Biointensive management of wilt disease of lentil through biocontrol agents and organic amendments

Abstract

Lentil (Lens culinaris M.) is an important dietary source of protein and other essential nutrients in South and West Asia, North and East Africa. Lentil crops are susceptible to a number of diseases caused by fungi and other parasites. Among them, the most significant and serious soil-borne disease is Fusarium wilt (Fusarium oxysporum f.sp. lentis: Fol). Systematic studies in laboratory, cage house and field trials were conducted (2016-17 to 2017-18). Laboratory experiments were carried out in completely randomized design with four replications and field trials were carried out consecutively during 2016-17 and 2017-2018 crop season in Randomized Block Design (RBD) with four replications using L9-12, a susceptible cultivar. Under in vitro, bio efficacy of selected bio agents, maximum 81.33 per cent mycelial growth inhibition of pathogen was recorded in Trichoderma harzianum (local isolate) and minimum mycelial growth inhibition 55.00 per cent was recorded in Bacillus subtilis. Under in vivo condition, effect of selected bio agents and organic amendments on disease incidence, percent disease control, pathogen spore in per gram soil and yield ha^-1 of lentil was recorded. Application of Trichoderma harzianum (Local isolate) @ 6g/Kg seed was found most effective with maximum seed germination 91.95 and 90.62 per cent, lowest disease incidence of 24.22 and 25.39 per cent and higher pooled mean grain yield 774.31 kg/ha over check during 2016-17 and 2017-18, respectively. Among organic amendments, maximum disease control (42.02 per cent), minimum average disease incidence (36.33 per cent) and minimum pathogen spores (1.3x10⁴ per gram soil) were observed in neem cake amendment followed by poultry manure and vermicompost amendments. This indicates that these treatments can be effectively used for controlling Fusarium wilt disease under organic mode of lentil cultivation in Rajasthan.