Question
We have a tree at lake of the ozarks and I think it is a oak and we have noticed that there is a sawdust type of dropping around it on the ground and deck. It reappears after cleaning it up. It is a mature tree and we don't want to loose it. Is there anything we can do to help it and kills these pests that are causing the damage??

Answer
It could be just that droppings form caterpillars eating the foliage. Take a set of binoculars and look at the leaves and see if any are showing signs of being eaten (holes in the leaf or parts of the foliage gone. IF so it is a caterpillar and they do little harm to mature trees and their life cycle is short and the droppings will go away in a couple of weeks. On large trees it is next to impossible to get spray up to the foliage so there is not much that can be done. There is a soil applied insecticide called Bayer advanced Tree and shrub insect control (here is a web link). It is applied to the soil around the tree and the roots take it to the foliage and when an insect feeds it is killed. It works best when applied in the early spring when the leaves are beginning to leaf out. Depending on the size of the tree this will take a good bit to treat. http://www.bayeradvanced.com/find-a-product/tree-shrub-care/12-month-tree-shrub-