Leaf Miner

This damage appears to be caused by a leaf miner. A small fly or moth lays its eggs beneath the surface of the leaf and when the eggs hatch, the larvae tunnel thru the leaf tissue, consuming the nutrients in the foliage. Once the damage has been done, nothing will reverse it. Chemical pesticides are not effective against this pest because most products won’t penetrate thru the leaf surface and contact the pest. Once the damage has been done to the leaf, it is not reversible. Usually the damage done by these insects is not going to kill the plant unless the infestation is extensive. Suggest you confirm the problem with your horticulturist at a local garden center and if it is leaf miner damage, an organic control containing Spinosad is effective against leaf miners, but spray in the early evening after the bees have returned to their hives. Once the spray has dried it is safe for beneficial insects and has a 7-10 day residual.