Skip to content

Yellow mosaic virus (MYMV/MYMIV) of urad and moong

Yellow mosaic disease (YMD) of mungbean (greengram, Vigna radiata) and urdbean (blackgram, Vigna mungo) is caused by two whitefly-transmitted begomoviruses — Mungbean Yellow Mosaic Virus (MYMV) in peninsular India and Mungbean Yellow Mosaic India Virus (MYMIV) in northern and central India. ICAR-IIPR Kanpur and ICAR-NBPGR estimate annual yield losses of 30-90% in susceptible cultivars during the kharif and spring/summer seasons, making YMD the single most damaging biotic constraint on summer moong and kharif urad in India.

Pathogen and identification

MYMV/MYMIV are bipartite begomoviruses (genus Begomovirus, family Geminiviridae) with two single-stranded DNA components, transmitted persistently and exclusively by the whitefly Bemisia tabaci (Asia I and Asia II cryptic species). Diagnostic field symptoms:

  • Initial yellow specks on young trifoliate leaves at 3-4 weeks after sowing
  • Bright golden-yellow mosaic spreading from veins outward, often covering 50-100% of the leaf surface
  • Leaf puckering, downward cupping and reduced leaf size on later-formed trifoliates
  • Stunting, shortened internodes, delayed flowering
  • Pod malformation — pods small, distorted, with shrunken seed and reduced 100-seed weight (40-60% reduction)

Confirmation in lab uses PCR with begomovirus-specific primers and ELISA at NBPGR / ICAR-IIPR facilities.

Hosts and lifecycle

MYMV/MYMIV infect mungbean, urdbean, soybean, French bean, cowpea, mothbean and several weeds (Cleome viscosa, Croton bonplandianum). The virus does not survive in soil or seed; over-summering happens on weed reservoirs and on rabi pulses and soybean. B. tabaci acquires the virus in 15-30 min feeding on an infected plant, retains it for life and transmits in 15-30 min on a healthy plant. Whitefly populations build under hot dry weather (28-35 deg C, low rainfall), making summer moong and late-sown kharif urad especially vulnerable.

Damage and economic impact

Susceptible cultivars in MP, UP, Punjab, Haryana, Rajasthan, Maharashtra, Karnataka and AP commonly lose 30-60% yield, rising to 80-90% in epidemic years. Plants infected before flowering produce almost no harvestable grain. Urad in north India (Sonipat, Hisar) and moong in summer in Punjab/Haryana are the hot-spots; secondary spread can be field-wide within 10-14 days of first whitefly arrival.

Management

  • Resistant varieties (primary tactic): for blackgram — PU-31, Mash 391, Mash 414, IPU 2-43, KU 96-3, Pant U-31, NDU-99-1, Uttara, T9; for greengram — Samrat (IPM 2-3), Virat (IPM 2-14), Shikha (IPM 5-10), HUM-1, IPM 02-3, ML 818, SML 668, MH 421
  • Healthy seed: certified seed from disease-free locations; rogue early-infected plants by 30 DAS
  • Sowing window: avoid late kharif sowing (after 15 July); for summer moong, complete sowing by 5 April to escape peak whitefly populations
  • Cultural: maize or sorghum border rows of 3-4 lines act as whitefly barrier; remove parthenium and Cleome weed reservoirs; avoid moong-urad continuous cropping
  • Yellow sticky traps: 20-25 per hectare to monitor whitefly arrival; spray when whitefly counts cross 3-5 per plant
  • Insecticidal control of the vector: imidacloprid 70 WS seed treatment at 5 g/kg gives 3-4 week protection; foliar imidacloprid 17.8 SL at 100 ml/ha, thiamethoxam 25 WG at 100 g/ha, or diafenthiuron 50 WP at 600 g/ha at 25 and 40 DAS; rotate molecules to delay resistance
  • Avoid pyrethroids which flare whitefly populations

The ICAR-IIPR recommended package combines a resistant variety, seed treatment, early sowing, weed cleaning and need-based whitefly sprays.

See also: Blackgram crop, Greengram crop, PU-31 blackgram, Summer moong cultivation, NFSM-Pulses overview.

Sources

  1. Yellow Mosaic Disease management. ICAR-Indian Institute of Pulses Research, Kanpur.
  2. MYMV/MYMIV in pulses — review. ICAR-National Bureau of Plant Genetic Resources, New Delhi.
  3. Bemisia tabaci factsheet. CABI Plantwise.