Morphology of the Nettle Cyst Nematode Heterodera Urticae Cooper, 1955

Heterodera urticae Cooper, 1955, widespread in Northern Ireland on nettles (Urtica dioica L.), is described and accepted as a valid species. It resembles related species of the goettingiana group in that the mature cysts possess a vulval cone which is ambifenestrated and without conspicuous bullae. The cysts are small, averaging 492 X 435 μ; the egg-sac is small and never contains extruded eggs; and the larvae are long, averaging 541 μ, with a mean stylet length of 27 μ and a clear tail/stylet length ratio averaging 1.1. The gubernaculum has a beaded margin — such ornamentation has not been previously reported for any Heterodera species.