抄録
Seasonal population prevalence of aphids was investigated in a potato field at Hitsujigaoka, Sapporo, Japan (43°0'N, 141°25'E) from late May to late September in 1991 - 1993. The aphid species surveyed on potato were Myzus persicae (SULZER), Aulacorthum solani (KALTENBACH), Macrosiphum euphorbiae (THOMAS) and Aphis gossypii GLOVER. Immigration of A. solani and M. persicae started in late May or early June, and that of m. euphorbiae and A. gossypii in mid-June, and mid- to late June, respectively. A single peak of apterae in A. solani and M. persicae appeared in mid-June or early July. While some peaks of them in M. euphorbiae and A. gossypii appeared between late June and late August. Seasonal prevalence of alatae and alatoid nymphs showed that M. euphorbiae tended to produce more alatae than the other three species, and that only A. gossypii frequently immigrated into the potato field. Since few alatae were usually produced in the four aphid species in the field, emigration from the field must have been rare.
