Tomato yellow leaf curl virus (Kokenae strain)

Pathogen and disease type: Begomovirus kokenae belongs to the Geminiviridae family, genus Begomovirus. It is a viral pathogen causing systemic damage to plant tissues. The virus carries a single-stranded DNA genome that hijacks host cell processes, leading to significant disruption of hormonal balance and photosynthetic activity.

Affected crops: This virus primarily infects Solanaceous plants, with a strong preference for tomatoes (Solanum lycopersicum). While commercial crops suffer the most, various wild weeds act as hosts, maintaining the viral presence in the environment throughout the year and serving as sources for new infections.

Symptoms and signs: The typical diagnostic features include chlorotic margins on leaves, upward curling of the leaflets, and stunted growth. Infected plants show shortened internodes and a bushy appearance. Fruit development is severely impacted, with flower abortion and poor fruit set leading to significant yield reduction.

Conditions for development and spread: The virus is transmitted in a persistent circulative manner by the whitefly vector, Bemisia tabaci. The prevalence of the disease is highly dependent on the population density of whiteflies. Warm and dry climates facilitate rapid reproduction of vectors, leading to swift transmission across greenhouses and open fields.

Harmfulness and protection measures: The economic impact is severe, often resulting in total crop failure in susceptible varieties. Key management practices include:

• Utilization of resistant or tolerant tomato hybrids.
• Rigorous monitoring and control of whitefly populations with systemic insecticides.
• Implementation of insect-proof nets in protected cultivation.
• Sanitation, including the removal of infected plants and surrounding weed hosts.