Tomato Leaf Curl Virus (TYLCV)

The Tomato Leaf Curl Virus (TYLCV) infects tomato plants, and sometimes other hosts in the Solanaceace family (nightshade and jimsonweed). Symptoms include small leaves that curl upward, crumpling, and yellowing on the margins and veins. Flowers fall off the plant, reducing the crop. The plants themselves look stunted—due to shortened internodes—giving the plant a bushy appearance. Other hosts may exhibit minimal symptoms, or no symptoms.

According to the Tomato Yellow Leaf Curl brochure, published by the University of California Agriculture and Natural Resources Statewide IPM Program, the disease was first observed in Israel in the 1940s; spread to the Caribbean islands and southeastern United States in the 1990s; moved to northern Mexico, Texas, and Arizona in the 2005-2006; and was found in a greenhouse in Imperial County in 2007. The disease thrives in tropical and subtropical environments, and in Mediterranean climates.

Upward leaf curling and reduction in internode length in tomato infected with TYLCV.
Copyright, ASPnet

Bemisia whiteflies and some leafhoppers are the main vectors for the disease. After feeding on an infected plant, the insect is infected for its lifetime and spreads the virus by feeding on uninfected plants. When tomato plant hosts are not available, it is thought that the virus can exist in weed hosts. The virus is not transmitted in seeds or mechanically (by touch), but can be transmitted if infected plants are transported to uninfected areas. If the virus spreads to California, it could have a significant negative impact for commercial tomato growers, and for backyard tomato enthusiast

For management tips, see the Integrated Pest Management (IPM) site. In general, recommendations include planting TYLCV-resistant varieties, maintaining “tomato-free” periods when there is no host, eliminating weeds that could be hosts during tomato-free periods, removing diseased plants, avoiding transport of infected plants to uninfected areas, and managing whiteflies. TYLCV symptoms resemble symptoms for other diseases, but accurate tests are available to identify the virus.