Tomato Yellow Leaf Curl Virus

Infected tomato plants show leaves that curl upward and inward, become cupped, and turn yellow between the veins, especially at the growing tips. Plants infected when young are severely stunted with a bushy appearance and drop many flowers, resulting in little or no fruit. Plants infected later tend to show milder symptoms and less yield loss because much of the crop is already set.

Tomato yellow leaf curl virus is transmitted by the whitefly Bemisia tabaci. Whiteflies acquire the virus while feeding on infected plants and can then transmit it to healthy plants, retaining the ability to infect for an extended period. The virus does not spread by simple contact or on tools, but it moves readily on infected transplants and through populations of viruliferous whiteflies moving between crops and weed hosts.

• Whiteflies acquire the virus from infected plants and transmit it while feeding
• Infected transplants can introduce the virus into a new planting
• Weed and volunteer hosts act as reservoirs between tomato crops
• High whitefly populations drive rapid spread within and between fields

Tomato is the principal crop affected, with common bean and various other cultivated and weed plants also able to host the virus or related begomoviruses. The disease is favoured by high populations of the whitefly vector, warm conditions that support whitefly activity, and continuous or overlapping tomato cropping that maintains virus reservoirs.

• High whitefly populations and warm conditions that favour the vector
• Use of infected transplants or nearby infected crops
• Weed and volunteer hosts that reservoir the virus
• Continuous or overlapping tomato production that sustains the cycle

Because the virus is spread by whiteflies and on transplants, management combines resistant varieties, clean planting material, and whitefly management, with special emphasis on protecting young plants during the most vulnerable early growth stages.

• Grow resistant or tolerant tomato varieties where available
• Use clean, virus-free transplants raised under protection from whiteflies
• Manage whitefly populations and remove weed and volunteer reservoirs
• Protect young plants, which are most vulnerable to severe infection
• Consider crop-free periods and area-wide coordination where feasible