Biological Control of Onion Basal Rot Disease : Evaluation of biocontrol agents and organic amendments against onion basal rot caused by Fusarium oxysporum f.sp.cepae

Efficacy of various biocontrol agents and soil organic amendments were evaluated for their potential to manage the basal rot of onion caused by Fusarium oxysporum.f.sp.cepae. Trichoderma viride, Trichoderma harzianum and Pseudomonas sp. were collected from different onion growing areas of Tamil Nadu and they were tested for their antagonistic activity against Fusarium oxysporum.f.sp.cepae by dual culture technique. Among the tested isolates of Trichoderma sp., T. harzianum (TH3) recorded the maximum (82.77%) inhibition. Among the sixty two isolates of Pseudomonas sp. Pf 12 significantly exerted highest (74.68) per cent reduction of mycelial growth of Fusarium oxysporum.f.sp.cepae. Among the different organic amendments, mahua cake (10%) significantly recorded maximum 61.00 per cent reduction of mycelial growth over control. Consortial formulation of Pf 12 + Pf 27 + TH3 recorded the least disease incidence of basal rot under glass house condition