Surface and Ultrastructural Feeding Injury to Strawberry Leaves by the Twospotted Spider Mite

Abstract

Scanning and transmission electron microscopy were used to investigate damage to strawberry (Fragaria ×ananassa Duch.) leaves caused by twospotted spider mite (Tetranychus urticae Koch.). Mites damaged epidermal cells on the lower leaf surface, but did not damage major vascular elements of the leaf. Mite-damaged spongy and palisade parenchyma cells had coagulated protoplasts, with some cells devoid of cellular contents. Mesophyll cells adjacent to damaged regions showed no ultrastructural distortion or disruption of chloroplasts.