Air Particulates Associated with the Ash Whitefly

Abstract

Unusual air particulates are linked to recent heavy infestations of the ash whitefly in California using high-performance liquid chromatography, scanning electron microscopy, optical and infrared microscopy, ion chromatography and X-ray fluorescence spectrometry. The unusual particles apparently are microdroplets of ash whitefly honeydew. Most of the suspended honeydew is in microdroplets with diameters between about two and twenty microns. The microdroplets were found to contain substantial amounts of sugars, primarily the oligosaccharides stachyose and raffinose. They also contain about 1 percent potassium, mainly as K⁺ The unusual microdroplets have been found in samples of air particulates taken in many areas of California after 1988.

Using a receptor model, the suspended honeydew was calculated to add as much as 40 microgm/M³ to PM₁₀ mass. The highest levels of suspended honeydew occurred between late August and early November.