Outwitting Colorado Potato Beetles

Pexels Potatoes

The Colorado potato beetle has been a persistent pest for about 150 years, but we’re still trying to “figure out” the nature of this pest. After all, they’re good at adapting.  And so, the Colorado potato beetle continues to happily devour potato leaves.

Why is it important that we control Colorado potato beetles? They’re a formidable opponent — one female can lay 800 eggs on the undersides of a variety of host plant leaves. Depending on the weather, those eggs can hatch within four to fifteen days, releasing the next generation of leaf-devouring larvae. And, if spring arrives early enough and summer lasts long enough, farmers can face as many as three generations of Colorado potato beetles in one growing season.
Because of this, Wisconsin potato growers can’t rely on natural predators to efficiently reduce the beetle population. The birds that feed on the beetles don’t often arrive in Wisconsin until late spring — too late to curb the earlier beetle generations that first emerge after the long winter.

What are sustainable Wisconsin potato growers doing to battle the pest?  They’re working with University of Wisconsin researchers to try and understand what Colorado potato beetles do, where and when they do it and why they do it. From there, the growers and researchers puzzle out means of utilizing that understanding to eliminate or divert the beetles
without damaging the diverse ecosystem. This process of researching, testing and utilizing a variety of measures to manage pests is known as Integrated Pest Management (IPM).

One example of this is initiatives taken by Steve and Andy Diercks, third and fourth generation Wisconsin farmers who run Coloma Farms — a 2,700 acre family farm in Waushara County.

One successful IPM method involves digging trenches along the crop borders, lining them with plastic and then adding a layer of dirt in the bottom of the trench. As the beetles leave their winter shelters looking for the potato plants that will feed them and shelter their eggs, they fall into the trenches. The dust clogs the hairs on their legs, making it impossible for them to get a good grip on the plastic. They’re trapped. And that means there are less beetles breeding in spring, subsequently reducing the pest population for the remainder of the growing season.

So far, this experimental method has worked well — it’s a non-chemical means of eliminating the pests. That said, the researchers and the Diercks will continue to investigate other IPM methods because the plastic used in the trenchs has a carbon footprint they need to be aware of. To minimize that carbon footprint, they will continue to study the Colorado beetle’s preferences in order to place smaller runs of plastic in higher traffic areas.

Read more about the Diercks’ innovative, environmentally-friendly pest management techniques.

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