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Mikania micrantha (climbing hempweed, mile-a-minute vine)
Photograph courtesy of Patti J. Anderson, DPI

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.

Septoria mikania-micranthae (leaf spot), a new Northern Hemisphere record, was previously known only from Brazil and is considered a potential biocontrol pathogen. It was found on the invasive vine, Mikania micrantha, a noxious weed that was recently detected in Miami-Dade County, also for the first time in this country. The sexual stage of this pathogen (Mycosphaerella mikania-micranthae) has not been detected on Florida material so far. There are only two Septoria spp. on Mikania now reported in the United States, and this one is the only Septoria on Mikania reported from Florida. (Miami-Dade County; P2010-33451; Douglas A. Restrom Gaskill, Shi-Yih Edward Hung, Warren J. "Jim" Dowling, Levina D. Hancock, Charles D. "David" Wolfe; 14 January 2010.)

Cercospora mikaniacola (leaf spot), a new Host record, also found on Mikania micrantha, has been previously found on other species of Mikania in Florida. It is also known from Brazil, India and elsewhere around the world where this weed is a problem. Though it is an aggressive pathogen that sporulates abundantly on the host, it would be difficult to develop as a biocontrol agent because it grows so slowly in culture. (Miami-Dade County; P2010-33064; Carrie L. Karppe, Jose L. Llanos, Rosamaria M. Quinones, Warren J. "Jim" Dowling, Brian D. Saunders; 14 January 2010.)

Corniculariella sp. (fungus), a new State record, found on Prunus persica, is probably an undescribed anamorph of a discomycete fungus, Durandiella, that is saprophytic with some host specificity on twigs of many different hosts. Although the peach trees from which this fungus was recovered are experiencing premature decline and death, this fungus is probably not a contributing agent to the syndrome. (Alachua County; P2010-34211; homeowner; 3 February 2010.)

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.