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Phlox subulata (moss phlox)
Photograph courtesy of Pawel Michalik, Wikipedia [accessed 1 June 2010]

Plant Pathology Section

Compiled by Robert M. Leahy

This section provides plant disease diagnostic services and conducts a citrus germplasm introduction program. The agency-wide goal of protecting Florida agriculture very often begins with accurate diagnosis of plant problems. Disease management recommendations are offered where appropriate and available. Our plant pathologists are dedicated to keeping informed about plant diseases outside Florida in order to be prepared for potential introductions of new pathogens.

Guignardia citricarpa Kiely (citrus black spot), a North America record, was detected on Citrus sinensis (sweet orange) during a Citrus Health Response Program - Multipest Survey (CHRP-MPS) in the Immokalee area. Conventional and advanced diagnostic laboratory techniques confirmed the identity of the pathogen. This marks the first report of this fungal pathogen in North America, and constitutes a major jump in the geographical range of the pathogen. Please see the DPI Pest Alert . (Collier County; P2010-34844; Maria D. Olvera and Bobbie L. Seay; 8 March 2010.)

Peronospora phlogina (downy mildew), a new State record, was found in a nursery on Phlox subulata (moss phlox). This pathogen has been previously reported from cooler climates in the Central and Western United States. Cool, wet conditions are thought to encourage infection and promote development of the wind-borne spores. This downy mildew infects several genera in the Polemoniaceae including Gilia, but not Ipomopsis rubra (formerly G. rubra). It has never been reported on the popular annual phlox (P. drummondii), often used as a cool season bedding plant and wildflower in Florida, nor on any of the other ten or so species of Phlox found in Florida. (Alachua County; P2010-35479; M. Janie Echols and Cheryl A. Jones; 24 March 2010.) (Dr. Timothy S. Schubert.)

Plant Pathology Sample Report

Following is a table with entries for records of new hosts or new geographical areas for samples identified in the current volume's time period as well as samples of special interest. The tables are organized alphabetically by plant host.