Knowledgebase

Honey Locust tree disease #719823

Asked September 01, 2020, 12:08 PM EDT

My tree trimmer told me that my honey locusts were diseased and he mentioned the name but I cant remember it. I would like to get your opinion on what it is and the best way to treat it if possible. We really love these trees and hope that they can be treated. Thanks
Dede Frain - I live in golden

Jefferson County Colorado

Expert Response

Thank you for contacting us about your honeylocust. I'm not able to enlarge your photos enough to see the bark damage on the limb but I'm assuming this is your concern. The leaves in the last photo look healthy.
 Has the tree suffered any damage? Hail? Too heavy snowfall? lawnmower? poor tree trimming?  Most likely, your tree has undergone the stress of last October's early freeze and this May's late freeze—and this summer's drought. 
Can you see holes in the bark? Tunnels or channels below the bark in the tree? Are there dry drips of "sap" out from any wounds?
The damage may be caused by the honeylocust borer. The adult lays her eggs in early spring, usually near a wound, and when the larvae hatch later in the spring they make tunnels under the bark. When  they become adults and emerge, they bore through the bark to get out. 
Treatment includes eliminating the stressors and avoiding damage to the bark —when possible. (Certainly hail damage is out of your control!) Maintain healthy practices like adequate watering during hot weather and also in winter if snowfall is scarce. 
It's important that evidence of the honeylocust borer be verified before considering any chemical treatment, and this can only be effective in early spring when the female is laying her eggs. Suggestions can be found in the links below.  
If this diagnosis doesn't seem likely, please get back to us and consider bringing a sample of the damaged tree limb, if possible, to our clinic. 

https://extension.colostate.edu/topic-areas/insects/insect-and-mite-pests-of-honeylocust-5-571/
https://pestadvisories.usu.edu/2017/04/27/honeylocust-pests/#:~:text=This%20pest%20is%20usually%20an....


Jefferson County Extension of Colorado State University Replied September 02, 2020, 6:39 PM EDT

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