First Report of Infection of Lygodium microphyllum by Puccinia lygodii, a Potential Biocontrol Agent of an Invasive Fern in Florida

Lygodium microphyllum (Cav.) R.Br. (Old World climbing fern), in the family Schizaeaceae, is one of the most invasive (Category I in Florida) weeds in Florida. It has invaded more than 50,000 ha of wetlands and moist habitats in southern Florida and is rapidly spreading in new areas of the Everglades (3). The search and evaluation of biocontrol agents for this fern is currently in progress. Puccinia lygodii (Har.) Arth. (Uredinales) (1), previously recorded on L. volubile Sw. and L. venustum Sw. in South America (2), attacks foliage and severely damages L. japonicum Thunb. (Japanese climbing fern) vines in northern and central Florida (4). We hypothesized that since L. japonicum occurred mainly in northern and central Florida, P. lygodii did not have opportunity to interact with L. microphyllum, which primarily occurs in southern Florida. Therefore, we used two inoculation methods to test the possible pathogenicity of P. lygodii on the new host, L. microphyllum. Method-I was designed to imitate a seminatu...