Prevalence of Begomoviruses and their Molecular Detection in Major Solanaceous Crops of Eastern Bihar, India

Abstract

Begomovirus-induced leaf curl disease is a major constraint to the production of solanaceous crops in tropical and subtropical regions. These viruses are transmitted by whiteflies and can spread rapidly under favourable environmental conditions. During 2023-2025, systematic field surveys were conducted across ten major solanaceous crop-growing districts of eastern Bihar, namely Bhagalpur, Banka, Purnea, Katihar, Munger, Madhepura, Khagaria, Araria, Supaul and Kishanganj. The study aimed to assess leaf curl incidence, symptom variability, whitefly population and the associated begomovirus species in tomato, chilli and capsicum. At each location, approximately 18-20 symptomatic leaf samples were collected from the surveyed crops. Characteristic symptoms included leaf curling, cupping, stunting, mosaic, crinkling, puckering and blistering in interveinal areas. Disease incidence ranged from 5% to 18% across the surveyed solanaceous crops. Tomato showed the highest mean leaf curl incidence (17.28%), followed by chilli (15.89%) and capsicum (5.35%). The mean whitefly population recorded across locations and crops was 4.47 per plant. Polymerase chain reaction assays using universal and species-specific primers detected both mono- and bipartite begomoviruses in most tested DNA samples. Tomato leaf curl New Delhi virus was mainly associated with tomato crops, whereas Tomato leaf curl Joydebpur virus was commonly detected in chilli and capsicum. Other species, including Tomato leaf curl Karnataka virus, Tomato leaf curl Palampur virus, Tomato leaf curl Gujarat virus and Pepper leaf curl Bangladesh virus, were detected at low frequencies or in limited samples. The findings indicate the widespread occurrence and molecular diversity of begomoviruses infecting solanaceous crops in eastern Bihar. The results may support disease monitoring and the development of integrated management strategies, including vector management.