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

Chickpea ( 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.