pest guide 8
Leafminers are small insects in multiple orders that feed within the leaf tissue (A, on tomato and B, on linden). They can cause blotchy patches on leaves that die. This damage can look very similar to many leaf fungal diseases (C, fungus on Cucurbita and D, tar spot on maple), however, they can be often be easily identified by carefully pulling back the top layer of the damaged leaf blotch. If it is leafminer damage, the dead section will be hollow, and often insect frass or shed skins can be found inside.