Biological control ofLygodium microphyllum, Old World climbing fern: foreign exploration and host range testing

Authors: Lake, Ellen; PURCELL, MATTHEW - Commonwealth Scientific And Industrial Research Organisation (CSIRO); Mattison, Elizabeth

Submitted to: Florida Entomological Society Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 4/30/2019
Publication Date: N/A
Citation: N/A

Interpretive Summary: Lygodium microphyllum, Old World climbing fern, is a climbing fern native to Asia and Australia. It has established and is expanding its range in Florida where it is negatively impacting native flora and fauna. Three biological control agents have been approved for release and two have established on the weed in Florida. However, additional agents are needed to achieve desired levels of control. Exploration for arthropods feeding on L. microphyllum is ongoing in its native range, particularly in Australia and southeast Asia. Host-range testing is being conducted with two moths and a sawfly at the USDA ARS Invasive Plant Research Laboratory quarantine facility in Fort Lauderdale, FL. No-choice testing has been completed with the moth Lygomusotima stria (Lepidoptera: Crambidae). This moth can complete development on several lygodium species and multigeneration tests are ongoing to determine if it can form sustainable populations on these species. Cold-tolerance testing for L. stria indicates that it is unlikely to fully colonize Florida or overlap in range with the southernmost populations of the native species Lygodium palmatum. Herbaria records of L. palmatum are being compiled to map the range of this species for comparison to the projected range of L. stria. A sawfly, Neostrombocerus albicomus (Hymenoptera: Tenthredinidae), can reach outbreak densities on L. microphyllum in the native range. Multigeneration testing is ongoing with this insect and three lygodium species. The moth Callopistria exotica (Lepidoptera: Noctuidae) feeds very heavily on L. microphyllum foliage creating “fish-boning” damage. Rearing methods have been developed for C. exotica and host-range tests completed to date indicate that C. exotica is a lygodium specialist.

Technical Abstract: Lygodium microphyllum, Old World climbing fern, is expanding its range in Florida and negatively impacting native flora and fauna. Three biological control agents have been approved and two have established on the weed but additional agents are needed to achieve desired levels of control. Exploration for arthropods feeding on L. microphyllum is ongoing in its native range, particularly in Australia and southeast Asia. Host-range testing is in progress with two moths and a sawfly at the USDA ARS Invasive Plant Research Laboratory quarantine facility in Fort Lauderdale, FL. No-choice testing has been completed with the moth Lygomusotima stria (Lepidoptera: Crambidae). This moth can complete development on several lygodium species and multigeneration tests are ongoing. Cold-tolerance testing for L. stria indicates that this species is unlikely to fully colonize Florida or overlap in range with the southernmost populations of the native species Lygodium palmatum. Herbaria records of L. palmatum are being compiled to delineate the range of this species for comparison to CLIMEX mapping of the projected range of L. stria. A sawfly, Neostrombocerus albicomus (Hymenoptera: Tenthredinidae), can reach outbreak densities on L. microphyllum in the native range. Multigeneration testing is ongoing with this insect and three lygodium species. The moth Callopistria exotica (Lepidoptera: Noctuidae) feeds very heavily on L. microphyllum foliage creating “fish-boning” damage. Rearing methods have been developed for C. exotica and host-range tests completed to date indicate that C. exotica is a lygodium specialist.