Use of Neem leaves as soil amendment for the control of collar rot disease of chickpea

Abstract

AbstractChickpea (Cicer arietinum L.) is an important grain legume that is attacked by the fungal pathogen, Sclerotium rolfsii, responsible for collar rot disease. In the present study, the pathogen was isolated from diseased chickpea seedlings and identified on molecular basis using internal transcribed spacer (ITS) and β-tubulin markers. To control this pathogen, an in vivo study was carried out, using Neem (Azadirachta indica A. Juss.) leaf dry biomass (1, 2, and 3%) as soil amendment. A broad-spectrum fungicide mancozeb was selected as a reference and the data regarding plant growth and mortality rates were calculated. In positive control, the highest seedling mortality (56%) was recorded in comparison to negative control (0%) after 30 days of sowing. In 1, 2, and 3% concentrations of A. indica dry leaf biomass, the seedling mortalities were 49, 38, and 38%, respectively. On the other hand, the mancozeb-treated seedlings showed the lowest plant mortality rate (28%). Soil treatments with mancozeb as well as with 1 and 2% leaf biomass concentrations showed marked differences in root and shoot dry biomasses over positive control. In a laboratory bioassay, methanolic leaf extract of Neem of 0.5 to 3.5% concentrations reduced biomass of S. rolfsii by 86–90% over control. The present study concluded that 2% A. indica leaf amendment was the most useful concentration for management of collar rot disease of chickpea.