A Comparative Histological Study of the Effects of Feeding by Nymphs of Four Psyllid Species on the Leaves of Eucalypts

The feeding sites of four species of psyllids were compared histologically. Cardiaspina albitextura, Creiis costatus and Lasiopsylla rotundipennis draw their food from cells of the sheathing parenchyma and pholem tissue of small vascular bundles. Glycaspis sp. feeds from the pholem cells of much larger bundles. Obvious damage to leaf tissue was associated only with C. albitextura and Glycaspis sp., and was much more severe for the former. The damaged tissue resembled that of naturally‐senescing leaves. This suggests that these two species are able to augment the food available from vascular bundles by causing a breakdown of palisade mesophyll.