On Heterodera cruciferae n.sp. of Brassicas, and on a Heterodera Strain infecting Clover and Dock

Abstract

Heterodera cruciferae n. sp., parasitic upon Brassicas and other Cruciferous plants, is described and compared with H. schachtii, the sugar beet eelworm.The new species differs from the sugar beet eelworm in its host range, in the reaction of the larvae to root excretions of sugar beet and in the time of hatching of the larvae. The cysts are somewhat shorter and rounder than in the sugar beet eelworm and differ in having attached to the vulva a mass of jelly-like substance containing eggs and sometimes one or two males. The larvae are shorter than in H. schachtii. The males are similar but tend to be smaller and with shorter stylets.The results of infection experiments with cysts from the roots of dock and of clovers indicate that these cysts are of the same race, and are probably a biological strain of the sugar beet eelworm H. schachtii.