The USDA Animal and Plant Health Inspection Service’s (APHIS) Plant Protection and Quarantine (PPQ) has prohibited the importation of Lygodium microphyllum, the Old World climbing fern. This action is necessary because APHIS has determined that this climbing fern species is a harmful, noxious weed that poses a serious environmental and economic threat to the United States. Recently, APHIS has also learned of commercial interest in importing Lygodium microphyllum as cut flower greenery. This restriction applies to any parts capable of propagation including nursery stock, the spores, or the leaves (fronds) of L. microphyllum that can contain the reproductive structures filled with spores. These spores may be windblown, spreading the plant into uninfested areas.
Lygodium microphyllum occurs in Florida where it is damaging habitats for federally-listed threatened and endangered species in the Everglades National Park, National Wildlife Refuges, and other conservation areas. Old World climbing fern climbs into trees and shades out native vegetation in hundreds of acres in east-central Florida. Dense growth of the plant can also be a fire hazard, frequently enabling small ground fires to reach into tree canopies where it can kill growing branches. Lygodium microphyllum is a Florida State noxious weed, subject to control. Areas of the United States at risk from infestation by L. microphyllum include the uninfested areas of Florida, and coastal regions of Texas, Louisiana, Alabama, and Mississippi.
Under IPPC standards, Lygodium microphyllum is considered to be a pest that is present (localized in Florida) and subject to official control in the United States