In 2018, Heterodera pratensis was detected in Michigan in a serendipitous sequencingevent; Heterodera cysts were identified in a soil sample from a golf course in St. Clair County with morphological data matching that of published measurements and confirmed by the USDAl aboratory in Beltsville, MD. This was believed to be the first detection of this nematode in North America.To better understand the life cycle of H. pratensis, Poa annua and Agrostis stoloniferawere inoculated with second stage juveniles, and plants were destructively sampled 1-155 dayspost inoculation. Field data were also collected from two greens on an infected golf course in Cheboygan, Michigan. For two years, the population of H. pratensis and temperature information were monitored. The total life cycle, from inoculation to cyst formation, in the growth chamber was 70 days on creeping bentgrass and 71 days on annual bluegrass, with nosecondary egg hatch, suggesting only a single generation annually. In the field study, J2s had amajor hatch in the spring and adults were observed between 60-90 days.To understand the host range and possible threats to small grain producers and othe rturfgrasses, 17 grass species were screened. Nine of 17 were considered good hosts, 4 were poor hosts, and 4 were non-hosts, based on the finial population-initial population reproduction ratio(Pf/Pi). H. pratensis developed on wheat and barley, which were not previously noted as hosts.
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