Tomato Spotted Wilt virus
TSWV = Tomato Spotted Wilt Virus
Causative agent and transmission
This is a quarantine virus, transmitted by insects (thrips), which can be hosted by a large number of plants such as the Nightshades, the tomato, the potato, the Composites, and many decorative or wild plants.
It is to be found generally in warm climates favourable to thrips, and therefore more commonly in southern early production areas than in potato-seed areas.
Description of symptoms on crops
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On crops: in current-year infection, brown blemishes and round or concentric necrotic ring blemishes can be observed which dry up and then fall off. The attack starts at the top of the plant, with symptoms ranging from discoloration or chlorosis of the top to necrosis and death at the apex. Necroses on the stem can also be seen.
When infected the preceding year, the plants can suffer from dwarfism, curling of the leaves, crinkling and necrotic blemishes.
TSWV lesions sometimes have a necrotic aspect around a central green area.
On tubers: deformation of the tubers, bursting, cracking and dark stains on the surface or under the skin. In some cases, there are internal rust-type stains, but occasionally concentric rings appear combined with rot.
- This quarantine parasite is covered by regulatory measures;
- Be careful of the environment (avoid proximity to tomato greenhouses);
- Use certified seed.