Skip to Main navigation Skip to Left navigation Skip to Main content Skip to Footer

University of Minnesota Extension

Extension > Garden > Yard and Garden > Vegetables > Diseases of cucurbits > Alternaria leaf blight

Print Icon Email Icon Share Icon

Back to Diseases of cucurbits

Alternaria leaf blight

Michelle Grabowski

Alternaria leaf blight is caused by the fungus Alternaria cucumerina. This disease is most problematic on melon but can also occur on cucumber, pumpkin and squash. Alternaria leaf blight does not commonly infect fruit but can reduce yield and quality through reduced plant vigor and sunscald of exposed fruit.

Plant with leaves with jagged edges

M. Grabowski, University of Minnesota


Important biology

Alternaria cucumerina can be carried long distance on wind currents and can be spread within the field by splashing water. Wet rainy weather favors diseases, and damage can be very severe in warm, wet conditions. The fungus survives from season to season in plant debris.


close up of leaf with brown, dead spots at edges

G. Holmes, CA Poly Tech

  • © Regents of the University of Minnesota. All rights reserved.
  • The University of Minnesota is an equal opportunity educator and employer. Privacy