Efficacy of VAM fungi and antagonistic bacteria against onion basal rot incited by Fusarium oxysporum f.sp. cepae

The study was undertaken to investigate the biocontrol potential of the native antagonists for the efficient usage of Pseudomonas fluorescens, Trichoderma viride and Glomus mosseae for the successful biological management of F. oxysporum f.sp. cepae causing basal rot of onion. In general all the native Trichoderma spp. tested significantly inhibited the mycelial growth of Fusarium oxysporum f.sp. cepae. However, among the isolates, the isolate Tv5` showed the maximum inhibition and significantly inhibited the growth of F. oxysporum f.sp. cepae (15.42 mm), which was 82.86 per cent reduction on the growth of the pathogen when compared to control. Among the Pseudomonas isolates, Pf2 produced significantly the minimum mycelial growth (23.32 mm) accounting for 80.82 per cent reduction on the mycelial growth of F. oxysporum f.sp. cepae over control. The results obtained on the efficacy of combined application of antagonists and G. mosseae, soil application with combination of T. viride (Tv5) and P. fluorescens (Pf2) plus soil application of G. mosseae treatment (T7) recorded the minimum wilt incidence (4.82 %). Similarly, the same treatment recorded the maximum growth parameters such as shoot length (35.42 cm), root length (5.0 cm) and bulbs (6.0). The control recorded the minimum growth parameters such as shoot length (18.62 cm), root length (2.5 cm) and number of bulbs per plant (1.0).