I have tent caterpillars near the top of my snow crap tree. Should I be concerned about the need to treat the tree?
Boulder County Colorado tent caterpillar
There are several types of tent caterpillars in Colorado, and while unsightly, many of these can be well-tolerated by plants and trees, and don't require controls. The CSU references (see below) state that "control normally is warranted only where thre is sutained, high levels of defoliation over several years."
The key questions are how much damage (if any) is being done to the tree, if this damage has ocurred over multiple years, and if you are able to reach the tents for manual removal if the unsighliness is the key concern.
Here are two links to information that may be helpful:
Summary Info: http://www.ext.colostate.edu/ptlk//1484.html
If you need more info, I recommend you call the Master Gardener Help Desk Monday, Wednesday or Friday between 9 & noon or 1 & 4 PM to speak directly with a volunteer.
I hope this helps! Good luck,
Master Gardener Volunteer