Vol. 119 (2006): Proceedings of the Florida State Horticultural Society
Ornamental, Garden & Landscape

Dynamics of powdery mildew in a homogenous urban sand live oak (Quercus geminata ) forest

Robert J. Northrop
University of Florida

Published 2006-12-01

Keywords

  • Quercus geminata,
  • oak mildew,
  • urban ecology

Abstract

Powdery mildew fungi are a family of obligate parasites of horticultural plants, agricultural crops, and trees. These fungi may retard the growth of young plants and may kill tree seedlings. While the evidence is inconclusive, recurring attacks of powdery mildew, in combination with other pathogens or herbivory by mammals and insects, are thought to even cause older trees to die. A recent outbreak of the disease associated with sand live oak (Quercus geminata) is the focus of an ongoing investigation in the Tampa Bay region. A review of the literature suggests that this occurrence is unprecedented in its intensity and geographic extent. It is suspect in the loss of mature trees within the region, and demonstrates how the lack of urban forest diversity can lead to uncommon disease and insect infestation patterns.