Sacramento, California - CDFA’s Office of Pesticide Consultation and Analysis (OPCA) is a division of the agency’s Office of Environmental Farming and Innovation. OPCA works with scientists in California’s academic community to provide unbiased consultative and economic impact information to the Department of Pesticide Regulations (DPR) on potential pesticide regulatory impacts and pest management alternatives. The program also funds research to fill important data gaps. Controlling pesticide spray drift has been an important topic in California given the potential human health impacts and new practical solutions are always in demand.

Orchard growers have a new practice that can reduce spray drift from their orchards. The technique involves driving two spray rigs in-parallel on either side of the outer row of trees, with the outside rig spraying only air inward to contain the spray within the orchard. A separate pass with one sprayer is required for proper coverage of the outer row, this time with only the inward-pointing spray nozzles turned on. The technique is being called “interference perimeter spraying” and was developed by researchers from University of California and the Coalition for Urban & Rural Environmental Stewardship (CURES). Funding was provided by OPCA.

“While the practice still needs further evaluation to ensure that control of the targeted pests is maintained, we have confidence that the inference perimeter spraying can be used effectively now by orchardists, especially if spraying occurs near sensitive sites such as waterways or public roads,” says Parry Klassen, Executive Director of CURES. “Many growers already have multiple sprayers in operation so using this technique is very doable at no added cost.”

The research was part of a project that tested spray drift management techniques for protection of surface waters. The project also included a number of publications on spray drift stewardship and a video (below) showing interference perimeter spraying.