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Didymella lycopersici Klebahn


Crops attacked: tomato .

[R]Common Names :

Didymella stem rot

Identification, Description, Biology, Epidemiology, Treatement, Possible misleading, Images

Pycnidia visible with a naked eye.

Brown clear-cut lesions occur at different levels along the stem, usually at soil level and show characteristic dark dots (pycnidia).
The plant wilts and dries up.

The fungus easily penetrates through the wounds caused by routine trimming.
It survives on plant debris in the soil and spreads from the infected lesions on the collar and the stem through the tools handled in cutting and land works, air draught and water splash.
Dissemination occurs mainly through conidia (produced by the pycnidia) and not through ascospores.
The disease is rarely seed-borne.

The fungus is present in previously desinfected and recontaminated soil.
The optimum temperature for the development of the disease is 19 - 20 C.
Its outbreak is more severe in heavy moist land and in crops sown in cold soil.

Use healthy seeds.
Avoid wounds and overabundant watering.
Remove the affected plants.

[R]Possible misleading

[R] Images

  1. Didymella lycopersici , Didymella stem rot (BOUHOT D., INRA)
    Tomato didymella stem rot Didymella lycopersici appearing at the base of the stem of a tomato plant.
  2. Didymella applanata , Spur blight (FAIVRE-AMIOT A., INRA)
    Spur blight on tomato Spur blight on tomato stem.

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HYP3 on line : Species (scientific name), Diseases (common names), Glossary, Crops.

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