Knowledgebase

Sugar maple verticillium wilt? #770467

Asked September 02, 2021, 4:59 PM EDT

I have a client whose sugar maple is showing symptoms and signs consistent with verticillium wilt. I have attached a few photos. Please let me know two things: 1) Is there a need to send in a sample to get a definitive diagnosis, and 2) Can this disease be effectively managed without putting his other trees at risk? Other trees on the property are all small (less than 10 inches dbh) except for a ponderossa pine that is about 20” dbh). Other trees on the property include snow 1 crab apple, 2 hawthorn, 2 autumn blaze maples, 1 Armstrong maple and 3 green ash.

Boulder County Colorado

Expert Response

Hello David,

Thank you for your question and photos and for your patience in waiting for a reply.

Yes, you do need to submit a sample for confirmation of the Verticillium fungus.  The closest lab to Boulder is the Jeffco Extension Plant Diagnostic Clinic, located at the Jeffco Fairgrounds, open Tu-Fri 8:30-4:30.  Sample fee for commercial client is $15 and includes culture.

If the tree does have Verticillium wilt, management strategies include pruning out diseased wood, and maintaining tree vigor by fertilizing with “balanced” fertilizers (10-10-10 [N-P-K]) and watering. High-nitrogen fertilizers may increase damage.

Ash, catalpa, elm, sumac, and maple are the
most common hosts in the Rocky Mountain Region.  Verticillium is a soil fungus that infects trees through damaged roots (typically at planting time).  Good cultural control is the best management strategy protecting susceptible trees.

References on Verticillium Wilt

  • USDA
  • CSU

    • Best regards,

    Mari

    Jefferson County Extension of Colorado State University Replied September 21, 2021, 5:23 AM EDT

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