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Protecting Plants from the Colorado Potato Beetle

Question. I have a family farm in central Virginia that has a major pest problem. For years, we have grown mostly potatoes for our family. However, we lose a large portion of the crop to the Colorado Potato Beetle. For years we have used liquid and powdered Sevin with 'ok' results. But I would now like to find a more healthy and natural way to fight the bugs. Can you offer any advice on what types of beneficial insects to use and where to buy them? Or is there a chemical that is safe to use? We plant about 15 acres with potatoes, tomatoes, beans, apples, pears, squash, cucumbers, and peppers; and most things do well even though we can't care for them every day as we live over two hours away in Maryland. But the potatoes get torn to shreds by those beetles. Any information would be helpful. Thank you!

    ---Rick in Louisa, Virginia

Answer. Colorado potato beetles are a notorious pest of potatoes—and they can cross over to chowing down on tomatoes, peppers and eggplant when conditions are right. Of course, your absentee status makes any form of pest control much more difficult. The most important tool of farming (and gardening) is always the daily inspection; otherwise you can't catch problems at an early stage.

As you note in your email, the incredibly toxic and dangerous pesticide Sevin is only 'OK' at controlling the pest, and you are wise to move away from it. What's the point of growing food for your children on poisoned soil?

Now if you looked through our A to Z archives, you saw Colorado potato beetles listed as prime candidates for control by toads—so installing a few ponds and big shady areas near your potato plantings would be a good start (and toads eat a wide variety of other farm and garden pests as well). I'd put some birdbaths right in the middle of the potato patches as well, to make a nice destination for potentially hungry avian avengers.

Although I generally don't recommend tilling (because of the weed problems it can create), deep cultivation in the fall and spring is a good idea until you get the problem under control, as the last generation of adults overwinters in the soil near where the previous season's potatoes grew. Unfortunately, they go pretty deep, so you have to till down low. Crop rotation would also be a really good idea—the adults don't have a lot of energy when they emerge from the soil, so make it a long walk for them to get to this year's plants.

And if you do move your potatoes to another location (always a good idea, even without pest issues), consider surrounding them with a trench lined with plastic—this old-fashioned beetle trap can be very effective.

Because potatoes don't need pollination, row covers can provide excellent protection. These thin spun polyester blankets are a staple of organic lettuce and spinach growing—allowing light, air and rain through, but no insects; and pests can't eat plants they can't reach. Good quality row covers will last for years, and they'll improve the quality of your spuds and give you those super-tasty young 'new potatoes' much earlier in the season, thanks to the little bit of extra heat they give the plants.