Biological Control of Groundnut Root Rot in Farmer’s Field

Groundnut is an important oilseed crop predominantly grown in Rajasthan, India and has suffered a 55 to 85 percent root rot disease caused by multiple pathogen complex mainly Aspergillus niger, Apergillus flavus, Sclerotium rolfsii, Thievaliopsis basicola, Rhizoctonia solani and Pythium aphanidermatum perennating in soil and seed. Trichoderma harzianum (Th3) was used against Groundnut varieties (GG-10, GG-20, M-13 and Local varieties) to reduce the yield loss by root rot disease during the year 2009 and 2010 in farmers’ fields in twelve villages in the Jaipur district of Rajasthan. The field trials were conducted by the application of Trichoderma harzianum in the form of powder and liquid bio-formulation. Trials were conducted by treating the soil, seed and foliage with powdered bio-formulation (Th3 SD, SA) at 5 g per kg seed/soil followed by spray treatment with liquid bio-formulation (Th3 FS) at 5 ml/l along with recommended IPM practices. The crops under farmer practice were significantly lower in yields with the diagnostic blackening symptoms travelling from roots to stem affecting the vascular system followed by shredding at root-stem internodes resulting in complete wilting and plant death while in Th3 treated crop blackening reduced and the root vascular system was free of disease. Maximum values of yield (39.17 Q/ha), R.C. Index (0.15), C.F.U. (38.5 x 106), and lowest root rot incidence (14.03%) was recorded in the Th3 treated groundnut crops. Increase in annual income also encouraged farmers to use the Trichoderma technology. Participatory approach and interaction between researcher and farmers helped in quick adoption and dissemination of use of biocontrol agents for groundnut growers in Rajasthan state, India.