Observations on the feeding of the virus vector Orosius argentatus (Evans), and comparisons with certain other jassids.

Abstract

Examination of feeding tracks of several species of jassids in plant petioles shows that each species produces characteristic stylet sheaths. Most species feed in both parenchyma and vascular bundles and they exhibit varying degrees of preference for phloem tissue. An attempt to confirm published observations on a pH gradient towards the phloem failed to reveal such a gradient in many of the plants examined; in fact, it has been demonstrated that no such gradient is required to explain the feeding behaviour of the jassids studied. It is concluded that they find .the tissues upon which they feed by random probing with the stylets.