Black Wart
Synchytrium
Black Wart
Causative agent and transmission
The potato wart disease is a serious potato disease caused by a primitive fungus: Synchytrium endobioticum.
The spores released by the tumours can remain alive for many years (up to 30 years) in the soil, in encysted form.
The attacks are particularly severe in a cold and damp climate.
Description of symptoms on tubers
(clic on photos to enlarge)
Tumours, due to cell proliferation, of variable size (from a few mm to the size of a fist), develop on:
- the lenticles,
- the stolons,
- parts of the stem under the ground.
Attacks are mainly below ground level, however, under very damp conditions, they can also be observed above ground.
Unlike powdery scab or root-knot nematodes, the tumours never form on the roots.
The tumours are initially whitish, turning black later on and releasing a black spore powder. The tumours can turn green if they are exposed to light.
The disease can develop during storage.
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Control
- A quarantine parasite subject to compulsory control procedures (cultivation prohibited, restriction on imports from infested areas, etc.);
- Use of healthy seed potatoes;
- Use of resistant varieties;
- No effective chemical control.
