Tomato yellow leaf curl virus (TYLCV) is a plant virus classified within the Begomovirus genus and Geminiviridae family. This DNA virus primarily targets tomato plants, causing substantial crop losses for growers worldwide, particularly in tropical and subtropical regions. Its rapid global spread over recent decades has made it a major agricultural concern.
Recognizing TYLCV in Your Plants
TYLCV infection in tomato plants causes several distinct visual symptoms. The most characteristic signs include an upward curling of the leaves, often accompanied by interveinal and marginal yellowing. Affected leaves may also appear crumpled or reduced in size.
Infected plants exhibit stunted growth, with shortened internodes that can give the plant a bushy or “bonsai”-like appearance. Flower drop is common, leading to a significant reduction in fruit set and overall yield. Symptom severity can vary depending on the plant’s age at infection and environmental conditions. Young plants infected early often show the most severe stunting and may produce no fruit.
How TYLCV Spreads
The silverleaf whitefly, Bemisia tabaci, is the primary vector for TYLCV transmission. Whiteflies acquire the virus when feeding on infected tomato plants. Once acquired, the virus persists within the whitefly’s body without replicating, moving through its digestive system, hemolymph, and salivary glands.
After acquiring the virus, a whitefly can remain infectious for the remainder of its lifespan, transmitting the virus to healthy plants as it feeds. The virus can be efficiently transmitted by adult whiteflies, with an acquisition access period as short as 15–20 minutes and a latent period of 8–24 hours before the insect can transmit the virus. While whiteflies are the dominant factor, TYLCV can also spread long distances through the movement of infected symptomless plants, such as tomato transplants, which may carry the virus for up to three weeks before symptoms appear.
Strategies for Managing TYLCV
Managing TYLCV involves a multifaceted approach combining prevention and control measures. An effective strategy is planting tomato varieties bred for TYLCV resistance. Many commercially available resistant cultivars, such as Shanty, Security, Tygress, and Inbar, are now available, offering reduced reliance on pesticides and improved yield stability in areas prone to the virus. These resistant varieties may still accumulate the virus but typically exhibit mild or no symptoms, leading to better yields compared to susceptible plants.
Controlling whitefly populations is another important component of TYLCV management. Growers can deploy reflective mulches to deter whiteflies and reduce virus spread. Yellow sticky traps are also useful for monitoring and reducing whitefly numbers. For direct intervention, insecticidal soaps or biological control agents, such as predatory insects, can manage whitefly populations.
Good cultural practices also play a significant role in limiting TYLCV spread. Prompt removal and destruction of infected plants prevents further spread within a crop. Controlling weeds in and around planting areas is important, as some can serve as alternative hosts for whiteflies. Proper plant spacing improves air circulation and discourages whitefly infestations, while general sanitation helps maintain a healthy growing environment. Small-scale growers can protect their plants using physical barriers like row covers or fine-mesh screens to exclude whiteflies, particularly during high activity.