How to Grow: Controlling Flea Beetles

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There’s nothing more discouraging than working hard prepping your vegetable garden soil, making beds and sowing seeds, only to find as soon as the little plants emerge they get eaten by insects. One of the worst culprits this time of year is flea beetles.

These small, black beetles literally hop when disturbed, hence the common name. This also makes it hard to catch and kill them. You’ll notice their activity on radishes, kale, and arugula seedlings as they emerge from the soil. However, you’ll even find them on transplants of broccoli, eggplant and spinach. Their damage looks like small, shotgun holes in the leaves. Look closer and you’ll find the beetles. If severe enough they can kill your plant. Once the plants are larger, flea beetles aren’t a problem.

While you can cover the seeds and seedlings to prevent some damage, invariably, flea beetles will get under the row cover. I find the best control is to create an environment they don’t like on the leaves.

I’ve be dusting my seedlings with diatomaceous earth or kaolin clay. Diatomaceous Earth or DE is made from the skeletal remains of tiny diatom sea creatures. It’s dusty and sharp for little insects. Kaolin clay is like potter’s clay and also leaves a dusty film on the leaves. These dusts don’t harm the plants, but make life unpleasant for the flea beetles. Reapply after a heavy rain. You can also hang yellow sticky traps close to the seedlings to attract and kill the flea beetles or use radishes as a trap crop.

Excerpted from the Vermont Garden Journal on Vermont Public Radio.