A Technical Report from The Bartlett Tree Research Laboratories
For several years, arborists and homeowners throughout California have observed symptoms of general decline in hedges, screens, and specimen plantings of Pittosporum undulatum, or Victorian box. Many potential causes or combinations of factors have been suggested, but a specific pathogen, insect pest, or environmental factor has not been proven. Recently, extensive sampling and analysis of declining and healthy plants has led to theorizing that a scale insect and a canker-causing fungus are playing a significant role in the decline.