Tomato chlorotic spot virus (TCSV) was found for the first time in Florida in field grown tomato plants in Dade and Hendry Counties this past spring. Early symptoms of infection are difficult to diagnose. In young infected plants, the characteristic symptoms consist of inward cupping of leaves and leaves that develop a bronze cast followed by dark necrotic spots.
Tomato chlorotic spot virus causes necrosis in tomato leaves and stems and causes ringspots and other deformations of the fruit. The symptoms are nearly identical to those of groundnut ringspot virus and laboratory diagnosis is necessary to distinguish one from the other.
Survival And Spread
Relatively few studies have been conducted on TCSV compared to other tospoviruses. It is known from studies conducted in Brazil that TCSV can be transmitted by a number of species of thrips and that some thrips are more efficient vectors than others.
Like other tospoviruses, tomato chlorotic spot virus replicates in its vector as well as in the plant. While the vector status of many thrips species is known with regard to transmission of tomato spotted wilt virus, only five thrips species have been tested for their ability to transmit TCSV.
The host range of TCSV also is not well known and needs further study. The virus has been found to cause diseases in the field in tomato as well as commercial hydroponic lettuce and escarole crops in Brazil.
Other hosts include solanaceous crops such as pepper, husk tomato, tobacco, as well as several legumes including peanut, cowpea, and bean. This list is the result of artificial inoculations in greenhouse studies but demonstrate the ability of these species to be a host. No plants have been reported to be immune. This is most likely the result of limited host range studies on this virus.
Without more information on which thrips species are able to vector TCSV (there are more than 140 thrips species in Florida) and the identity of alternative hosts, it is not possible to make specific recommendations for the management of TCSV. However, there are some strategies developed for TSWV that are likely to be helpful in the management of other tospoviruses in tomato crops.
The use of virus-free transplants, insecticides to control thrips, rouging infected plants, SAR elicitors such as Actigard (Acibenzolar-S-methyl, Syngenta Crop Protection), and UV-reflective mulch will likely be effective in managing TCSV.
Consult UF/IFAS recommendations for currently labeled insecticides for thrips control in Florida tomatoes.