AIR PARTICULATES ASSOCIATED WITH THE ASH WHITEFLY

Unusual air particulates are linked to recent heavy infestations of th e ash whitefly in California using high-performance liquid chromatogra phy, scanning electron microscopy, optical and infra-red microscopy, i on chromatography and X-ray fluorescence spectrometry. The unusual par ticles apparently are microdroplets of ash whitefly honeydew. Most of the suspended honeydew is in microdroplets with diameters between abou t two and twenty microns. The microdroplets were found to contain subs tantial amounts of sugars, primarily the oligosaccharides stachyose an d raffinose. They also contain about 1 percent potassium, mainly as K. The unusual microdroplets have been found in samples of air particul ates taken in many areas of California after 1988. Using a receptor mo del, the suspended honeydew was calculated to add as much as 40 microg m/M3 to PM10 mass. The highest levels of suspended honeydew occurred b etween late August and early November.