Lettuce chlorosis crinivirus

Crinivirus lactucaflavi is a plant pathogen belonging to the genus Crinivirus. This virus targets the vascular tissues of its hosts, causing systemic infection that restricts nutrient transport and interferes with the plant's metabolic processes. It represents a significant challenge for greenhouse producers due to the rapid spread within confined environments.

The primary host for this virus is lettuce (Lactuca sativa). As a specialized pathogen, it thrives in environments where host plants are grown in high density. The virus typically colonizes the phloem, causing physiological changes that severely affect the quality and weight of the harvest, making infected crops unsuitable for commercial distribution.

Clinical signs of infection include striking interveinal chlorosis, which often starts on older leaves and spreads to the younger foliage. Infected plants exhibit stunted growth, reduced leaf size, and occasionally leaf brittleness or curling. Because these symptoms resemble nutritional deficiencies, farmers must often rely on molecular testing to confirm the presence of the virus.

The transmission of the virus is exclusively mediated by whiteflies (Aleyrodidae). The virus is transmitted in a semi-persistent manner, which means that the vector can acquire and transmit the virus after short feeding periods on infected host plants. Warm temperatures and high humidity in greenhouses significantly enhance the efficiency of virus transmission by increasing whitefly populations.

Effective management requires an integrated approach. Prevention strategies focus on

• Rigorous exclusion of whiteflies using greenhouse screens.
• Sanitation practices to remove potential weed reservoirs of the virus.
• Early detection using sticky cards for monitoring vector populations.
• Biological control through the release of natural enemies like Encarsia formosa.