**AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** THE HOP CYST NEMATODE (HCN), HETERODERA HUMULI, IS A THREAT TO UNITED STATES HOP PRODUCTION, WHICH IS CURRENTLY THE TOP PRODUCER OF HOPS WORLDWIDE. PRIOR STUDIES HAVE FOUND THAT THE HOP CYST NEMATODE CAUSES SEVERE PLANT STRESS, NUTRITIONAL DEFICIENCIES, AND MECHANICAL INJURY LEAVING THE PLANT SUSCEPTIBLE TO SECONDARY INFECTIONS. IT IS ALSO ASSOCIATED WITH CAUSING YIELD LOSSES OF 38% PER STRING OR PLANT DEATH IN SOME CASES (HAFEZ ET AL., 1999; HAY & PETHYBRIDGE, 2003; MENDE & MCNAMARA, 1995). OUR RECENT PRELIMINARY FINDINGS DESCRIBED WITHIN THIS PROPOSAL INDICATE THAT THE HOP CYST NEMATODE IS BECOMING OR HAS BECOME WIDESPREAD THROUGHOUT THE NATION'S TOP-PRODUCING REGIONS (DARLING ET AL., 2020; DARLING ET AL. 2021 UNPUBLISHED) AND IS POSING A RISK TO YIELD. THEREFORE, IMMEDIATE ACTION SHOULD BE TAKEN TO ADDRESS THIS ISSUE. CURRENTLY, THERE ARE NO KNOWN EFFECTIVE FORMS OF MANAGEMENT FOR HOP GROWERS WITH HOP CYST NEMATODE, SO POSITIVE SAMPLES LEAVE GROWERS WITH LIMITED OPTIONS. THE KEY FOR PREVENTING THIS AGGRESSIVE PEST OF HOP PRODUCTION FROM HINDERING YIELD AND CORRESPONDING ECONOMIC LOSS IS TO DETERMINE DISTRIBUTION WITHIN KEY REGIONS, DEVELOP EFFECTIVE AVOIDANCE/MITIGATION STRATEGIES, AND ENSURE THAT THIS INFORMATION IS WIDELY- AND EASILY- ACCESSIBLE TO AMERICAN HOP GROWERS

Michigan State University, East Lansing MI

Investigators