Colorado Potato Beetle

If you see in your garden a small yellow beetle with black stripes over its wings and black spots just behind its head, say hello to the Colorado potato beetle. The humpbacked larva is equally distinctive: red with a row of black spots along each side. For years it lived quietly in Colorado feeding on weedy potato relatives. But at some point after the potato was well established in North America, its ancestors learned a new trick. It's been the bane of potato-growing gardeners ever since.

Potatoes are its first love, but this beetle will eagerly consume leaves of potato relatives eggplant, ground cherry, peppers, tomato, and tomatillo.

Colorado potato beetle prefer cold winters. While found as far west as Arizona, Nevada, western Oregon and western Washington, it is by far more common on the East Coast as far south as Virginia, then from there to the north west through Wyoming. The adult beetles overwinter in the soil, emerging in the spring to lay clusters of yellow eggs on leaf undersides. There are one to three generations per year, depending on the part of the country.

Controls

• Apply a thick, organic mulch, which makes it hard for emerging beetles to reach plants in spring.
• Monitor plants carefully and hand-pick at first sign of infestation. Examine plants while holding a container of soapy water to dispose of any you find.
• Natural enemies include birds, spined soldier bugs, and beneficial nematodes.
• Spray Bacillus thuringiensis tenebrionis (also known as San Diego strain), while larva are small to manage major outbreaks.

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