Investigation of disease occurrence and pathogenicity test of Aspergillus niger causing collar rot of groundnut in Rajasthan

Abstract

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 an important pathogen. This disease is wide spread and causes serious losses. So, a survey was conducted in groundnut growing areas of Sikar and Jaipur districts of Rajasthan during kharif season 2014-2015. 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. Samples were collected from different fields for isolation of pathogen and further studies conducted. The disease incidence in different Tahsil of Sikar and Jaipur district varied from (13.09 to 52.00%). The incidence of collar rot was more in sandy soil (52.00%) followed by sandy loam (43.00%). Pathogenicity test were proved by using Kotch’s Postulate. Further, the seed inoculum and soil inoculum levels were tested for disease pressure on groundnut plant. The Percent Disease Incidence (PDI) showed that the soil inoculum caused maximum disease pressure compare to seed inoculum.