Vol. 112 (1999): Proceedings of the Florida State Horticultural Society
Garden And Landscape

Phytophthora Bud-Rot of Palms in South Florida

J. F. Garofalo
University of Florida/Miami-Dade Cooperative Extension Service Homestead, FL 33030-2309
R. T. McMillan, Jr.
Tropical Research and Education Center 18905 SW280 ST Homestead, FL 33030

Published 1999-12-01

Abstract

Phytophthora bud rot is one of the more common diseases encountered in palms in wet tropical climates. In Florida more than 30 palm species are known to be susceptible, in addition to more than 30 non-palm species. The causal organism is Phytophthora palmivora, a soil-borne fungus in the watermold group. Synonyms include P. faberi and P. theobromae. It occurs naturally in South Florida, and can be spread in soil, on gardening tools and equipment, on plants, and probably in storm water. The symptoms, in order of occurrence, include 1. the bud only falls over, 2. the bud has a foul odor, 3. the spearleaf rots at the base, and 4. is easy to pull out, 5. the oldest fronds look OK, even after the bud has rotted, 6. the oldest fronds turn yellow, then brown, then collapse, and finally, 7. they fall off on their own. If these symptoms are noticed, specimens should be brought to a Plant Disease Diagnostic Clinic for confirmation of the cause. Symptomatic palms probably cannot be saved, but adjacent asymptomatic palms can be treated with Aliette, Banrot, or Subdue as directed on the label, and have a good chance of surviving.