First report of the hop cyst nematode Heterodera humuli from common nettle Urtica dioica in Turkey.
Cyst nematodes (Heterodera spp.) are one of the most important groups of plant parasitic nematodes in many countries throughout the world. The hop cyst nematode Heterodera humuli, the most common plant parasitic nematode found on hops (Humulus lupulus), was reported from Russia, Australia, the USA, Canada, New Zealand, South Africa, and several European countries (England, Belgium, Germany, Italy, Spain, Greece, and the Czech Republic). However, it has not been found in Turkey. The host range of this nematode was noted to be predominantly in the Urticaceae family and includes hops and Urtica dioica (common nettle); both plants are widespread in Turkey. Hops have been commercially cultivated in Bilecik city (Marmara Region) since 1965, and common nettle is used by people as an herbal medicine and food. In 2017, we randomly surveyed a naturally occurring common nettle growing area in Ordu province located in the Black Sea Region of Turkey. Cyst-forming nematodes were found on the roots of nettle. Cysts and infective second-stage juveniles (IJ2s) were collected from the infested roots and soil. Based on morphometric and molecular studies, the causal agent was identified as Heterodera humuli. This detection represents a new record of Heterodera humuli in Turkey.