Vol. 12, Issue 3 (2023)

Author(s):
K Jyothirmai Madhavi, Prasada Rao RDVJ, Subbarao M and Lal Ahamed M

Abstract:
Surveys for occurrence of necrosis disease caused by PBNV and/or TSV were undertaken during rabi 2007-08, summer 2008 and kharif 2008 in major blackgram and greengram growing areas of Andhra Pradesh. In 2008 kharif season, the village wise mean incidence of necrosis disease ranged from 51.03-78.32 per cent incidence in Medak district followed by Guntur (1.68-3.63%) and Krishna (0-1.03%) in blackgram while it ranged from 2.85- 4.94% in Medak district followed by Guntur (1.19-2.77%) and Nalgonda (0-0.27%) in greengram. In 2007-08 Rabi the disease incidence ranged from 6.15 to 10.12% and 0.90-2.13% in Medak district in blackgram and greengram, respectively. Srikakulam district ranged from 28.96-42.55% disease incidence in summer 2008 in greengram. Krishna and Nalgonda districts showed negligible or no disease incidence. Necrosis/leaf curl disease in blackgram and greengram was manifested with similar symptoms such as veinal chlorosis associated leaf curl. These veins later turned to necrotic resulting in downward curling of leaves where necrotic veins were clearly observed on the under surface of the leaf, occasionally, chlorotic spots turning to necrotic, leaf necrosis leading to death of growing bud. Early infection caused death of the plant. PBNV appeared to be more prevalent than TSV in blackgram and greengram in DAC-ELISA tests where PBNV was 95.12% and 89.47% (NBPGR-RS, Hyderabad fields) and TSV was 7.31% (NBPGR-RS, Hyderabad fields) and 7.89% (Jogipet mandal of Medak district) in blackgram and greengram, respectively while mixed infections also were recorded.