SPATIAL-DISTRIBUTION OF PINK WAX SCALE, CEROPLASTES RUBENS MASKELL (HEMIPTERA, COCCIDAE), ON UMBRELLA TREES IN SOUTH-EASTERN QUEENSLAND - THE PATTERN OF OUTBREAKS

The spatial pattern of outbreaks of pink wax scale, Ceroplastes rubens Maskell, within and among umbrella trees, Schefflera actinophylla (En dl.), in southeastern Queensland was investigated. Pink wax scale was common on S. actinophylla, with approximately 84% of trees positive fo r scale and 14% of bees recording outbreak densities exceeding 0.4 adu lts per leaflet. Highly aggregated distributions of C. rubens occur wi thin and among umbrella trees. Clumped distributions within trees appe ar to result from variable birth and death rates and limited movement of first instar crawlers. The patchy distribution of pink wax scale am ong trees is probably a consequence of variation in dispersal success of scale, host and environmental suitability for establishment and rat es of biological control. Pink wax scale was more prevalent on trees i n roadside positions and in exposed situations, indicating that such t rees are more suitable and/or susceptible to scale colonisation.