Induced Systemic Resistance and Evaluation of Bio-control Agents for Management of Pigeonpea Wilt Caused by Fusarium udum

The performance of the four fungal and two bacterial bioagents were evaluated for the bicontrol efficacy and ability to induce systemic resistance against Fusarium udum causing wilt of pigeonpea which is posing a serious threat to pigeonpea growing regions of India. Among the six isolates, maximum mycelial inhibition was noticed in Trichoderma harzianum (Th- R) as compared to other biocontrol agents. Among contact fungicides, maximum inhibition (> 75 %) of mycelium was recorded in Mancozeb and capton at 0.20 and 0.3 % concentrations. More than 90% inhibition was recorded among the systemic fungicides at all the all the concentrations except thiophanate methyl which recorded 53.67 % inhibition at 0.05 % concentration. Among different treatment combinations of biocontrol agents, the highest vigour index was recorded in P. fluorescense (RP- 46) + P. putida (RP- 56) treated seeds in both the cultivars (Moderately resistant and susceptible). The level of expression of defense related enzymes (PO, PPO & PAL) was more in moderately resistant cultivar(BSMR- 736) rather than susceptible one(ICP- 2376). In glass house experiment seeds treated with P. flourescens (RP- 46) + P. putida (RP-56) recorded least wilt incidence as compared to other treatments. In both Kharif seasons of 2013/14 and 2014/15 recorded significantly lowest wilt incidence and highest yield in soil drenching with 0.2 % Carbendazim fungicide. Among the biocontrol agents, seed treatment @4 g / kg seeds + soil application of PGPR (P. flourescens & P. putida) consortium @ 25kg/ ha in FYM @ 50 kg/ ha, recorded least wilt incidence and highest yield.