Necrotic spotting and ringspots were observed while visiting
a grower. These symptoms are typical of what occurs with a
virus. This Alert will aid in the identification of a tomato spotted
wilt virus (TSWV) infection.
A grower pointed out a few New Guinea impatiens that had necrotic patches. The necrotic symptoms were pronounced on the leaves. The plants lacked the typical overall major stunting, twisted leaf growth, and mottling that one also typically observes with TSWV (Fig. 3). Together, both groups of images will provide an excellent visual tool for diagnosing virus symptoms.
A plant was tested for TSWV, and it was 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 from Agdia. 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 TSWV or impatiens necrotic spot virus (INSV), it cannot be removed. 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.
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