Question
I believe we have a locust tree, although we do not have thorns on it.  The new growth out on the ends of the branches is wilted looking and looks as if something is eating it, or stripping the new leaves off.  Do you know what it is and if there might be another tree that looks like a honey locust without the thorns?  How can we treat it?  The tree is at least 7-8 years old.  Thank you.

Answer
Sounds like locust leaf miner. The locust leafminer is primarily a pest of black locust. Adults skeletonize and eat holes in the leaves; whereas, larvae mine the tissue between the upper and lower-leaf surface (mining damage is the most destructive). Under outbreak conditions, whole hillsides turn gray or brown, often suggesting fall color change. Outbreaks of the locust leafminer are generally more spectacular than destructive. In combination with other stress factors, outbreaks contribute to growth loss and occasional tree mortality.

The locust leafminer is primarily a pest of black locust. Adults skeletonize and eat holes in the leaves; whereas, larvae mine the tissue between the upper and lower-leaf surface (mining damage is the most destructive). Under outbreak conditions, whole hillsides turn gray or brown, often suggesting fall color change. Outbreaks of the locust leafminer are generally more spectacular than destructive. In combination with other stress factors, outbreaks contribute to growth loss and occasional tree mortality.

Adults overwinter in bark crevices or in leaf litter and emerge about the time leaves begin to unfold in the spring. Eggs are deposited on the underside of locust leaflets. They overlap like shingles in groups of three to five and are cemented together by excrement. Upon hatching, the larvae feed collectively in common blister-like mines. Shortly thereafter, they disperse and excavate their own individual mines. Larvae pupate within the translucent mines in July. There are two generations per year.
Control of the locust leafminer is generally not necessary. When aesthetics are involved (such as in a residential or recreation area), control might be justifiable. If control is desired, the best time to treat is in late May or early June when the adults are active and the larval mines are less than ?inch in length. An insecticide with some systemic activity will give the best control. Follow the label instructions for application method, timing, and dose rate.
Check with your local nursery for a systemic insecticide for leaf miners. There are some that you spread on the ground and water in and the tree takes the insecticide up to the leaves.
The good news is the trees will re foliate and later in the summer it will be hard to tell if there was a problem in the spring.