Hemicycliophora potteri n. sp. (Tylenchida: Hemicycliophoridae) infesting highbush blueberry (Vaccinium corymbosum) in Ontario, Canada

Summary Highbush blueberry is a blueberry species native to North America and is a food crop of significant economic importance for Canada. Plant-parasitic nematodes are known to infest this crop. Species of Hemicycliophora , commonly known as sheath nematodes, are obligatory plant-parasites, and some cause diseases on a wide range of crops. A population of Hemicycliophora of high number was found in highbush blueberry fields in Norfolk and Middlesex counties of southwestern Ontario. Following through morphological and molecular studies, this population was determined a new species as Hemicycliophora potteri n. sp. This species is characterised by its outer sheath adpressed fitting to the body, lateral fields with diagonal connections of transverse striae, amphid apertures covered by lateral plates, lip region slightly set-off with four annuli; excretory pore anterior to the base of the pharynx, stylet knob cavity moderate, vulva lips modified, tail tapering gradually and more abruptly towards the last one-third, and no males were found. Molecularly, the 18S, and 28S ribosomal DNA sequences are most similar to those of H. thienemanni , H. similis , H. gracilis , and a few unidentified species. A dichotomous key for the diagnostic of the species of Hemicycliophora in Canada was presented. To the best of our knowledge, Hemicycliophora potteri n. sp. is the first recorded species of the genus to be named and fully described from highbush blueberry.