Management of Collar rot of Groundnut with Bio-agent, Botanicals and Chemicals

摘要

Efficacy of pesticides was tested in vitro for the per cent mycelial growth inhibition of A. niger. Propiconazole, carbendazim and carboxin completely inhibited the mycelial growth up to 100 per cent at 200, 500 and 1000 ppm concentration, respectively as comparable with 86.94, 88.05 and 59.96 per cent at their respective 100, 200 and 500 ppm. Captan and thiram were found very less effective as they inhibited 81.11 and 72.77 per cent of fungal growth, respectively at higher concentration of 1000 ppm. Fungicide hexaconazole, herbicide pendimethalin and insecticide chlorpyriphos failed to show antifungal activity against A. niger even at 1000 ppm concentration. Three bio-agents viz., Trichoderma viride, T. harzianum and Pseudomonas fluroscence were tested for their inhibition of mycelial growth of A. niger in vitro. T. viride inhibited the mycelial growth up to 78.32 per cent followed by T. harzianum (72.50%), while the bacterial agent P. fluroscence only managed to inhibit 23.80 per cent of mycelial growth. Seed treatments with fungicides and soil inoculation with bio-agents significantly reduced the disease incidence. Among the botanicals, neem cake powder @ 20g/kg soil significantly controlled the disease up to 32.53 per cent.