Little Brown Droppings From Trees

Q: What on earth are these zillions of little brown droppings that are falling from our trees? They’ve been falling for about a week now, covering much of the deck with messy stuff that sticks to your shoes, and when rained upon turns to mushy mud. Anything we can do to stop it? 

A: The first thing to do is to cancel any parties you might plan involving the deck. The brown particles are the droppings of oak caterpillars living in the tree, gorging on leaves, and discharging the aftermath onto your deck. At night, you can sometimes hear what sounds like a light rain, but it’s not water; it’s caterpillar dung falling on the leaves. There’s nothing you can do about it. The tree is likely too tall to spray, and it can take a long time for systemic insecticides to go to the leaves. Fortunately, the caterpillars are only there for a few weeks, and you can begin entertaining thereafter.