How to Rid Your Garden of Potato Beetles
Potato beetles are voracious predators that first skeletonize your potatoes and then move on to your peppers, eggplants and tomatoes. Getting rid of them requires vigilance on your part.
Know your enemy!
The Colorado Potato Beetle originated in Colorado where it munched happily on native buffalo burs, a relative of the potato. Then European settlers arrived in 1859 with potatoes and the beetles switched to this more abundant crop. They munched their way back east, following the potato "trail" moving up to 85 miles per year until they arrived on the East Coast in 1874.
The adults overwinter in the soil. In the spring, they emerge, start eating your potatoes' foliage, then mate and lay eggs on the leaves. A female potato beetle lays 10 to 30 eggs at a time, up to 350 in her short lifetime. The eggs hatch within two weeks. The resulting larvae are more voracious eaters of your potatoes' foliage than the adults.
Rotate and cultivate
Once the larvae have eaten their fill, they dive down into the soil to pupate into adults. If it is late in the season, they overwinter in your garden, emerging in the spring to begin the cycle again. You can break the cycle in the fall with a deep cultivation of your soil which will kill the larvae. You should be practicing crop rotation so any remaining beetles will emerge in the spring and not find anything in the immediate vicinity to eat.
A good rule of thumb is not plant potatoes in the same spot for two years. Most gardeners make that three years because they divide their gardens into quadrants, each quadrant containing a different family of vegetables and rotate their quadrants every year.
Barrier methods are always a good way to prevent potato beetles from getting to your potatoes. Dig a trench around your potatoes and line it with plastic creating a bare area and fooling the beetles into thinking that there is nothing planted in the vicinity. Beetles are not too bright.
Another good barrier method is floating row covers. They are "floating" because you just lay them loosely over your plants. The thin polyester material allows light and rain to get in but keeps insects out. Since potatoes do not require pollination, you don't have to worry about preventing pollinating insects from getting to your plants. Row covers also keep in heat, warming the air and soil and encouraging your plants to grow faster.
Pick your own
If you aren't squeamish, you can manually pick off the adults and larvae from your plants and kill them by either squishing them or dropping them into a container of soapy water.
The enemy of my enemy is my friend
Use salt hay as a mulch in your garden and you will be attracting beneficial insects such as predatory wasps and lady bugs which like to nest in the hay and eat potato beetles! Add a birdbath and insect eating birds will drop by for a quick dip and a snack of beetles. Establish a small pond or wetlands near your garden and toads will take up residence. They will visit your garden and eat their fill of potato beetles and other insects.
Colorado potato beetles are a scourge that we brought on ourselves by introducing potatoes in their environment. You can keep their numbers down using a variety of methods.
More on garden pests
© 2014 Caren White
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