Roguing for Control of Peanut Bud Necrosis Virus Disease in Tomato in India

Bud necrosis disease caused by Peanut bud necrosis virus (genus Tospovirus, family Bunyaviridae) is a major constraint to tomato production in India. The disease affects fruit yield and quality leading to reduced income to farmers and non-availability of quality tomatoes for consumers. PBNV is transmitted by Thrips palmi. Both have a broad host-range including legume and solanaceous crops and non-crop species and can survive throughout the year, thereby posing risk to tomato crops. Controlling bud necrosis disease has met with several challenges including poor efficacy of chemical control of thrips vector, overlapping cultivation of susceptible crops, year-round presence of reservoir hosts for the virus and vector, and the lack of sources of resistance in tomato germplasm. Monitoring nurseries producing tomato seedlings and mapping spatio-temporal distribution of PBNV-infected tomato plants in farmers’ fields indicated that infected transplants from nurseries could serve as a primary source of inoculum for field spread of the disease. Multilocation field trials demonstrated that removing virus-infected tomato seedlings during transplanting and rouging of infected transplant escapes within 45 days of post-transplanting could minimize spread of the disease. An analysis of benefit-cost ratio showed advantages of roguing as a simple but robust tactic to reduce yield loses. By adopting rouging, farmers were able to avoid pesticide applications thereby incurring no extra costs for controlling thrips vectors. Roguing in combination with other IPM strategies are being deployed as an alternative to pesticide-based tactics for mitigating negative impacts of PBNV to tomato production in smallholder agriculture.