Slugs, snails, and cutworms are the main nighttime kale pests chewing holes in your leaves after dark. These three feed in the cool, damp hours and then hide before sunrise, so you rarely catch them at work. That is why the damage seems to show up out of nowhere from one morning to the next. The good news is that each one leaves a different kind of mess, so you can name the culprit fast once you know what to look for.
"It's the birds," my neighbor said over the fence, pointing at the ragged Lacinato by the back fence. So I grabbed a flashlight after dark and checked the zone 6 bed with him. Half a dozen slugs sat right on the leaves, mouths working through the green. I found more tucked under the lower foliage where they had been hiding all day. I pulled three off one leaf before he even bent down to look. The birds were asleep, and they had nothing to do with it.
Telling the night feeders apart is easier than you might think once you know the signs. Slugs on kale leave silvery slime trails across the leaves and the soil, plus large ragged holes with smooth edges. Snails do the same damage and add a hard shell you can spot in the morning. The slime is the dead giveaway, since no other pest leaves that shiny track behind. Look closest along the lower leaves and the leaf undersides, since that is where these soft pests stay cool and moist. If you see a trail and big chewed gaps but no insects, you are dealing with slugs or snails.
Cutworms play a different game, and the damage they cause looks nothing like a chewed leaf. With cutworms kale growers lose plants in a way that stops you cold the first time. These fat caterpillars hide in the soil by day and crawl up at night to sever young seedlings right at the base, near the soil line. You walk out to find a healthy seedling toppled over like someone snipped it with scissors. Big established plants usually shrug it off, but a row of new transplants can vanish in two nights. Brush back the soil right around a cut stem and you will often find the grey, curled caterpillar resting an inch down.
Plenty of pests work the day shift too, so check in daylight before you blame the dark. Cabbage worms and loopers are green caterpillars that match the leaf color and feed on the undersides. Aphids cluster in tight colonies along the stems. Flea beetles punch tiny shot-hole specks across the leaves. Harlequin bugs leave pale stippled patches where they suck the sap. Most of these hide under the leaves, so flip a few over every time you scout the bed.
Knowing the culprit is half the battle, and the controls for these nighttime kale pests are simple once you do. You should hand-pick after dark with a flashlight and drop slugs, snails, and cutworms into soapy water. Make sure to ring your plants with a slug barrier like crushed eggshells, diatomaceous earth, or copper tape. Slip cardboard collars around new seedlings so cutworms can't reach the stems, and float a row cover over the bed to block egg-laying moths and beetles.
Spray Bt on the leaves for cabbage worms and loopers. It is the caterpillar control Bonnie Plants recommends because it kills the worms while sparing bees and other helpers.
Start with the flashlight check tonight before you buy anything. A five-minute walk tells you exactly what you are dealing with, and that beats guessing every time. Hand-pick what you find, ring your seedlings with a barrier, and set collars on the youngest transplants. Do those three things and your kale leaves stay whole through the next round of growth.
Read the full article: Kale Plant Guide: Grow, Harvest and Enjoy
