Biology and control of psyllids, and the possible causes for defoliation of Eucalyptus camaldulensis Dehnh. (river red gum) in south-eastern Australia—a review

Summary

Psyllids are one of the most devastating insect pest groups in Australia, affecting both native forests and eucalypt plantations. They feed on a wide variety of eucalypt host species, with some psyllid species restricted to a single eucalypt host species or to a group of closely related species. Predominant amongst eucalypt species attacked by psyllids is Eucalyptus camaldulensis Dehnh., an important tree species for a variety of reasons including the insect and decay resistance of the timber, its role in reducing water table levels and minimising erosion along streams and rivers, its adaption to soils with significant salt content, and its importance as a habitat for native wildlife. In recent years it has become a candidate species for plantation forestry, especially in the northern irrigation areas of Victoria. This paper briefly examines the biology of psyllids, covering their identification, description and life-cycles, and providing a brief history of major psyllid outbreaks in Australia. The potential for attack, levels of defoliation and subsequent impact on tree growth and tree health are also examined. Options for control of psyllids are discussed to enable landholders and forest plantation managers to make more informed decisions on ways of dealing with outbreaks on eucalypts, particulary E. camaldulensis.