Lettuce & Greens holes in leaves
There are 3 common causes, and they need completely different responses — so working out which one you have matters more than treating quickly.
None of them will normally kill the plant.
Check these two things first
- Push a finger into the soil, two knuckles deep. Wet soil plus a wilting plant means too much water, not too little — and it is the commonest reason a plant is dying. Dry soil plus crisp leaves means the opposite. The leaves look nearly identical either way, so the soil is what tells you.
- Turn a damaged leaf over. Half of all diagnoses live on the underside: fuzz means downy mildew, fine webbing means spider mites, clusters of insects mean aphids. Nothing on the top of a leaf is as informative.
Most garden problems are cosmetic and resolve without treatment. Reach for a spray last, not first.
The 3 causes, and how to tell them apart
1.Cabbage Worms & Loopers
TreatablePest
Velvety green caterpillars, well camouflaged along the midrib, chewing ragged holes through leaves. Green-brown pellets of frass collect in the heart of the plant. White butterflies fluttering around the bed are the adults.
How to know it is this one
Ragged irregular holes through the leaf, not neat edges or notches.
2.Flea Beetles
TreatablePest
Dozens of tiny round holes through the leaf, as though it had been hit with birdshot. The beetles are minute, dark and shiny, and jump like fleas when disturbed — which is usually all you see of them.
How to know it is this one
Many small round shot-holes rather than a few large ones.
3.Slugs & Snails
TreatablePest
Irregular holes with smooth rounded edges, chewed from the middle of the leaf as well as the margins, and a dried silvery slime trail across leaves or soil. Damage appears overnight and there is nothing to see by day.
How to know it is this one
Silvery dried slime trails on leaves, pots or soil.
Still not sure?
The diagnostic key adds two more questions — which part is affected and where the trouble started — and those usually settle it.
Run the diagnostic key