Unfortunately, Colorado potato beetles aren't just in Colorado—and they don't damage just potatoes, either. These striped insects infest plants throughout North America, including tomatoes, eggplant, peppers, petunias, and (of course) potatoes. The good news is, you can easily prevent and get rid of Colorado potato beetles by following some basic good gardening practices. Here's how.
How to Get Rid of Colorado Potato Beetles
What are Colorado potato beetles?
Colorado potato beetles (Leptinotarsa decemlineata) are widespread invaders of a host of garden plants. When these beetles attack, they're typically present in large numbers. Also known as ten-lined potato beetles, they are ravenous feeders that quickly cause severe damage. Heavy feeding ultimately reduces your harvest by stripping plants of their energy-making foliage.
These pests were originally native to the eastern side of the Rocky Mountains, where they fed on buffalo bur, a plant native to the area. After potatoes were introduced to this region, the beetles decided they liked them, too. They began spreading eastward via potato fields, reaching the East Coast by 1874. They've been a menace to both farmers and gardeners ever since.
In spring, adults emerge from overwintering in the ground or garden debris to lay eggs on foliage. These quickly hatch into red larvae that eat more and more as they grow. The larvae then turn into pupae and finally emerge as striped adult beetles that can fly to other plants.
How do I prevent Colorado potato beetles?
The good news is, Colorado potato beetle prevention is easy. Plus, it will also help keep a wide variety of other pests at bay. Here are our top strategies to keep potato bugs out of your garden.
- Commit to a clean garden. Remove plants as soon as they're harvested. At the end of the growing season, clear the garden of all plant debris, including dead leaves. This is a good gardening practice for controlling virtually any insect or disease.
- Pull weeds. When beetles emerge from the soil in spring, they'll settle on weed host plants, such as ground cherry or other nightshades. Keep areas near the garden weed-free, too.
- Use row covers. A floating row cover is a lightweight piece of white spun fabric that lies over plants like a blanket. It lets sunlight, air, and water through, but prevents beetles from landing on leaves. Anchor edges well to prevent beetles from gaining access to plants. Unlike plants that fruit, you can leave potato plants covered as long as necessary because they do not have flowers that depend on bees for pollination. Learn more about row covers.
- Add mulch. A layer of mulch can make it more difficult for beetle larvae to burrow into the soil to turn into pupae and ultimately adult beetles. Apply a 4-inch-thick layer when plants are 3 to 4 inches tall.
- Repel them. Grow plants that repel Colorado potato beetles, like eucalyptus, catnip, marigold, nasturtium, coriander, onion, and tansy.
How do I control Colorado potato beetles?
If you spot Colorado potato beetles, you must take quick action before they severely damage your plants' foliage, ultimately hurting your harvest. Here are the best ways to get rid of Colorado potato beetles.
- Hand-pick beetles. If the number of beetles is relatively small (and you can stomach it), they can be removed by hand. Knock them into soapy water.
- Crush eggs. Crush any clusters of red-orange eggs on leaf undersides. It's a good idea to wear gloves for this task, as the crushed eggs produce a foul odor.
- Spray the insects. If beetle numbers are large, treat them with an approved insecticide that won't harm plants, such as Ortho® Insect, Mite & Disease 3-in-1, according to label directions. Coat adult beetles with the spray for best results, but note that adults may prove difficult to kill. Focus your efforts on future infestations by spraying leaf undersides thoroughly to kill newly hatching pests, which are more susceptible to insecticides.
- Go natural. Look for Bt for beetles (Bacillus thuringiensis var. tenebrionis), which is a naturally occurring bacterial treatment that kills young potato beetle larvae. It's less effective on older larvae and adults. Though they can develop resistance to some pesticides, the beetles don't develop resistance to this bacteria. Spray within 3 to 4 days of when eggs start hatching. (PS: This Bt product is different from the version sold for caterpillar control, often under the name Dipel or Thuricide.)
Need more info and local pesticide recommendations? Contact your regional Extension agent. You can find the nearest Extension office through the Cooperative Extension System map.
Don't let Colorado potato beetles ruin your bumper crop. By acting quickly and applying the right products, you can stop these pests in their tracks and get back to enjoying your homegrown produce.