Putting buffers to work
Vegetative barriers can physically stop pesticides from reaching sensitive areas.
This living barrier in the middle is part of an Oregon State University study to measure how much drift is trapped from applications made in the nearby orchard on the right. photo courtesy of osu
Vegetative buffers near orchards and vineyards can provide a variety of benefits, including keeping pesticides where they are intended. To make buffers more appealing, qualifying growers can receive cost-sharing funds to ease the financial burden of establishing them.
Buffers are defined as a strip of land that is maintained in permanent vegetation and is untreated, explained Sandy Halstead, agricultural initiative specialist for U.S. Environmental Protection Agency’s Region 10. Buffers have important functions in pesticide management, she said, noting that they can help trap pesticide residues in the soil, slowing down their movement to allow time for the pesticide to be taken up by the environment.
Halstead, who is based in Prosser, Washington, added that the federal government recognizes the conservation role that buffers play in reducing pesticide risks, thereby provides for the establishment of buffers in cost-sharing programs of the U.S. Department of Agriculture.
Halstead shared the “good, bad, and ugly” of buffers at a recent integrated pest management workshop held in Toppenish, Washington, focusing her talk on edge-of-field buffers. The workshop, sponsored by the Integrated Soil, Nutrient and Pest Education Project, called iSNAP, highlighted to growers pest management practices that are low-cost, effective, and protect water resources.
The iSNAP project is a collaborative effort of university and agency specialists from Oregon, Washington, and Idaho and receives funding from the USDA Risk Management Agency, Western Integrated Pest Management Center, and the Oregon State Integrated Plant Protection Center.
“Buffers can remove up to 50 percent of pesticides, 60 percent of pathogens, and 75 percent of sediment before it leaves the field,” she said. “Buffers are one of the best tools to use to reduce pesticide losses from your field.”
Field borders, or permanent barriers along the edge of the field, are one of the easiest types of buffers to use, she noted. They should be 12 to 20 feet wide and run the length of the field, according to guidelines from USDA’s Natural Resource Conservation Service. The borders, which also minimize wind erosion and help protect wildlife habitat, can be driven on, mowed, and hayed. But she cautioned that they
may increase rodent populations.
Buffers are also valuable to integrated pest management programs, providing overwintering sites and vegetative diversity for insect beneficials and predators. She noted that USDA and university researchers have found that plants in the rose family, planted adjacent to fruit orchards, provide good habitat for a parasitic wasp important in the biological control of pandemis and oblique-banded leafrollers. Additionally, clovers, alfalfa, sunflowers, and yarrow are good hosts for other beneficials like assassin bugs, big-eyed bugs, and damsel bugs.
Halstead said that buffers are taking a more prominent role on pesticide application labels, with EPA requiring “set backs” on some of the newly revised labels, such as Guthion (azinphos-methyl) that requires a 60-foot set back from sensitive areas.
“A living buffer or barrier can take up or physically stop the pesticide from moving onto sensitive areas,” she said. Evergreen plants make good choices for barriers, as they don’t lose their leaves in the winter when dormant sprays may be applied.
But growers need to be aware of the bad and ugly sides of buffers, she said, explaining that if buffers are not maintained, they can be host for unwanted pest species. “The type of plants you have planted in the buffer can impact the insects that you attract.
“Lush, green weed growth on field edges can attract pests that you don’t want, so you may need to mow the field edges before undesired species move into the orchard,” she said.
The legal issues of buffers—set back requirements due to pesticide labels or court-ordered buffers—can be distasteful to some growers, she acknowledged. For some pesticides that have a surface water advisory on the application label, buffers are required, and mixing and loading may be prohibited within a certain distance from wells.
“You need to carefully read the pesticide labels because some have changed,” she reminded growers. “Take extra care if the labels have water advisory statements. You may want to select pest management options that use alternative materials instead of dealing with the water advisory requirements.”
“All buffers cost money,” Halstead admitted. “They take land out of production and take time to put in.” But cost-sharing programs can ease some of the financial burden from buffers.
She encouraged growers to investigate cost-sharing programs of USDA’s conservation arm, the Natural Resources Conservation Service. Qualifying applicants can receive up to 75 percent of the cost of installing field borders and up to $150 per acre for irrigation, grading, and related work. Applications, due in November of
each year, are submitted to the local NRCS office.
Growers should contact their local NRCS office for detailed information.
To learn more about NRCS cost-sharing programs, visit: http://www.nrcs. usda.gov/programs/eqip/.