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Douglas Fir Insect Mitigation #745508

Asked April 21, 2021, 1:45 PM EDT

Hi, My name is John. My family and I are landowners in Larimer county in rist canyon, near Buckhorn Mountain. The question I have pertains to the Douglas fir and in particular what type of insecticide and application method we can use to protect them from Tussock Moth. We are assuming that the issue is the moth, but have not formally verified. We have had several old growth trees that have symp[to=ms that seem very similar to the "wilt Disease" that is described in insect series fact sheet 5.542 "Douglas fir Tussock Moth as a pest of the urban forest". Ultimately, we are looking for more information on the type of insecticide and how to apply it. We are willing to contact a professional if needed to apply the product. These douglas firs are beautiful forest giants and we hate to see them wilt, so we are reaching out to you for more information. Kindly, John Dellenbach

Larimer County Colorado

Expert Response

Hi John,

While the actual insecticide is something you could purchase, application could be difficult, since many are tree sprays. Few homeowners have the equipment needed to spray the upper canopy of the trees. Because these are high-value trees, I would recommend you consult with a certified arborist to discuss options and treatment recommendations. You can find an arborist at www.treesaregood.com

The other place to consider asking would be the Colorado State Forest Service: <personal data hidden>

The state forest service is much more knowledgeable about these situations, since my focus is home horticulture. 

Alison O'Connor, PhD Replied April 21, 2021, 2:52 PM EDT

This is great. Thank you for your help and direction.  

The Question Asker Replied April 21, 2021, 3:09 PM EDT

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