Hogs and Hazelnuts: adaptively managing pest spillover in the agricultural-wildland matrix
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Date
2021
Authors
Penkauskas, Calvin
Journal Title
Journal ISSN
Volume Title
Publisher
University of Oregon
Abstract
Pest spillover from wildlands to farms can create conflict between wildland conservation and agricultural production. For example, the key economic pest of hazelnuts in Oregon’s Willamette Valley is the filbertworm (Cydia latiferreana), a moth hosted by the native Oregon white oak (Quercus garryana). Oak stands near hazelnut orchards can sustain source populations that compound pest pressure in hazelnuts throughout the growing season. This dynamic is of conservational concern as historical oak habitat has been greatly reduced and what remains is almost entirely on private land, often in proximity to hazelnut orchards. Here, we present of a novel strategy to reconcile this conflict by using hogs to reduce pest pressure through prescribed grazing. From 2018 to 2020 we prescribed hog-grazing in early fall to glean filbertworm-infested acorns from an oak woodland floor. Hogs were both highly successful at reducing the total number of infested acorns and the ratio of infested acorns the following year. Despite an oak masting year in 2019, grazing reduced both the emerging and adult mating population of filbertworms the following year. We did not measure significant changes in woodland understory vegetation, suggesting hog-grazing may not entail tradeoffs for understory vegetation. Our results demonstrate that prescribed grazing in oak patches can be an effective strategy to reduce filbertworm source populations. By benefiting both conservation and farmers, this novel pest management approach provides a model for similar challenges and conflicts across the agricultural-wildland interface.
Description
1 page.
Keywords
Oaks, Silvopasture, Source-Sink Dynamics, Grazing, Non-timber Forest Product