CORVALLIS, Ore. — Oregon farmers are cultivating predator-prey relationships and reducing the need for pesticides by adopting new pest management strategies that encourage beneficial insect populations.
Farmers from Lebanon, Philomath, Grants Pass and Portland are teaming up with Oregon State University scientists to limit farm pest populations by restoring and conserving habitat for insects that perform important pollination and predation roles within fields and farms. These beneficial insects come in many forms, but are often bees, spiders, or warrior beetles.
"Predacious ground beetles are the ground troops of the insect world," said Gwendolyn Ellen, the project lead for OSU's Farmscaping for Beneficials Project. "They eat a range of pests from aphids to slugs and as a result many farmers are very interested in creating habitat for them. To serve this need we're working with farmers to build ‘beetle banks’ within their fields."
Beetle banks are swaths of raised land four to six feet wide in the fields that are planted with native bunch grasses and provide shelter for predacious ground beetles. In healthy populations the beetles are capable of devouring a variety of destructive organisms that can inflict thousands of dollars of damage to organic and conventional crops.
"The banks act as a beetle hotel, providing a safe, protected environment where beetles can over-winter, and remain present in the fields during a time of year that has previously been unoccupied," said Paul Jepson, director of OSU's Integrated Plant Protection Center.
The center has created three large beetle banks at OSU's Hyslop Field Research Station. Center researchers and area farmers are testing different native bunch grasses as suitable plants for the beetle banks. The grasses act as a trap crop for agricultural pests in the field and create an untilled area for the beetles to live undisturbed, said Ellen, adding that the native bunch grasses are noninvasive and should not compete with crops.
"Farmers are individually designing the banks to fit into their diverse farming systems," she said. "This is not something that there is a prescription for and this approach results in a bank unique to each farm. With each bank we are gathering more data to share with other people."
The interest in beetle banks and other habitat like hedgerows and diverse configurations of flowering plants suited to beneficial insects may be a response to the changing scope of farming and food production, said Jepson.
"As Oregon agriculture has become increasingly larger in scale, fields have been isolated from natural habitats that act as reservoirs for natural enemies and pollinators," said Jepson, who is a professor in OSU’s College of Agricultural Sciences. "Today's intensive vegetable farming practices simplify farm landscapes and reduce food and habitat resources for beneficial insects. Farmers can create specific habitat for these insects that does not currently exist on most farms."
Beetle banks fall under the heading of conservation biological control, a type of management that is an easy fit for organic farmers who must conserve biodiversity, and for conventional farmers wanting to benefit from the opportunities diverse farm habitats create, said Ellen.
"Biological pest suppression and pollination can occur in agricultural ecosystems that are well connected with natural areas and the diverse habitats that may surround intensively managed fields," she added. "These ecological services have existed in nature for as long as plants and insects have inhabited the earth. Building beetle banks and other habitat are a means to recreate farm diversity."
The Integrated Plant Protection Center’s Farmscaping for Beneficials Project is a partnership between OSU, Xerces Society, Oregon Tilth and area farmers. The project, with its unique collaborative approach, was recently awarded a two-year grant from the USDA's Sustainable Agriculture Research and Education Program for the establishment of beetle banks on Oregon farms.
"The farmers help design the project at all levels; their expertise leads the science at OSU while Xerces Society and Oregon Tilth are the experts at helping make the program work at the community level," said Ellen, adding that programs like those at the Integrated Plant Protection Center help farmers look at their farms in ecological terms.
Individuals interested in exploring beneficial farm habitat are welcome to attend a Farmscaping for Beneficials Farm Walk highlighting conservation hedgerows. The walk will take place at Sauvie Island Organics and the Howell Territorial Park on Sauvie Island in Portland on Aug. 18. For more information about the walk, the Integrated Plant Protection Center and the Farmscaping for Beneficials Project visit the website at http://ipmnet.org/.