Northwest forest plants defeat pests and diseases!Author(s): Natasha Vizcarra; Rick Kelsey; Joe Karchesy
Source: Science Findings 194. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 5 p.
Publication Series: Science Findings
Station: Pacific Northwest Research Station
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Societies use biologically active chemicals as medicines and pesticides to protect human and agricultural health. But widespread use of synthetic compounds raises concerns about their safety, and resistance development in targeted pests.
To find safer alternatives, scientists turned to native plants and trees in Pacific Northwest forests using multiyear exploratory surveys. Researchers collected samples from different plant and tree parts for extraction and toxicity testing with a simple brine shrimp bioassay. These bioassays detected strong biological activity in heartwood extracts from four cedar and one juniper species.
In followup experiments, researchers discovered that heartwood extracts from yellow-cedar (Callitropsis nootkatensis), incense cedar (Calocedrus decurrens), Port Orford cedar Chamaecyparis lawsoniana), and western juniper (Juniperus occidentalis) had strong toxicity or repellent activity toward mosquitoes, ticks, or fleas. A patent was issued for compounds with activity toward these pests. It has been licensed to a company interested in developing them into commercial products.
In other experiments, researchers found extracts and compounds from cedar heartwood possess strong antimicrobial activity against Phytophthora ramorum, the pathogen causing sudden oak death. To mitigate movement of P. ramorum spores by hikers and cyclists, forest health specialists have used western redcedar (Thuja plicata) heartwood chips on a popular hiking trail on the Rogue River-Siskiyou National Forest, where retreatment continues to show promising results.
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CitationVizcarra, Natasha; Kelsey, Rick; Karchesy, Joe. 2017. Northwest forest plants defeat pests and diseases! Science Findings 194. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 5 p.
KeywordsHeartwood extracts, sudden oak death, phytophthora ramorum, nootkatone.
- Antimicrobial activity of extracts and select compounds in the heartwood of seven western conifers toward Phytophthora ramorum
- Antifungal activities of three supercritical fluid extracted cedar oils
- Host range determination and fungicide resistance assessment of Phytophthora lateralis isolates from horticultural nurseries in Oregon
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