Abstract

The pattern of cell punctures in the electrical penetration graph was studied from the start of a probe leading to the first phloem phase by the aphid Sitobion fragariae (Walker) (Sternorrhyncha: Aphididae) on two cultivars of the wheat, Triticum aestivum L., differing in hydroxamic acid concentration. In addition, the spatial arrangement of cells in the leaf of the host plant was histologically observed and the number of cells between the epidermis and phloem counted. The results suggest a feeding deterrent effect of hydroxamic acids and a constant stylet puncturing activity into plant cells.