Tomato leaf curl Karnataka-2 virus

Pathogen and disease type: This agent belongs to the genus Begomovirus within the Geminiviridae family. It is a viral pathogen with a single-stranded DNA genome. It causes systemic infections that alter the physiological processes of the host plant, leading to significant physiological stress and severe developmental abnormalities.

Susceptible crops: The virus primarily targets tomato plants (Solanum lycopersicum). However, it has a broader host range including other solanaceous crops like peppers and eggplants. Various wild weeds found near agricultural fields act as secondary hosts, facilitating the virus's persistence throughout the year.

Symptoms and signs: Infected plants exhibit severe leaf curling, yellowing, and puckering. The leaves may become small and brittle. The plants often appear stunted, with shortened internodes. Fruit production is drastically affected, resulting in smaller, misshapen, and commercially valueless produce.

Development and impact: The virus is transmitted in a persistent manner by the whitefly Bemisia tabaci. The spread is highly dependent on environmental factors that favor whitefly population explosions, such as warm temperatures and high humidity. The economic impact is severe, as early-stage infection can lead to total crop failure, rendering the plant production unproductive.

Prevention and control: Management focuses on controlling the whitefly vector through integrated pest management (IPM) practices, including the use of insecticides and biological controls. Cultural practices are equally important, such as planting resistant cultivars, using physical barriers like insect-proof screens in greenhouses, and maintaining clean fields free of alternative weed hosts.