By Clint Thompson
Tomato spotted wilt virus (TSWV) should be a concern for Alabama vegetable growers. Two outbreaks since 2020 is cause for concern, especially since there were only two outbreaks in the previous 40 years.
Alabama farmers must be mindful of controlling western flower thrips, the major vectors of the disease, says Paulo Gimenez Cremonez, Auburn Assistant Professor and Extension Specialist.
“It is absolutely important to keep monitoring the populations of this species. Since it’s the major one, it must be responsible for most of the damage that we are seeing. We need to anticipate this, so it doesn’t happen more often like it is,” Cremonez said.
Cremonez spoke about the TSWV concerns at the recent Alabama Fruit and Vegetable Growers Association Conference and Trade Show. Tomato spotted wilt virus affects tomatoes, peppers and peanuts. Symptoms include stunting, bronzing, ring spots, necrosis and deformed fruit. The 2020 outbreak occurred in St. Clair County, while the second outbreak occurred in tomatoes.
“This has been a very severe outbreak that we had, damaging in some of the tomato sets, as they reported up to 75% of plants affected. This is very concerning because the varieties are resistant varieties. They should be resistant to the virus,” Cremonez added. “However, the virus seems to be overtaking this resistance and still affecting the tomato plants. It is urgent because there are some weather situations that can be affecting the insect behavior in a way that will still cause a lot of pressure into the plants. Plants that are supposed to be resistant will be showing symptoms as well.
“We need to find varieties that are more resistant than the ones that we have available. We have to continue monitoring and trying to control the western flower thrips the best we can.”
Management Options
Producers can use blue sticky cards to monitor for thrips. Refuge areas, such as weeds, need to be controlled. Biological control measures with predatory mites and pirate bugs can also be utilized.
Resistant varieties and reflective mulches are also recommended.
Conventional growers should always remember to rotate their insecticides.