Survey, collection, isolation and pathogenicity test of Aspergillus niger van. Teighem causing collar rot of groundnut in Sikar and Jaipur district of Rajasthan

Groundnut (Arachis hypogaea L.) is an important oil seed crop. A large number of diseases play a major role in limiting the yield of groundnut. Among all the soil born diseases, collar rot caused by Aspergillus niger is very important. This disease is wide spread and causes serious losses. Comprehensive knowledge on incidence and severity of collar rot disease is essential in devising area-wise control measures to this hitherto difficult to manage disease. For that, a survey was conducted in groundnut growing areas of Sikar and Jaipur districts of Rajasthan during kharif season 2014–2015. The disease incidence in different Tahsil of Sikar and Jaipur district varied from (13.09 to 52.00%). The incidence was more in sandy soil (52.00%) followed by sandy loam (43.00%). The Percent Disease Incidence (PDI) showed that the soil inoculum caused maximum disease pressure compared to seed inoculum.