Current Knowledge on Pathogenicity and Management of Stemphylium botryosum in Lentils (Lens culinaris ssp. culinaris Medik)

Stemphylium blight (SB) caused by Ascomycete, Stemphylium botryosum Wallr. has been a serious threat to lentil cultivation, mainly in Bangladesh, Nepal, India, and Canada since its first outbreak in Bangladesh in 1986. The genus Stemphylium Wallr., a dematiaceous hyphomycete, comprises up to 150 species, and is pathogenic on a wide range of plants infecting leguminous as well as nonleguminous crops. In recent years, studies indicated overlapping in morphological characters among the different species under the genus Stemphylium, making the identification and description of species difficult. This necessitates different molecular phylogenetic analysis in species delimitation. Therefore, a detailed understanding of spatial diversity and population structure of the pathogen is pertinent for producing source material for resistance breeding. The role of different weather variables as predisposing factors for the rapid spread of the pathogen necessitates devising a disease predictive model for the judicial application of fungicides. A dearth of information regarding spore biology, epidemiology, race diversity, host-pathogen interaction, and holistic disease management approach necessitates immediate attention towards more intensive research efforts. This is the first comprehensive review on the current state of knowledge and research efforts being made for a better understanding of the SB resistance through cognizing biology, ecology, and epidemiology of S. botryosum and effective disease management strategies to prevent widespread outbreaks of SB. The information regarding the biology and epidemiology of S. botryosum is also crucial for strengthening the "Integrated Disease Management" (IDM) programme. The need for a regional research network is advocated where the disease is becoming endemic.