26 Apr 2018
Test Your Irrigation Water for Phytophthora
Redekar, N.R. and Parke, J.L. (Oregon State University)
Phytophthora is a plant pathogen that can infect a wide variety of nursery plant species, and it spreads in irrigation water. In this article, we will describe how you can test your irrigation water for Phytophthora using baits. We present a case study of a large nursery where baiting was used to test the efficacy of their water treatment. Although this nursery recycles 90% of their irrigation water, we showed that they were successful at controlling Phytophthora contamination with their chlorination treatments.
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American Nurseryman Redekar and Parke 2018 (657 KB)
6 Apr 2018
Phytophthora Communities in a Western Oregon (USA) River
Redekar, N., Eberhart, J., and J.L. Parke (Oregon State University)
One source of oomycete (Phytophthora and Pythium) contamination in nurseries and greenhouses is the use of untreated water from ponds and rivers. Next generation DNA sequencing was used to detect species of Phytophthora and Pythium in irrigation water originating from a river. Research highlights: 1) Pythium and Phytophthora are the most abundant oomycete genera found in river water, 2) the oomycete species in river water fluctuate seasonally, 3) leaf baiting is the best method to detect active plant pathogens, particularly Phytophthora species, and 4) next generation sequencing technology is a very effective, sensitive and semi-quantitative method for detecting Phytophthora and Pythium in water or soil.
Take home message for growers: 1) surface water (rivers and ponds) are almost always contaminated with Phytophthora and Pythium species, 2) water can be tested using leaf baiting to determine if Phytophthora is present https://youtu.be/SJx7gzXyXoM 3) water should be disinfested before use in irrigation.
Poster IUFRO Redekar et al (724 KB)
19 Mar 2018
Slow Sand Filters
Pitton, B.J.L., Oki, L.R. (University of California Davis), White, S.A (Clemson University)
Slow sand filters (SSF) can provide high-quality water from untreated sources like irrigation runoff. SSFs consist of a sand bed with about three feet of water above that flows through the sand via gravity. A microorganism community develops on the sand that has the ability to remove plant pathogens, including water molds, viruses, bacteria, and fungi. Flow rates are approximately six inches per hour so they can occupy a large area if sizable volumes of water need to be treated. However, SSFs are simple to install and are fairly cheap to operate compared to other treatment technologies.