Our ash trees
We have ash trees in our yard that may have the ash bore. They will need treatment. How do we get that done? what is recommended? Dupont was here today to check the trees that they will be removing and he commented that our Ash trees need to be treated. Could you help me with this problem??
Allamakee County Iowa
Thank you for your message and for contacting Iowa State University Extension & Outreach.
Deciding to treat ash trees with insecticide or replace the trees or a combination of both is a difficult and personal decision. There is no one answer and there are no regulations that require you to treat or remove your trees. here is a guide from Purdue University to help you decide.
Insecticides treatments to protect ash trees can be applied to small trees by the homeowner. Large trees (over 20 inch diameter) require professional treatment to be effective. See more about treatments at http://www.extension.iastate.edu/pme/Publications/EAB/PM2084EABManagementOptions091313.pdf
The preferred timing for application is in the spring as the tree is growing. It does work to apply the insecticide when the tree is dormant. The "fall" treatment mentioned on the label would have to be before the leaves start to turn color in preparation for falling off.
Do-It-Yourself treatment should be applied within 12 inches of the trunk after the mulch or grass has been removed. The DIY drench treatment is only effective on trees up to ~20 inches in diameter. See footnote # 3 on page 2 of the pamphlet.