Survey and management of Pestalotiopsis leaf blight of Jatropha a destructive new disease in Karnataka.

摘要

Field studies were conducted in 2 agroclimatic zones in Karnataka, India (zone 3 and zone 8), in 2006, to determine the incidence and severity of Pestalotiopsis blight of Jatropha curcas. The incidence of Pestalotiopsis blight was observed in all the plantations and hedge grown jatropha with very high incidence and disease severity index (DSI) levels, irrespective of agroclimatic zones. For field level management experiments, a jatropha plantation in the Ranebennur taluk of the Haveri district, which recorded the highest incidence and severity in the disease survey, was selected. Based on in vitro evaluations, the best proven fungitoxicants in mycelial growth inhibitions were employed for field evaluations. The treatments comprised 0.1% of mancozeb, tridemorph and carbendazim, Trichoderma harzianum and Bacillus subtilis at 106 cfu/ml and 10% leaf extract of Lantana camara. In the field evaluations, 2 sprays of 0.1% mancozeb at 30-day intervals proved highly effective in suppressing the disease by showing very low DSI (1.17) even after 90 days of spraying compared to a DSI of 1.85 in the control, followed by B. subtilis.