A Closer Look at Viruses Found in Greenhouses This Production Season

Posted by Brian Sparks|November 25, 2023

The researchers and other industry members behind the horticulture educational resource e-GRO recently posted an alert highlighting a wide range of plant viruses, both common and uncommon, found by growers during the 2023 production season. The alert is a photographic guide to viruses found on a wide array of species and can aid in the identification of these problems.

For example, necrotic spotting and ringspots were observed while visiting growers. These symptoms are typical of a virus infection. To confirm, the first step is to test the plant for impatiens necrotic spot virus (INSV) and then tomato spotted wilt virus (TSWV). From experience, INSV is confirmed twice as much as TSWV, therefore it is helpful to begin with that test.

All of the viruses were confirmed with an enzyme-linked immunosorbent assay (ELISA) test. If you suspect a virus problem, have the plants tested by a diagnostic clinic. You can also conduct in-house testing with ELISA kits. It is important to test multiple leaves from the same plant that is exhibiting symptoms. The total leaf area tested should be around 1 square cm.

Once a plant has INSV or TSWV, there are no treatment options to remove the virus from the plant. Discarding infected plants is the only option, and this will help prevent the virus from spreading further. It is important to note that some plants may be asymptomatic, but still have TSWV or INSV. Since the primary method of spreading these viruses is via Western Flower thrips (Frankliniella occidentallis) feeding, it is critical to keep them under control.

Learn more in the complete alert here.