We have two huge walnut trees in our front yard, and our neighbor called us and then another lady stopped by and knocked on our door to warn us that there is a boring beetle that is going through Utah that is killing all of the walnut trees.

What happens is that the beetles bore into the tree and dig around under the bark, which cuts into the vascular (water-carrying) system of the tree, and the beetles also carry some kind of a fungus that infects the tree and causes problems. Affected trees will die from the top-down (because water is not making it up there), so you will see leaves at the top start to whither and brown and/or you will have bare branches up high at the top of the tree.

We had an arborist come last week, and both of our trees are infected, but we *might* have caught it early enough that we can save the trees, and it will be $1200-$1500 to treat our two trees, with zero guarantees that it will work.

If you have walnut trees that are not showing symptoms and you don't want them to die, you should call an arborist and have them come treat your trees with the pesticide & fungicide (apparently it will protect them for two years), because if you wait until they are symptomatic, it's likely too late to save them.