How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Anna Your Own Question
Anna, Teacher, writer, biologist
Category: General
Satisfied Customers: 11461
Experience:  Great research skills, variety of work experiences, teaching experience.
Type Your Question Here...
Anna is online now
A new question is answered every 9 seconds

We have several Colorado spruce trees that have been infested

Resolved Question:

We have several Colorado spruce trees that have been infested with spider mites. The heights of the trees vary between 20 and 30 feet. It is extrememly expensive to have them sprayed by the arborist and are trying to find out what treatment, chemical or otherwise is something we could do yourselves?
Submitted: 5 years ago.
Category: General
Expert:  Anna replied 5 years ago.

I'm sorry to hear that you're having this problem. Some additional information will help me to answer your question.

Have you sprayed for any other insects in the last few months?

In what part of the country do you live?

How much damage are the mites doing?

Are the trees being grown for lumber or for decorative purposes?

Thank you.

Customer: replied 5 years ago.


We have not sprayed for any other insects.

Eagle, Colorado

Hard to say how much damage. Trees still look OK. There is some browning in the needles and we can see the mites.

Decorative purposes.


Expert:  Anna replied 5 years ago.
Thank you for getting back to me. I’m working on your answer and will post it as soon as I have it typed up. Please don’t respond to this post as that can lock me out of the question. I’ll be back shortly.

Expert:  Anna replied 5 years ago.
Thank you for waiting. When mite damage isn't extensive, the best choice can be to do nothing. Colder weather often causes a decrease in the mite population. then, when it warms up again, other insects that prey on mites increase. When insecticides are sprayed, it kills these insects, and the mites then thrive.

However, if the mites are causing your trees to look unattractive, you may want to go ahead and treat them. In order to kill mites, the trees have to be thoroughly covered with the miticide. You can rent the equipment to do this, but it will be difficult with such tall trees. If you know someone with a tractor and an air blast mist-blower, that is most effective. Some people manage to get good coverage using a backpack sprayer.

As for what to sue, there are a number of good miticide available and you should be bale to find some in a garden center or nursery. Some of them include Avid, Cinnamite, Cygon, Envidor, Lorsban, Metaystox-R, Ornamite, Sanmite, and Savey. Most of these will require a repeat application. Some are only available to professionals in certain states. All require caution in use because they can be toxic to you, as well as the mites. A safer alternative is to sue a horticultural oil, but if applied incorrectly or at the wrong time of the year, such oils can damage the tree. They need to be applied in warm weather when the tree is growing to avoid harm. Regardless of what spray you sue, you should eb aware that mites are difficult to control, and through coverage is essential. each tree must be sprayed until wet, and make sure the undersides of the needles are covered. Many mites prefer to feed on the underside.

A lot of homeowners choose to pay an arborist because of the difficulty of spraying large trees, and because arborists ahve access to the most effective chemicals. However, if you can get the equipment and have the patience to properly apply the spray, there's no reason you cna';t do this yourself. I hope that whatever you decide to do, you'll soon be rid of the mites.

Anna and 13 other General Specialists are ready to help you