Long time lurker, first time poster. I volunteer at a historical recreation site and have taken over a relatively young orchard, about 5 years old. Trees have never had any pruning to develop structure or control root suckers, so that has been my focus this year. I actually have three trees with their first apples! This is a site where no chemical controls will be used due to historical period appropriateness.

This past weekend I was doing a little maintenance pruning and noticed a lot of damage to the leaves on several trees. Looked sort of like leaf miner, meandering patches and spots, definately not a disease response, more likely physical damage, not chewed thru, just the top layer. Then on several leaves I noticed what looked like a small slug-type creature, about 3/8" long and 1/8" wide, same sort of locomotion as a slug.

It has been hot and dry, definately not the sort of conditions that a slug could survive on a leaf, on a sunny windy day. Any thoughts as to what this is? TYIA.

Steve