08/18/2026
One of the most useful skills you can develop as a gardener is learning to read plant damage like a detective reads a crime scene. You do not always need to catch the pest in the act. The pattern left behind almost always tells you exactly who the culprit is.
Clean round holes punched straight through a leaf point to slugs. Beer traps and evening hand-picking, when they are most active, are your best defense. Ragged holes paired with small dark specks of frass, which is just a polite word for insect droppings, signal caterpillars. Hand-picking and Bt spray, a bacterial insecticide that specifically targets caterpillars without harming beneficial insects, handle those well. When a leaf is reduced to lace with only the veins remaining, that skeletonized look is the calling card of Japanese beetles, best managed by hand-picking into soapy water.
Stippled yellowing combined with fine webbing means spider mites, which thrive in hot, dry conditions and are easily managed with a daily water spray on the undersides of leaves where they cluster. Curled, sticky, distorted foliage is classic aphid damage. Sticky is the key word there, since that residue is aphid honeydew. A strong water blast followed by insecticidal soap usually clears them out. Silver streaking across leaf surfaces points to thrips, tiny insects best caught with neem oil and blue sticky traps.
Winding, squiggly trails tunneled through leaf tissue are the work of leafminers, whose larvae literally live and feed inside the leaf. Simply removing affected leaves is often enough. Semicircle notches cut cleanly from leaf edges look alarming, but that is leafcutter bees, and they are not pests at all. They are valuable native pollinators using leaf pieces to line their nests, so please welcome and protect them. Shotgun-style tiny holes scattered across foliage indicate flea beetles, controlled with row covers on vulnerable transplants.
A hole in a stem or trunk with frass around it signals a vine borer tunneling inside, which sometimes requires splitting the stem to extract the larva directly. Leaves rolled tightly along their edges point to leafrollers, managed the same way as caterpillars with hand-picking and Bt. And if branches are stripped bare seemingly overnight, deer are almost always the culprit, best kept out with an eight-foot fence or a reliable repellent.
Learning these patterns saves you time, saves your plants, and helps you avoid reaching for a spray when hand-picking or a simple barrier would do the job just as well, no matter where you are gardening in the country. 🌿🔍
