Associative effect of biofumigation and biocontrol agents in management of root knot nematode Meloidogyne hapla in Gerbera

Abstract: Protected cultivation is an emerging technology in Nilgiris for raising cut flower crops. Due to controlled environmental condition and continuous growing of crops, the root-knot nematode Meloidogyne hapla has emerged as a major problem in gerbera cultivation causing enormous yield loss. The damage progressively increases if proper sanitation control measures are not followed during the polyhouse cultivation. In the absence of Methyl Bromide, it is necessary to use other options. Biofumigation was evaluated to control soil borne nematode parasites with the aim to develop bio-pesticides, which could be effective against root knot nematodes without deteriorating soil environment. Two field trials were conducted to study the effect of combined use of biofumigants and bioagents on the nematode population. Mustard crop was ploughed in situ before flowering and covered with a plastic mulch for one month in polyhouses. The biocontrol agents viz., Pseudomonasfluorescens and Trichoderma viride were tried either alone or in combination with biofumigation. The stem length, flower yield and nematode population in soil were recorded. The study conducted at two different locations indicated that biofumigation with mustard followed by soil application of P. fluorescens @1.25 kg/ha at the time of planting significantly suppressed the population of M. hapla in soil by 67.5 to 67.8% and enhanced the flower yield of gerbera by 41 to 44%.