Location: Invasive Plant Research Laboratory
Project Number: 6032-22000-013-127-R
Project Type: Reimbursable Cooperative Agreement
Start Date: Oct 1, 2023
End Date: Sep 30, 2025
Objective:
Old World climbing fern (Lygodium microphyllum) is arguably Florida’s worst natural area invasive plant. The perennial fern climbs vegetation and shades out native plant communities, including tree islands and cypress domes that comprise the Greater Everglades ecosystem and other conservation lands managed by the South Florida Water Management District (District). Due to the remote nature of many Old World climbing fern (OWCF) patches, mechanical control is not feasible, and application of herbicides is often expensive in difficult to access areas. A biological control program, which employs insects that only attack the invasive plant, was initiated with the expectation that introduced natural enemies would complement existing control efforts.
1) Maintain colonies of OWCF biological control agents in quarantine
2) Complete testing of the defoliating sawfly Neostrombocerus albicomus with Caribbean species of Lygodium and complete host-range testing and prepare TAG petition (if sawfly is unable to sustain a population on non-target species).
3) Complete host specificity tests, multigenerational testing, and processing of cold tolerance testing data of the defoliating moth, Lygomusotima stria and prepare TAG petition if results indicate limited or no risk to non-target Lygodium species
4) Survey for and collect OWCF herbivores, including new species, in Queensland (Cape York), the Northern Territory, Western Australia, Asia, and potentially New Caledonia
5) Characterize the genetic profiles of OWCF collections in the native range to identify the best matches to the invasive Florida lines
Approach:
Old World climbing fern (OWCF) biological control involves the discovery of natural enemies and pathogens in the plant’s native range, their import and study in quarantine conditions, and ultimately the release of safe (host-specific) herbivores into invaded regions of Florida. The United States Department of Agriculture (USDA), Agricultural Research Service (ARS), Invasive Plant Research Laboratory (IPRL) in Fort Lauderdale, Florida, in cooperation with overseas collaborators have conducted surveys in Asia, Australia and the Pacific to identify host-specific arthropod herbivores of OWCF that could potentially be introduced to southern Florida to help control OWCF (Goolsby et al. 2003). To date, scientists have collected more than 20 species of insects and mites that feed on OWCF. Three species underwent host-range testing and were approved for release by USDA’s Animal Plant Health and Inspection Service (APHIS). Numerous releases of the (white) defoliating moth, Austromusotima camptozonale were made in Florida, but it failed to establish for unknown reasons. However, scientists have successfully introduced another defoliator, the brown lygodium moth, Neomusotima conspurcatalis, and the leaf-galling mite Floracarus perrepae from Australia. Testing of another defoliating species, Callopistria exotica from Hong Kong was completed and a petition for field releases was recently granted (Sep 7, 2023). Finally, testing of a defoliating sawfly, Neostrombocerus albicomus from Thailand, was previously completed, however additional data were requested as it fed on several Caribbean species of Lygodium. Additional testing is underway at the IPRL and preliminary results suggest this insect is promising and safe for release.
