Integrated foliar diseases management of legumes

Of the most important food legumes grown world over, chickpea (Cicer arietinum L.), lentil (Lens culinaris Medik.), faba bean (Vicia faba L.), grasspea (Lathyrus sativus L.) and field pea (Pisum sativum L.) are grown in cool season, while pigeonpea (Cajanus cajan (L.) Millsp.), blackgram (Vigna mungo (L.) Hepper), mungbean (V. radiata (L.) Wilczek), horsegram (Macrotyloma uniflorum (Lam.) Verdc.), cowpea (V. unguiculata (L.) Walp) and soybean (Glycine max (L.) Merr) are known as warm season legumes. Biotic stresses such as diseases, insect-pests, nematodes and weeds substantially reduce the yield of these legumes in farmers’ fields. Among these, fungi and viruses are the largest and most important groups affecting all parts of the plant at all stages of growth of both cool season and warm season food legumes. According to estimates made in India nearly 10-15% of food legumes production is lost due to diseases alone. Among Integrated foliar diseases management of legumes 144 fungi, diseases caused by species of Botrytis and Ascochyta are of great importance to faba bean, lentil, chickpea and field pea. The genus Stemphylium causes foliar disease in lentil and chickpea and Septoria species causes leaf spots in cowpea. The viruses of major economic importance on cool season legumes belong to the Luteoviruses, Nanoviruses, Potyviruses, Carlaviruses, Furoviruses. Perusal of the literature on diseases of food legumes and their management reveals new records of diseases, loss estimations, biology of causal agents, identification of host plant resistance and fungicide use. The purpose of this paper is to review the etiology and biology of major foliar diseases of food legumes and outline current and suggested future research on issues related to disease management strategies globally. Integrated disease management (IDM) modules for important foliar and viral diseases of chickpea (ascochyta blight and botrytis gray mold), pigeonpea (sterility mosaic and Phytophthora blight), lentil (rust, ascochyta blight and stemphylium blight), faba bean (ascochyta blight, chocolate leaf spot and rust), field pea (powdery mildew and Ascochyta complex), mungbean and urdbean (viral diseases and chocolate leaf spot) and cowpea (viral diseases and chocolate leaf spot) are discussed. The IDM involves the individual component of disease management such as host plant resistance (HPR), agronomic practices, judicious use of fungicides, pesticides for vector control, biopesticides for pathogen control, risk forecasting that operate on different aspects of the disease etiology, such that they complement each other and can be applied together in farmers’ fields collectively to provide farmers with maximum economic return.