How to Identify & Manage 4 Kale Pests

Kale is a popular garden crop, but it has certain problems. Learn about 4 common kale pests and how to manage them without synthetic pesticides.

by Jessica WalliserAugust 9, 2019
PHOTO: Jessica Walliser

Kale has become a very popular vegetable. It’s chock full of vitamins and fiber, and it’s delicious as both a baby green and mature leaves. But, kale is not without its problems. There are several pests that enjoy kale as much as people do, and gardeners are often faced with troublesome pest issues when growing this vegetable. Here are some of the most common kale pests and how to manage them organically.

1. Slugs & Snails

These two land-dwelling mollusks are quite fond of kale foliage, especially when it’s young. These kale pests use a mouth full of grater-like teeth to shred the leaves and feed on them. If you have holes in your kale leaves, but don’t spy any insect pests during the day, check the plants at night. Slugs and snails much prefer damp weather and darkness, so you’re most likely to find them feeding on plants during the nighttime or on rainy days.

To manage these two kale pests in your kale patch, lay 2×4 boards between garden rows and flip them over in the afternoon. Collect the sheltering slugs you find beneath the boards and dispose of them in a jar of soapy water. Another option is to use an organic slug bait based on iron phosphate. Sprinkle it around kale plants according to label instructions.

2. Imported Cabbageworms

cabbageworm kale pests
H. Krisp/Wikimedia Commons

These green caterpillars have a faint, creamy yellow stripe running down their side and can grow up to an inch long. They’re the larvae of white, day-flying butterflies. Cabbageworms can be very destructive, leaving skeletonized leaves behind. Often, you’ll find them along leaf mid-ribs and undersides.

Handpicking is a great way to manage cabbageworm caterpillars, but because these kale pests can be difficult to spot, it isn’t always an easy task. Organic pesticides based on Bacillus thuringiensis (Bt) or spinosad are another management option. They’re highly effective when used according to label instructions.

3. Mammalian Pests

white-tailed deer kale pests
Colby Stopa/Flickr

Rabbits, deer and groundhogs also enjoy feasting on kale plants from time to time. Protect plants with a layer of floating row cover (which will also help control imported cabbageworm caterpillars) or deer netting. Even if kale plants are eaten to the ground, they’ll re-sprout once protected and go on to produce a good crop.

Subscribe now

Granular animal deterrents that are labeled for use in the vegetable garden can also be good at repelling these critters. Avoid using any spray repellents, however, as they can lead to a distasteful harvest. Granular products can be sprinkled between crop rows or around the perimeter of your kale patch.

4. Harlequin Bugs

If you’re a southern gardener, you’re probably already familiar with the destructive power of this pest (pictured at the top of this post). Harlequin bugs are black, shield-shaped bugs with red or yellow markings. They’re members of the stink bug family that are most common in the south, though their range has expanded and they’re now found from time to time as far north as New England. They’re very fast maturing and voracious consumers of all members of the cabbage family, including kale. These kale pests feed by sucking out plant juices, leaving discoloration and splotches behind. Often they’re found feeding in masses.

To control harlequin bugs in your kale patch, handpick the insects when you find them, but don’t squish them (unless you want to be exposed to a really bad odor). Protect plants under a layer of floating row cover from germination until harvest. Kale doesn’t need to be pollinated to produce, so row cover is very effective in deterring this pest.