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

University of Minnesota Extension
www.extension.umn.edu
612-624-1222

Extension > Garden > Diagnose a problem > What's wrong with my plant? > Deciduous Trees > Black Walnut > Dark spots or blotches

Print Icon Email Icon Share Icon

Black Walnut > Nuts > Dark spots or blotches

1 of 2
  • Image: Husk maggots 1
  • Image: Husk maggots 2
  • Image: Husk maggots 3

Husk maggots
Rhagoletis spp.

  • Larvae (maggots) feed inside the husk during mid-summer
  • Larvae feeding causes husks to become slimy, dark and stick to the shell
  • Do not harm nutmeat but fruit becomes unappealing and difficult to handle
  • More information on Husk fly maggots...
2 of 2
  • Image: Anthracnose 1
  • Image: Anthracnose 2
  • Image: Anthracnose 3

Anthracnose
Gnomonia leptosyla

  • Leaflets have circular brown spots surrounded by yellow tissue
  • Infected leaves turn yellow, then brown on the margins, curl and eventually fall off
  • Dark brown to black spots or blotches form on nut husks
  • Nuts drop prematurely
  • More information on Walnut Anthracnose...

Don't see what you're looking for?

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