Leaf blight

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David B. Langston, University of Georgia, Bugwood.org
Is this a Minor Pest?
Yes
Minor Pest Title

Leaf blight (Alternaria dauci)

Minor Pest Description

The disease is caused by the fungus Alternaria dauci. Dark-grey to brown, angular spots form on leaves. Surrounding tissue yellows and affected leaves eventually die. Older leaves are attacked first and only in very severe cases are younger leaves affected. Large spots can girdle leaf petioles and kill leaves without spots developing on individual leaflets. During warm moist weather, dying of affected leaves may occur so rapidly that plants appear scorched. This fungus can also cause seedling damping-off. The fungus is seed-borne and survives in the soil crop debris.

Minor Pest What to do.
  • Use resistant hybrids where available.
  • Use certified disease-free seeds. In case of using own seeds hot water treat seeds. For information Hot water treatment of seeds click here.
  • Avoid parsley in crop rotation and practice good field hygiene.
  • Enhance aeration of crop field by less dense crops and ridge cultivation.
  • No or little N-fertilisation.
  • Monitor fields regularly to be able to react properly.
  • Copper treatments can reduce infection. For more information on copper click here.
Minor Pest Position
2
Minor Pest Firstcontent
160
Pest Type
fungal
Host Plants
Carrot