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Mycologia, ASCOMYCOTINA, DOTHIDEALES, PLEOSPORACEAE .

Crops attacked: cabbage, .

Black leg

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

[R]Description
This fungus plays a role in damping off.
Necrotic injuries are observed around the collar and at the base of the stem of infected plants.
Sometimes these wounds are further marked by black pycnidia, which evolve into necrotic tissue.
Adult plants.may have brown rot.
Petioles which have been in contact with the ground have brown, dry spots on their underside.

[R]Biology
(see rapeseed).
The fungus forms black pseudothecia (perithecia) under crop debris which contain the septated ascospores and constitue the primary inoculum.
The pycniospores are produced on the spots in the pycnidia and contribute to the spread of the fungus.

[R]Epidemiology
(see rapeseed).
Once established in the crop, the pathogen is spread by rain.
Humid weather favours an epidemic. Infected seeds are a source of contamination.

[R]Treatement
Disinfect the soil.
Use treated seeds.
Maximize aeration by seeding lightly in straight lines.
Pulverize a locally recommended fungicide on young plants.

[R]Possible misleading
.

[R] Images

1. Phoma lingam , Crucifer collar rot (BASF)
   Crucifer collar rot Detail of a phoma spot on a rapeseed leaf showing many black dots (pycnidia).
   
2. Phoma lingam , Crucifer collar rot (BASF)
   Crucifer collar rot Necrosis caused by phoma on rapeseed collar.
   
3. Phoma lingam , Crucifer collar rot (BASF)
   Crucifer collar rot Longitudinal cut of a rapeseed collar infected by phoma.
   
4. Phoma lingam , Crucifer collar rot (BASF)
   Crucifer collar rot Rapeseed collar broken by Phoma lingam .
   
5. Phoma lingam , Crucifer collar rot (RENARD M., INRA)
   Crucifer collar rot Phoma spots on a rapeseed leaf.
   

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

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