An outbreak of the gum-leaf skeletoniser, Uraba lugens Walker, in river red gum forest near Barmah.  J. A. Harris, F. G. Neumann and B. Ward.  June 1977.  15 pp. (unpubl.)

SUMMARY

About 30,000 ha of inundated River red gum forest in the Murray Valley Region of northern Victoria near Barmah was lightly to severely defoliated by larvae of the gum leaf skeletonizer, Uraba lugens Walker, during March and again in October/November 1975 when the annual rainfall was 144 mm higher than average. This outbreak was unexpected, as infestations were thought to occur only in dry forest and mostly in years below average rainfall. The trees regenerated their foliage during the subsequent summer, and this foliage has so far remained healthy. Flood waters seem effective in controlling the pest only if they occur between spring and mid-summer or between March and June, as during these periods the eggs, the early and final instar larvae and the pupae are located close to the forest floor. In general, larvae that reach the tree crowns prior to flooding seem immune from the lethal effects of flooding. Insecticidal control of the early larval stages of the pest is unattractive because of concern about undesirable side effects on aquatic organisms in the extensive water courses of the region.