One morning, your potato plants look lush and full. Dreams of hash browns, soup, and loaded baked potatoes fill your thoughts. The following day, your plants look like they’ve been attacked. Half-eaten leaves, skeleton-like stems, and ugly orange larvae are all over your plants. To save your potato harvest, you need to take action fast. Here’s how to get rid of Colorado potato beetles!
What Are Colorado Potato Beetles?
The Colorado potato beetle, Leptinotarsa decemlineata, goes by several names. People call them potato bugs, ten-lined potato bugs, or those yucky orange things on the potato plants. Despite their name, they don’t only affect gardens in Colorado, either!
These six-legged insects munch potato leaves with wild abandon. Potato beetles and their larvae can decimate your potato patch in short order. The adults are squat, oval, and humpbacked. They have the same general shape as a ladybug.
An adult potato beetle is easy to identify. The head is orange with black spots, and the back is yellow-orange with black stripes. Ten stripes, but you don’t need to count them. If you find an insect matching the description, covered in lines that run head to tail, it is probably an adult Colorado potato beetle.
Potato beetle larvae are soft-bodied and dull orange, with two rows of black spots down the sides. The larger they get, the more plump and humpbacked they look. Young larvae are tiny and rapidly enlarge as they feed.
Not Just Your Potatoes Are at Risk
Colorado potato beetles, especially their larvae, will also eat other plants in your garden. Anything in the Solanaceae (nightshade) family is fair game, and they will readily munch on your eggplants, tomatoes, and pepper plants. Alternate hosts include wild nightshades and ground cherry.
The Lifecycle of Colorado Potato Beetles
The adults emerge from the soil in spring at about the same time as your new potatoes. They will mate and then lay eggs in groups on the undersides of leaves. You may see these clusters of bright orange eggs clinging to the bottom of a potato leaf. They are easily recognizable. Each adult female can lay over 300 eggs, so they are worth finding and eliminating.
Larvae hatch and begin to eat and can finish growing in 10 days if the temperatures are warm. Larvae then drop off to the soil and become pupae. Two or more generations can occur during one growing season in some climates.
Once you have learned the signs of potato beetle damage, a quick daily walkthrough can reveal their presence. Grab a cup of coffee and go take a look before work. Check daily in midsummer—they work fast.
Look for these signs of potato beetles:
Adult beetles are either crawling on plants or dropping to the ground to hide when you approach in spring.
Clusters of football-shaped orange eggs on the undersides of leaves.
Defoliation, especially of new tender leaves.
Small dull orange or brick-colored larvae. The first two instars are small and can be hard to see.
Control and Prevention
If you have a potato beetle infestation, it’s time to get to work, and there are several actions to take.
Prevention and Monitoring
The best way to prevent potato beetles from derailing your future spud enjoyment is a little prevention and monitoring. Like any pest, their numbers will swell when conditions are ideal, so get a head start on thinning their ranks.
Remove alternate hosts. Soon after emergence in spring, the adults will need to feed. If your potatoes are not up yet, they will look for other plants like nightshade and ground cherry. Keep those out of your garden and surrounding property to deny them food.
Choose early maturing varieties of potatoes. You can plant these quick-producing varieties at the usual time of year. They will be winding down when the heavier infestations occur mid to late summer. You can also plant these varieties later in spring to avoid providing food to emerging adults. Without a food source, they will search elsewhere to lay their eggs.
If the infestation was particularly nasty, consider taking a year off from growing potatoes. The adults will emerge and fly off to find a new food source. If your neighbor is growing potatoes on the next lot over, this may not work. Adults will travel a quarter mile or farther to find suitable egg-laying conditions.
How to Get Rid of Potato Beetles
Potato beetle larvae can quickly decimate plants. More than 30% defoliation will affect your harvest, and severe loss of leaves could even kill the plant. Early monitoring and detection are crucial to getting this problem under control. Don’t let it wait until the weekend.
Grab a pail and some gloves
Potato beetles in the garden can often be removed by hand. A little soapy water in the bottom of an old ice cream pail and a pair of gloves make this task easier.
In the early part of the summer, watch your plants for adult beetles or for tell-tale damage to leaves. Pluck off any adults you see and dispose of them.
As the season progresses, watch for eggs on the undersides of the leaves. They are bright orange and clustered together. Smash them with your thumb or rip the leaf off and destroy it.
Once the larvae appear, brush or shake them off into your pail. You will need to do so daily for a week or two to control the flush.
A fowl solution
If you don’t want to drown them, the larvae can be a treat for your chickens. As a kid, our chickens figured out that a tasty morsel would come if I had an old ice cream bucket in my hand. The hens would start to cluck and run around, maneuvering for the best position to grab a larva as I dumped the bucket over the fence. In a few seconds, no more bugs.
A flock of chickens or ducks loose in your garden might not be advisable during the middle of summer. But, they can be excellent helpers during spring and fall. Chickens especially will scratch and hunt up larvae, pupae, and adult bugs that would otherwise spend the winter in the soil of your veggie patch.
They will also make eggs out of late-season weeds, weed seeds, and other garden problems. If you have some backyard hens, try turning them loose in your garden a few weeks before planting or after harvest.
Sprays and other applications
Many people are finding that the Colorado potato beetle is growing resistant to common pesticides.
Some gardeners have found success against larvae with Neem oil, but it should be used sparingly and only if removal does not work. Neem oil can cause problems with beneficial insects and pollinators in your garden.
Natural predators can be encouraged but seldom will solve an infestation for you. They are more effective at keeping populations low if they are present in the first place. Keep habitat for predatory wasps, songbirds, and ladybugs on your property.
Bluebirds, in particular, can be beneficial gardening partners. Provide some perching spots and nest boxes near the garden. Building up your garden’s natural defenses is a long-term project that pays dividends for years to come.
However you combat them, the key to saving your potato crop is early detection and early action. Keep an eye out and get hopping at the first sign of a problem.