Quantification of Green Fodder Yield Losses Due to Diseases and Insect-pests Infecting Cowpea in North-Eastern and North-Western Regions of India

Background: Cowpea [Vigna unguiculata (L.) Walp.] is a leguminous crop cultivated for pulse, feed and fodder in tropical and sub-tropical regions worldwide. Although the cowpea is adapted to most of the regions in India, the crop is threatened by diseases like root rot, cowpea yellow mosaic virus, leaf spot and anthracnose and pests such as aphids and defoliators. Methods: In this study, green fodder yield losses due to diseases and pests were quantified in fodder cowpea at five locations for three cropping seasons 2019-2021. There were two treatments one was protected with fungicides/biocontrol agents/biopesticides and another was unprotected. The incidence of diseases and pests was recorded in both treatments. Result: The mean root rot incidence was 1.39 to 50.24 per cent at three locations, the severity of cowpea yellow mosaic virus ranged between 0.69 to 14.49% and the disease severity of foliar diseases was 0.75 to 40.40 per cent. Whereas aphid population was in the range of 3.93 to 30.26 aphids per twig and infestation on cowpea by defoliators was observed in the range of 1.31 to 45.64 per cent. The average green fodder yield losses were ranged between 11.06 to 46.21 percent with highest losses were recorded at Palampur location and lowest were estimated at Ludhiana location. The crop loss models were also prepared for disease and pest damage to assess the relationship between disease severity, pest infestation and green fodder yield of cowpea. The correlation was found negative/positive and highly significant at p=0.01 and p=0.05 between disease severity, pest damage values and green fodder yield losses at all five test locations. Regarding the management of diseases and pests, the focus should be on the timely application of management measures.