Efficacy of fungicides and biocontrol agents against Pythium aphanidermatum causes damping off disease in ashwagandha (Withania somnifera L. Dunal)

摘要

Damping off is one of the most common disease under moist and cool atmosphere in ashwagandha (Withania somnifera) and other nurseries raising seedlings of solanacious crops. In W. somnifera, damping off disease incidence was recorded about 15-20% at the seedling stage during the rabi season of 2016 and 2017 in experimental fields, which is of great concern. In the present study, we investigated about the associated pathogen of damping off disease and evaluated various management strategies included seed dressing with chemicals, biocontrol agents and their different combinations. The causal agent of damping off disease on W somnifera was identified based on the morphological characteristics as Pythium aphanidermatum. Eight fungicides tested under invitro condition, metalaxyl-M (apron XL) showed the highest efficacy to inhibit the mycelium growth of P. aphanidermatum on PDA. In field condition, germination was significantly higher in seeds, treated with gibberellic acid @ 600 mg L~(-1). Seed treatment using metalaxyl M (1 ml/kg) along with Trichoderma viride (10 gm/kg) and furrow application of well decomposed FYM (1 kg/m~2) enriched with T. viride talc based formulation at 2.0% significantly reduced the seedling mortality caused by damping off disease in W somnifera.