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United States Department of Agriculture

Agricultural Research Service

Title: Responding to An Introduced Pathogen: Podsphaera Macularis (Hop Powdery Mildew) in the Pacific Northwest

Authors
item Mahaffee, Walter
item Thomas, Carla - FIELDWISE, INC
item Turechek, William - CORNELL UNIVERSITY
item Ocamb, Cynthia - OREGON STATE UNIVERSITY
item Nelson, Mark - WASHINGTON STATE UNIVERSI
item Fox, Alan - FOX WEATHER, LLC
item Gubler, Walter - UNIVERSITY CALIFORNIA

Submitted to: Plant Health Progress
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 28, 2003
Publication Date: November 13, 2003
Citation: Mahaffe, W.F., Thomas, C.S., Turechek, W.W., Ocamb, C.M., Nelson, M.E., Fox, A., Gubler, W.D. Responding to an Introduced Pathogen: Podosphaera macularis (Hop Powdery Mildew) in the Pacific Northwest. Online. Plant Health Progress doi:10.1094/PHP-2003-1113-07-RV.

Interpretive Summary: Hop Powdery mildew was introduced into the Pacific Northwest in 1996. An overview of the response of the research team to the introduction is presented. In addition, a list of considerations for handling future pathogen introductions is presented.

Technical Abstract: Abstract In 1996, hop powdery mildew Podosphaera macularis (formerly Sphaerotheca macularis) was found in the Yakima Valley, WA and subsequently spread to the growing regions in Oregon and Northern and Southern Idaho. To rapidly assist growers in reducing the cost associated with the preventive fungicide program, the Gubler/Thomas grape powdery mildew risk infection model was adapted for hops. In addition, field surveys were utilized to identify other management practices that impacted disease development. Weather networks were established and utilized to deliver daily regional maps indicating the risk index. These maps were posted to the web for daily access. Lessons learned from this experience will be useful in addressing future pathogen introductions.

Last Modified: 10/20/2014
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