Mungbean Yellow Mosaic Virus Vector

📖 Description

Mungbean Yellow Mosaic Virus Vector (Bemisia tabaci biotype Asia II-1), also called Mungbean Whitefly or Legume Whitefly, is the single most destructive insect pest of mungbean and urdbean across the Indian subcontinent, particularly severe in the major mungbean-growing belts of Rajasthan (Bikaner, Jodhpur, Nagaur, Jaisalmer — India’s largest mungbean-producing state), Maharashtra (Latur, Osmanabad, Aurangabad, Jalna), Karnataka (Gadag, Bagalkot, Vijayapura, Belgaum), Andhra Pradesh (Kurnool, Anantapur, Prakasam), Telangana (Mahabubnagar, Nalgonda, Adilabad), Tamil Nadu (Tirunelveli, Ramanathapuram, Sivaganga), Madhya Pradesh (Indore, Ujjain, Dewas), Uttar Pradesh (Agra, Mathura, Aligarh), Bihar (Muzaffarpur, East Champaran, Samastipur), Odisha (Cuttack, Puri, Khordha) and West Bengal (Purba Medinipur, Nadia, Murshidabad) where India is the world’s largest producer of mungbean (over 4 million hectares cultivated, producing over 2 million tonnes annually — mungbean (greengram) is a critical kharif pulse crop for India, providing the primary source of protein and iron for the Indian vegetarian diet, and India produces over 50% of the world’s mungbean). The pest is unusual among mungbean pests because (a) it is a specific biotype of Bemisia tabaci (Asia II-1, formerly called ‘mungbean specialist biotype’) that has evolved to preferentially colonise legumes and is the most efficient known vector of Mungbean Yellow Mosaic Virus (MYMV) — a devastating begomovirus that can cause 30-100% yield loss in susceptible varieties, (b) the direct feeding damage (sap sucking, honeydew, sooty mold) is minor compared to the indirect virus transmission damage — meaning that whitefly population management rather than direct damage control is the primary management goal, (c) the whitefly acquires MYMV in 15-30 minutes of feeding on an infected plant and can transmit it for life (persistent circulative transmission) — meaning that even a brief whitefly visit to an infected plant can lead to widespread virus transmission in the crop, (d) the pest is most severe during the critical first 30 days after sowing when plants are most susceptible to virus infection — even a brief whitefly outbreak during this period can devastate the crop with no curative treatment available once plants are infected, (e) the pest has a very short life cycle (18-25 days) allowing 12-15 overlapping generations per year and rapid population buildup, (f) the pest has a wide host range (legumes, cotton, tomato, cassava, weeds) allowing populations to persist between mungbean crops via weeds and other crops, and (g) the pest has developed resistance to most major insecticide classes (organophosphates, pyrethroids, neonicotinoids) in many parts of India due to indiscriminate use. IPM with MYMV-resistant mungbean varieties (Pusa Vishal, Pusa Ratna, IPM 02-3 — most critical preventive measure, virus cannot be cured once plant is infected), seed treatment with imidacloprid @ 5 g/kg (provides 30-45 days protection — covers the critical first 30 days when plants are most susceptible to virus infection), yellow sticky trap monitoring, biological control (conservation of native predators), neem-based sprays, need-based insecticide rotation (essential to slow resistance), roguing of virus-infected plants (single infected plant can be source for entire field outbreak within 7-14 days — most critical disease management practice), weed host management (Croton, Acalypha, Ageratum serve as virus reservoirs between seasons), and barrier cropping (maize, sorghum around field borders to intercept incoming whiteflies) provides effective and sustainable control. The pest is a particular concern for Indian mungbean growers because MYMV outbreaks can devastate entire crops with no curative treatment available once plants are infected — prevention through resistant varieties, seed treatment, and roguing is the only effective strategy. The pest is most severe in late kharif sowing (Jun-Jul) when whitefly populations peak and in continuous mungbean cropping. Climate change with warmer drier conditions is expanding the pest’s range and severity in northern India, with the virus now reported from regions previously too cool for significant whitefly populations.