Imidacloprid use & mite infestation

Asked September 25, 2016, 5:36 PM EDT

Good evening. In a recent UMD garden newsletter (July?) there was a reference to the observation that shrubs treated with Imidacloprid for preventative pest control were highly suspectible to mite infestations for periods extending beyond the initial treatment as well as the labeled product duration. This has been my experience in my home ornamental garden. 10 years ago I treated with Bayer Advanced Tree & Shrub Insect Control. For the past three years I have been working towards being organic, to include no pesticide use of any kind. In addition I have been actively building the soil, releasing lab reared beneficial insects to try to increase their numbers and changing the varieites and spacing of my plantings to support the "good bugs" continued presence. How long will the effect of the pesticide use remain? Any suggestions on how to reduce the presence of mites next summer other than those measures I have noted above? Thank you for your advice. I was not able to locate more info on your website on this topic.

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3 Responses

You are headed in the right direction, good for you.
We are not aware that imidacloprid is still active after ten years.
Here is the National Pesticide Information Center hotline number, they may be able to give you info on this: 1-800-858-7378.
Where are you seeing the mite damage now? How are you identifying them?
During the next growing year, feel free to contact us with questions as you have them, and we'll be happy to help.
Clearly focused digital photos can be attached directly to these questions, and are helpful for identifying what is happening in your landscape.
Here is our page on spider mites: https://extension.umd.edu/hgic/spider-mites-flowers-and-groundcovers

cm

Good Morning,

In our front garden I am seeing the mite damage on my boxwoods and my viburnums. Our arborist from Bartlett Tree has confirmed this issue on each of the above and is working with us on the predatory mite releases.

In our back garden I see these present on the deciduous hollies and amidst the clematis vines. This issue was confirmed as well.

As he instructed me in how to identify the pests I now know to look for the webbing, the sucking damage evident on the leaves and how to use a white piece of paper (shake the insects from the branches of the shrubs onto it) allowing me to look at these under the magnifying glass.

Right now I am observing the red spider mite.

Thank you for providing me the phone number to the NPIC.

Jean

Horticultural oil, insecticidal soap or a strong stream of water might be your best bets.

ECN