Abstract
A three-year survey was made to learn the seasonal occurrence of the potato cyst nematode, Globodera rostochiensis (Woll.) Mulvey & Stone, in a commercial potato field in Makkari Village, Hokkaido, Japan. Second stage larvae first appeared early in May and invaded into the potato roots as soon as they started growing. The number of nematodes within the roots reached a peak in the middle of June. Female adults were abundant on the roots during July and the cyst population increased in the soil following this period. Although the second stage larvae, which had decreased once in July after a peak in the middle of June, increased again in the soil in August, there was no appreciable indication of the occurrence of the second generation in the practical sense. Since no second stage larvae were isolated from the soil during March and April, it is considered that this nematode species does not overwinter as the form of second stage larvae free in the soil. Jap. J. Nematol. 7: 33-38 (1977)
