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Ascochyta fabae Speg.

Mycologia, DEUTEROMYCOTINA, SPHAEROPSIDALES, PHOMACEAE .

Crops attacked: horse bean .

[R]Common Names :

Anthracnose

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

[R]Identification
The fungus can be cultured on growth medium.
The pycnidia can be seen with a naked eye but are more easily detectable with a dissecting microscope.

[R]Description
As soon as the seedling appears, brown spots can be seen on the cotyledons. The leaf spots rapidly grow 10 mm long and affect all the organ : leaves, stems, flowers and pods. The center of the spots becomes necrotic and cuts a hole through the leaf weakening the stem, sometimes causing lodging and pod-splitting while still in full development.
The infected seeds show brown-red round spots.

[R]Biology
The fungus survives in the contaminated seeds which directly infect the developing seedling causing its death (emergence deficiency).
Pycnidia appear at the center of older lesions.

[R]Epidemiology
Frequent heavy rain at the beginning of the growth cycle facilitate the spreading of primary infection sites allowing the pycnidiospores formed in the pycnidia to disseminate.
The spores are transported from the lower to the higher parts of the plant by splashing on the leaves.

[R]Treatement
Choose unsusceptible or resistant cultivars.
Use preventively treated seeds.

[R]Possible misleading
B. fabae but the spots of B. fabae are usually smaller, their colour is more uniform and they have no pycnidia.

[R] Images

  1. Ascochyta fabae , Horse-bean anthracnose (LECONTE M., INRA)
    Horse-bean anthracnose Anthracnose spots on a young horse-bean seedling.
  2. Ascochyta fabae , Horse-bean anthracnose (TIVOLI B., INRA)
    Horse-bean anthracnose Anthracnose spots running together on horse-bean leaves.
  3. Ascochyta fabae , Horse-bean anthracnose (TIVOLI B., INRA)
    Horse-bean anthracnose Cup-shaped anthracnose pycnidium on a horse-bean leaf as seen through the light microscope.
  4. Ascochyta fabae , Horse-bean anthracnose (TIVOLI B., INRA)
    Horse-bean anthracnose Anthracnose spots on horse-bean pods.
  5. Ascochyta fabae , Horse-bean anthracnose (SLAGMULDER C.., INRA)
    Horse-bean anthracnose Anthracnose spots coalescing on a horse-bean leaflet.
  6. Ascochyta fabae , Horse-bean anthracnose (LAMARQUE C., INRA)
    Horse-bean anthracnose Anthracnose spots on horse-bean leaflets.
  7. Ascochyta fabae , Horse-bean anthracnose (TIVOLI B., INRA)
    Horse-bean anthracnose Spots of anthracnose and bursting of horse-bean pods.
  8. Ascochyta fabae , Horse-bean anthracnose (TIVOLI B., INRA)
    Horse-bean anthracnose Anthracnose spots on horse-bean pods.
  9. Ascochyta fabae , Horse-bean anthracnose (TIVOLI B., INRA)
    Horse-bean anthracnose Horse-bean pods that have been severely attacked by anthracnose causing bursting and contamination of the seeds inside.
  10. Ascochyta fabae , Horse-bean anthracnose (LECONTE M., INRA)
    Horse-bean anthracnose Horse-bean stem that has lodged before maturity as the result of an anthracnose attack.

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

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