Insect Herbivory in a River Red Gum (Eucalyptus camaldulensis Dehnh.) Forest in Southern New South Wales

The influence of insect herbivory on tree growth was examined in a river red gum (Eucalyptus camaldulensis) forest in southern New South Wales. Mature E. camaldulensis trees treated with the systemic insecticide monocrotophos lost an average of 13.9%± 1.6 of potential leaf area from current season's foliage compared with 22.3%± 1.6 from untreated trees. the most common form of damage was caused by leaf‐chewing insects. Leaf tissue lost by sap‐sucking, leafmining or galling insects was minimal. A total of 49 species of phytophagous insects were collected from the E. camaldulensis canopies. the insecticide‐treated trees had significantly higher rate of diameter increment (2.9 cm ± 1.1 vs. 0.7 cm ± 0.1). They also possessed healthier crowns and significantly larger leaf length/width ratios. the insecticide treatment had no significant effect on potential area per leaf or mean specific mass of the sampled foliage. the level of insect herbivory in nearby saplings was not significantly different to that of the mature trees.