Distribution of Xylella fastidiosa in Oaks in Florida and Its Association with Growth Decline in Quercus laevis

A survey of more than 200 trees has documented the widespread occurrence of Xylella fastidiosa in Florida oak populations. The pathogen was detected readily via enzyme-linked immunosorbent assay in oaks exhibiting decline or leaf scorch symptoms and was infrequently detected in asymptomatic trees. It was also associated with reduced growth in Quercus laevis as measured by current-year shoot length. The occurrence of X. fastidiosa in Q. laevis and the evidence for its occurrence in Q. incana represent first reports for these oak hosts. The role of X. fastidiosa in oak decline scenarios deserves further attention.

Individual Tree Treatments Using Herbicides for Control of Turkey Oak

Dicamba (Banvel® CST), 2,4-D (DMA® 4), triclopyr (Garlon® 3A), glyphosate (Roundup®), 2,4-D + picloram (Tordon® RTU), hexazinone (Velpar® L), dichlorprop (Weedone® 2,4 DP) and hexazinone (Velpar® Gridball®) were tested as individual tree treatments on turkey oak (Quercus laevis Walt.) trees ranging from 3 to 16 inches in dbh and 10 to 70 feet in height. Treatments were applied in June 1982 according to manufacturers recommendations. After two growing seasons, significant refoliation was observed on trees treated with Velpar® Gridball®, Weedone® 2,4-DP and Banvel® CST. Garlon® 3A, DMA® 4 and Velpar® L were the most successful treatments for control of turkey oak. South. J. Appl. For. 10:131-33, Aug. 1986.