This week I am hearing about leaf miner injury in various plants. You look at the leaf and see tunnels winding around between the tissues of the leaf. I have not seen heavy infestations that skeletonize the plant, however, they are unsightly.
Caused by a little black fly laying eggs on the leaf. The eggs hatch and the little larva burrow into the tissues of the leaf. The type of leaf miner is specific to the plant (they do not cross to other plants).
I have seen them on hollyhock, beets, bean, tomatoes, and columbines this year. Certain species also attack cottonwood, birch, pine trees, vine crops, peppers, and eggplant.
Since the larva is in the leaf, control is hard. For flowers (non-eatables) you can use a systemic insecticide. For the garden, it is best to pick off the damaged leaves and dispose of them. A newer way is to use neem oil which reduces the number of larva becoming adults.