Occurrence and Symptomatology of Mungbean Yellow Mosaic Virus (MYMV) in Mungbean [Vigna radiata (L.) Wilczek] in South Gujarat

Mungbean [Vigna radiata (L.) Wilczek] is one of the important pulse crop, primarily grown for food in India. During the survey, occurrence of mungbean yellow mosaic virus (MYMV) in mungbean was noticed in serious proportion causing heavy losses in Navsari, Surat and Valsad district. Cultivar GM-4 and K-851 were found more severely affected at the flowering stage during summer season. Roving field surveys were under taken in and around Navsari, Surat and Valsad district, the total 16 location to find out occurrence of the mungbean yellow mosaic virus (MYMV) during the summer 2010 in the field. The MYMV incidence increased with increase in the crop stages. Crop at the first trifoliate leaf stage was 08-12 per cent, second trifoliate leaf stage was 16-20 per cent, before flowering stage were observed 41 to 55 per cent incidences and at the time of maturity stage showed 65-76 per cent incidence of MYMV. Fields of Sugarcane Research Station, N.A.U., Navsari farm were observed periodically. Three popular varieties of mungbean viz., K-851, GM-4, GM-3 verity were sown in the field. None of the variety showed resistance against the disease and 75 to 100 per cent incidence was observed at the time of maturity. Among these, K-851 showed cent per cent incidence of the MYMV. The disease appeared in the field as small scattered yellow to golden yellow colour flecks on the infected leaves. These were scattered on the entire leaves and were more concentrated near the leaf venation. The severity of the symptoms could be seen in the newly emerging leaves, where in case of high susceptibility cent per cent area of the leaf turned yellow. The symptoms could be observed on all the green colored aerial part of the plants including cotyledon leaf, trifoliate leaves, stem, petiole, flower part, pod and seeds. Infected plant remained stunted with few pods of small size and shriveled seed.