The article focuses on a study related to assessment of the extent of occurrence of mungbean yellow mosaic virus (MYMV) disease of French bean in different agro-climatic zones of Karnataka, India. Topics include significant difference disease incidence of MYMV during 2014-15, variation in disease incidence due to factors such as relative humidity and difference in temperature; and crop infected at early showing more severe symptoms with leaves exhibiting mosaic and reduction in leaf size.