Tomato yellow leaf curl

Tomato yellow leaf curl virus (TYLCV) is a destructive plant disease caused by a geminivirus of the genus Begomovirus. It is recognized globally as one of the most significant limiting factors in tomato production. The virus disrupts the vascular system and hormonal balance of the plant, leading to stunted growth, reduced fruit set, and severe chlorosis symptoms.

The primary vector for the transmission of TYLCV is the sweetpotato whitefly (Bemisia tabaci). The virus is acquired by the insect while feeding on infected plant sap and is then transmitted to healthy hosts in a persistent, circulative manner. It is important to note that the virus is not mechanically transmitted through seeds or contaminated soil, focusing management efforts exclusively on controlling the vector populations.

Typical symptoms include the upward curling of leaflets, yellowing (chlorosis) of the leaf margins, and a reduction in leaf size. Infected plants exhibit shortened internodes, giving them a bushy appearance. If the infection occurs at an early stage of growth, the plant may remain severely stunted, and flower buds may drop before setting fruit, leading to significant yield losses.

Disease progression is highly correlated with the presence and density of the whitefly population, which thrives under warm, dry environmental conditions. Weeds act as crucial viral reservoirs throughout the year, sustaining the virus when tomato crops are not present. Consequently, the presence of these alternate hosts during the off-season significantly increases the risk of infection in subsequent plantings.

Managing TYLCV requires a strict integrated pest management (IPM) strategy focused on preventing whitefly entry and colonization. Recommended practices include:

• planting TYLCV-resistant or tolerant tomato hybrids;
• utilizing insect-proof screening for greenhouse production;
• monitoring whitefly populations using yellow sticky traps;
• applying systemic insecticides at the seedling stage;
• eliminating weed hosts and practicing crop rotation to break the virus cycle.