On the Occurrence of Heterodera Cysts in Various Soils and on the Roots of Agrostis stolonifera L.

Abstract

During the microscopical examination of the debris collected by flotation from soil infected with the potato eelwormHeterodera schachtii Schmidt, the presence of small numbers of cysts unlike those typical of the potato strain has frequently been observed. The distinguishing characters of these cysts are their dark colour and their lemon-like shape. Similar cysts were seen by chance during observations on “clean” soil which was being used as a control to pot experiments with eelworm-infected soil. This “clean” soil had been obtained from a heap of top-spit material which had been removed from a field on Winches Farm known to have been under grass for at least twenty years, and probably longer.