On the Pathogenicity of Heterodera schachtii to Potatoes and Mangolds

Abstract

In 1925, Morgan, in recording field observations on Heterodera schachtii in the Kirton district, pointed out that cysts were frequently as abundant in certain areas of infected fields where the yield was satisfactory, as in “bad patches” where the plants showed every manifestation of eelworm disease, and where the crop was a failure. In a further publication (1926) he again emphasized the lack of correlation between cyst content of the soil and the incidence of “potato-sickness.” One field on which detailed observations were carried out, although the worst case of eelworm infestation examined in the district, was found to give a satisfactory crop—average yield eight tons ware per acre—after only a four year rotation. In summing up these observations, Morgan says: “While it is not suggested that the eelworm had no influence on the yield in this instance, the success of the crop in spite of the pest lends support to the view that the problem is primarily one of obtaining more suitable conditions for plant growth by more judicious manuring and a system of rotation.”