How to Kill Bugs on Kale Naturally

When bugs attack your kale plants, you want to fight back. Fortunately, there are natural ways to kill the many different insect pests that plague these greens.

Once I’ve planted my kale and watched the leaves grow, I’m not exactly happy to see big chewed holes or lots of little bites. But I realize this is just part of gardening.

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The first thing to do if you see insect damage on your kale is identify the pest causing it. Even if you don’t see the beetle itself, the type of bites on the leaves can serve as clues.

Common kale pests and how to control them

Read on to learn more about identifying and controlling pests.

Aphids (family Aphididae)

Aphids are a family of small insects with soft bodies and sucking mouthparts. Large groups of aphids often appear on kale plants, giving them a fuzzy or mottled appearance.

The bugs themselves suck the juices from the plant, which can lead to discolored leaves. Aphids also produce a sticky substance called honeydew that can cause fungal growth.

If there are only a few aphids on your plants, you can spray them off with a garden hose or remove them by hand. Remove and discard leaves infested or damaged by aphids. You can put these on your compost heap.

If you have a large aphid infestation, one option is to release ladybugs. These beneficial insects eat aphids in large numbers. However, you must release a large number of ladybugs for effective control.

Be sure to look for captive-raised ladybugs rather than ladybugs collected from the wild and shipped elsewhere.

Another useful insect in the fight against aphids is the parasitic wasp Aphelinus abdominalis. This wasp not only eats the pests, it lays its eggs in live aphids.

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When the eggs hatch into larvae, the aphids die and turn into a dry shell known as a mummy. Once they reach maturity, the adult parasitic wasp chews a hole in the mummy and emerges – ready to do battle with more aphids!

A. abdominalis can be introduced to your garden when they are in the larval stage – in the mummy. You can buy 250 of these hungry beneficial insects from Arbico Organics and watch them destroy your aphid population!

Since aphids have soft bodies, they can be effectively controlled by spraying with neem oil. Neem oil is made from the seeds of the neem tree.

To use neem oil, dilute it according to the product instructions and spray it on your kale plants. It is best to reapply neem oil every seven days. While you can use it until the day you harvest, you don’t want to swallow it right away. It is worth noting that neem oil can be toxic to bees.

Insecticidal soaps can also be used to kill aphids. Check the label carefully to see if it is suitable for edible crops and note how close to harvest it is safe to spray.

The best time to apply insecticidal soap is morning or evening when temperatures are cooler. Avoid spraying kale in sunny conditions, as this can burn the leaves and damage your plants.

Read more about aphid control here.

Flea beetles (Chrysomelidae family)

These little beetles like to chew on your kale, leaving tiny pits and holes in the leaves.

Although these beetles are small, they often arrive in large numbers and can do a lot of damage.

If these beetles are eating your plants, you can use a number of different natural products to kill the bugs.

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Diatomaceous earth (DE) is a powder made from the fossilized remains of tiny organisms called diatoms.

This substance is sharp on a microscopic level and harmful to the respiratory tract and mucous membranes of all kinds of harmful insects such as flea beetles. But it is harmless to larger creatures such as humans and dogs.

Once you sprinkle DE on your plants, the flea beetles will die. Be sure to only use food grade DE around kale and other edible plants.

Pyrethrins are broad-spectrum insecticides composed of compounds derived from flowers in the Chrysanthemum genus. Products containing pyrethrins kill a variety of insects, including flea beetles.

To use, spray the desired product on your kale plants, these compounds work by affecting the nervous system of insects and products quickly kill pests.

Another natural insecticide that kills beetles is spinosad. This compound is derived from soil-dwelling bacteria.

It can kill pests on contact, but it is more effective when ingested. After spraying your plants with spinosad, the flea beetles will die within two days.

Neem oil is another option that can be used to treat flea beetles.

Harlequin bug (Murgantia histrionica)

Harlequin bugs are shield-shaped, with black and red or black and yellow markings. They lay their black and white eggs in groups of six on the undersides of leaves.

These insects have sucking mouthparts that they use to drink the sap from leaves. This results in white spots called dots. If an infestation gets big enough, plants can turn brown and wilt.

Small numbers of the insects can be controlled by picking adults and eggs and placing them in soapy water.

Harlequin bugs can also be controlled with sprays of neem oil, pyrethrin, or spinosad.

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Insecticidal soaps can also be used to control harlequin bugs. They don’t actually kill the insects, but they can soften their shells so that other insecticides become more effective.

Imported Cabbage Worm (Pieris rapae)

The imported cabbage worm is the juvenile stage of a small white butterfly also known as a cabbage butterfly. These green caterpillars can quickly devour kale leaves if not controlled properly.

Cabbage worm signs are large bite marks or missing edges of the plants. Other signs are round green frass or feces – these things eat a lot, and it shows!

If you notice these worms, you can control them by physically removing them from your plants. Just pick off the worms and egg masses and place them in a container filled with soapy water.

Another method of control is the use of the bacterial insecticide Bacillus thuringiensis kurstaki (Btk). After you spray this bacteria on your plants, the insects will ingest the product and die. A variety of Btk products are available from Arbico Organics.

Crops can usually be harvested the day after application, but remember to always check the label when spraying edible plants with this product.

Keeping your kale plants pest-free

Chances are your plants will be attacked by some kind of insect at some point in their lives. Lucky for you, you now know how to kill some of these big pests naturally!

Let us know in the comments if you’re having trouble controlling pests on your leafy greens, and what methods you use to deal with them.

Try these suggestions to read on to learn more about planting, growing, and harvesting kale:

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