application process of imidacloprid as a soil drench #154773 - Ask Extension


application process of imidacloprid as a soil drench #154773

Asked September 28, 2013, 10:25 AM EDT

RE: ASH TREES  (2 # 8 - 10 " dia.) can a pro-active action of applying imidacloprid  as a soil drench as a possible corrective measure  for   re: Emerald Ash Borer, be justified when the trees are asymptomatic.

Jefferson County Colorado

Expert Response


Remember that as of this date there has been no confirmation of EAB in Denver County. At present the Colorado Department of Agriculture and USDA-APHIS are working to determine the extent of the present infestation in Boulder. We can hope that it is limited to the single site, but expect a greatly intensified effort in the upcoming year to better delimit the current range of EAB in Colorado.    

Annual application in spring (mid-April to mid-May) is best.
Apply imidacloprid as a drench around trunk, about 24 inches from the trunk, in accordance with label directions. Apply to moist soil, not mulch over soil.

If EAB expands its territory into much of the Metro area, it may be useful to combine soil drench treatments with trunk sprays and/or cover sprays of leaves.
Cover sprays (bifenthrin, permethrin, cyfluthrin) mid-late May will kill adults as they feed on leaves.
Trunk sprays: lower 6 feet of trunk using dinotefuran (Safari), mid-late May.

Side effects of these insecticides:
Robert Cox Replied September 30, 2013, 3:39 PM EDT
Just a reminder - there is NO need to treat ash trees in Jefferson County as of this date.  Using an insecticide now or even next year on Jeffco ash trees is not warranted or justified.
When or if Emerald Ash Borer is found within 10 miles of your location, then preventive insecticide use may be warranted.
Robert Cox Replied October 23, 2013, 1:43 PM EDT

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