Try Beetle Banks for Organic Pest Management

Beetle banks are a simple way to attract and maintain a population of beneficial insects near your crops.


| November 2014



Beetle banks in a field

A native grass beetle bank at Grinnell Heritage Farm, in Iowa.


Photo by Andrew Dunham, Grinnell Heritage Farm

Using native beneficial insects for pest and weed control serves to reduce or eliminate the need for chemical pesticides while improving the biodiversity of your farm or garden. With the inspiration and instructions in Farming with Native Beneficial Insects (Storey Publishing, 2014) from The Xerces Society, you can learn to identify beneficial insects and implement a host of projects designed to improve habitat for them.

You can purchase this book from the MOTHER EARTH NEWS store: Farming with Native Beneficial Insects.

Providing shelter for beneficial insects can enhance their ability to survive overwintering, and offers them protected areas for egg-laying and pupation. Common types of shelter include the crowns and understories of tall bunch grasses, thick piles of dead brush, decomposing logs, stumps and snags, and similar features.

Beetle Banks

Beetle banks are a habitat enhancement intended to provide shelter for a specific group of beneficial insects: predatory ground beetles. Beetle banks consist of long, elevated earthen berms planted with perennial bunch grasses; occasionally the bunch grasses are interplanted with native wildflowers. These banks provide undisturbed winter cover for ground beetles adjacent to cultivated fields, and are intended to promote rapid movement by beetles back into crop fields when warm weather returns the following year.

The beetle bank concept originated in Great Britain to provide habitat for beetles and other beneficial insects that had declined due to the loss of hedgerows and other habitat adjacent to cropland. British farmers have used beetle banks successfully to control grain crop pests like aphids and wheat blossom midges; in some cases they have eliminated the need for pesticides altogether. Additional research suggests that various ground beetle species supported by beetle banks may feed extensively on weed seed, and can play an important role in suppressing crop weeds. Despite these promising results, beetle banks remain largely untested in the United States, especially outside the Pacific Northwest.

Effectiveness of Beetle Banks

Researchers in Britain wanted to find out whether beetle banks could help reduce cereal aphids in winter wheat. To answer this question, they constructed barriers at various distances from the beetle banks that blocked beetle movement into wheat fields. They then measured the abundance of aphids and aphid predators on either side of the barriers. The researchers found that aphid populations were larger in wheat when barriers blocked predators such as ground beetles, rove beetles, and linyphiid spiders. The impact of the predation by beneficial insects and spiders on aphids declined as distance from the beetle banks increased.





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