application of strain Y8 as soil drench treatment increased survival of sage plants. All bacterial strains reduced wilt incidence, however strains BM and Y8, applied as seedling soaking treatment, reduced wilt incidence. On the other hand, most antagonistic bacteria showed non significant effect in reducing root rot incidence. Plant fresh weight, dry weight and the amount of oil per plant were not significantly increased compared with non-treated control. It is worthy to mention that oil percentage was increased significantly with the application of all bacterial strains applied as soil drench or seedling soaking treatment.