Next I request a photo of the tree and the damage. Instead she brings me a live sample, all the better! "Webbing, Brown Leaves, Little black spots on paper when shaken, classic mites!" I explain to her that mites can easily be sprayed off young trees, and very little pesticides are available to homeowners for mite treatment. So a good daily spray should knock most of them off. CASE CLOSED!
Mimosa Webworm webbing on Honey Locust.
Then... as I walked towards the office I keep seeing what appears to be feces, and a lot of it. "Wow, I have never seen mite poop before..." I thought. "And I have seen a lot of mites!" Now, unconvinced this was mite feces, I went digging through my tree diagnosis library.
Mimosa Webworm. Yet another invasive species introduced from Asia, and yet another beautiful, yet destructive pest. Apparently this is a common pest of honey locusts, though they seem to be very picky about cultivars, which may explain why I have never seen them until now! The larval form of this pest, the caterpillars, start to appear around Late June and munch on your trees until late summer. August is when the adult form is witnessed and the cycle starts anew.
Usually once damage is noticed, its already too late to treat the insect. These insects should be treated early. Hand picking the caterpillars and inviting birds to feed on the caterpillars is a great form of defense, and a high pressure water hose knocking them to the ground will also help keep the good fight!
So, like every day, I learned something new. I was also reminded that when things seem like an open and shut case, sometimes you have to dig a little deeper and never be afraid to look yourself in the mirror and realize you were wrong. What a great day to get outside and experience something new today!