Paying attention to an outbreak of tomato chlorotic spot virus (TCSV) again in this growing season

What we have seen in tomato fields 

We have observed an outbreak of tomato chlorotic spot virus (TCSV) in some tomato fields. It could become a great concern again in this growing season. As everybody may remember that the first outbreak of TCSV occurred in the Homestead area during the 2014 growing season. It caused up to 30% yield loss. The virus has always been present but the infection was not so severe in the last couple of years. However, due to the impact from other commodity practice changes associated with unpredictable weather, a severe damage has appeared in some fields since last week. Growers have to take out the infected plants (Figure 1), which results in a lot of plants missing (Figure 2).

Figure 1. Workers are pulling out infected plants and removing from the field (Q. Wang)

Figure 2. Many plants have been removed (Q. Wang)

Symptoms of TCSV infection

At the beginning, the top leaves show tiny spots or smears. Then, the plants develop necrotic lesions and chlorotic spots, and ring spots on leaves, stems, petioles, and fruit. Finally, wilting, bronzing, and stunting of the plants, and eventually death from the top of the plant (Figure 3).

Figure 3. Symptoms of TCSV infected (Q. Wang)

Management

Two types of thrips, western flower thrips, and common blossom thrips are vectors of this virus. They can transfer the virus from infected plants to health plants. Therefore, spray frequently to control these thrips can reduce the infection. Chemical insecticides such as Radiant, Exirel, and Brigade, etc. may help reduce the population of these thrips. Please follow the label for handling and application of any chemical pesticide. For details about TCSV and other tospoviruses, please refer to the link:  Tospovirus of Tomato and Management.