Bio-Management of Fusarium Wilt Disease Complex with Pseudomonas fluorescens and Aspergillus niger

Abstract

Flue Cured Virginia (FCV) tobacco is a major rain-fed crop grown in light soil regions of Karnataka. Fusarium wilt disease complex caused by Fusarium oxysporum f. sp. nicotianae in association with Root-knot nematodes, Meloidogyne incognita is a major threat to the successful production and also for its sustainability in the region. The tobacco crop affected with above malady exhibit stunted growth, severe wilt symptoms, drying of leaves on one side of the plant and with conspicuous galls on the infected roots resulted in heavy yield and quality loss. Fungicides and nematicides are being used against this wilt disease complex with limited efficacy. Extensive use of pesticides of chemical origin especially in higher doses for disaese control has to be avoided due to higher costs and associated hazards to the environment. Replicated trials were conducted with antagonistic bacterium, Pseudomonas fluorescens and antagonistic fungi, Aspergillus niger singly and in combinations against fusarium wilt disease complex in FCV tobacco under sick field conditions. Results revealed that application of P. fluorescens @ 1g/plant in combination with A. niger enriched with FYM @ 100 g /plant at the time of planting resulted in 61.0% reduction in fusarium wilt disease incidence at 70 DAT compared to untreated check. There was significant reduction in root knot nematode incidence in terms of RKI (Root- Knot Index) to 1.93 and final soil nematode population to 72.5 as compared to RKI of 3.71 and final soil nematode population of 140 in untreated check. Subsequent increase in total cured leaf and bright grade yield was 1311 kg/ha and 926 kg/ha respectively as compared to 1042 kg/ha and 615 kg/ha respectively in untreated check.