Location: Invasive Plant Research Laboratory
2012 Annual Report
Exotic invasive weeds from overseas pose a severe threat to native plants and ecosystems within the United States. The mission of USDA-ARS Invasive Plant Research Laboratory is to find environmentally friendly, biologically based strategies for long-term sustainable management of invasive weeds within the United States. Old World climbing fern, Lygodium microphyllum, is recognized as one of the three most damaging invasive weeds currently impacting natural ecosystems in Florida. The research described below supports the mission of the national program by furthering progress towards sustainable management of L. microphyllum. Populations of the brown lygodium moth, Neomusotima conspurcatalis, have survived into their fifth year at release sites in southeast Florida. As moth populations have fluctuated over recent years, there have been corresponding reciprocal changes in ground cover of L. microphyllum. When populations of the moth decline, reductions in feeding by caterpillars allow re-growth of L. microphyllum. When large populations of the moth are present at sites, defoliation by caterpillars causes considerable reduction in ground cover of L. microphyllum. The population at Jonathan Dickinson Park has proven especially resilient, having survived several frost and fire events. Several tree islands at Loxahatchee Wildlife Refuge harbor healthy populations, as does a cypress head along the perimeter of the park. The moth is spreading from these established populations, but apparently slowly. Colonization efforts with the lygodium moth, Austromusotima camptozonale, have been ongoing at several sites but thus far there is no evidence that persistent moth populations have established.