Two New Species of Cyst Nematode, Heterodera Mani N. Sp. and H. Iri N. Sp., From Northern Ireland

Abstract

Two new species of cyst nematode occurring on grasses in Northern Ireland are described and illustrated. Both, having bifenestrate bullate cysts, belong to the avenae species-group. H. mani n. sp. infests Lolium, Dactylis and Festuca species. It differs from H. avenae Woll., 1924 in that the larvae have deeply concave stylet-knobs and four lines in the lateral field; the more rounded females have shorter stylet-knobs; the males have smaller heads and longer spicules and the cysts are more rounded and possess a distinct underbridge. H. iri n. sp. parasitizes Agrostis sp. and differs from both H. avenae and H. mani in that the larvae possess exceptionally long tails (true-tail and clear-tail averaging 94 μ and 62 μ respectively) ; the cysts are more spheroidal, much lighter in colour, have a thin matt-white subcrystalline layer and a strong underbridge. Unlike H. avenae neither new species attacks cereals.