Morphological and molecular characterization of Cactodera milleri Graney & Bird, 1990 from Colorado and Minnesota

The genus Cactodera,has fifteen known species. Cactodera milleri was originally described infecting the roots of common lambsquarter (Chenopodium album) in Michigan. Chenopodium quinoa is a known host for C. milleri since 1990 when Graney and Bird included it in the host range study of this species. In 2019, C. milleri cysts were recovered from soil samples collected from a Chenopodium quinoa field, located in Mosca, Alamosa, county, Colorado, USA. A moderate number of lemon shaped cysts and juveniles were recovered from the affected quinoa plants. Same species was also recovered and identified from samples submitted over the years by the Minnesota Department of Agriculture as part of the Animal and Plant Health Inspection Service (APHIS) efforts to survey states for the presence of Pale Potato Cyst Nematode. The cysts and juveniles (J2) were recovered from soil samples through sieving and Baermann funnel extraction. The nematode species was identified by both morphological and molecular means as Cactodera milleri. To our knowledge this represents the first report of Cactodera milleri from Colorado and Minnesota.