Biocontrol of Lygodium microphyllum
Aquatic Weed Control Short Course 7 May 2014 Melissa C. Smith Ellen C. Lake Paul D. Pratt USDA-ARS Invasive Plant Research Lab Fort Lauderdale, Florida Lygodium microphyllum in South Florida…and beyond Lygodium in Conservation Areas
Flatford Swamp A.R.M. Loxahatchee Everglades National Park NWR Greenswamp Wilderness Preserve L. microphyllum reproduction Propagule pressure: Sori
• Each sorus has ~ 215 spores • Each fertile leaflet has ~ 133 sori • 215 X 133 = 28,500 spores per fertile leaflet (Volin et al. 2004)
Lygodium biological control: Moths that were, moths that are, and some moths that Austromusotima camptozonale have not yet come to pass (and a mite)
Neomusotima conspurcatalis
Lygomusotima stria Neomusotima conspurcatalis (Lepidoptera: Crambidae) Neomusotima releases 2008 - 2009 Neomusotima range 2012 - 2014 Neomusotima in the field Neomusotima in the field Neomusotima in the field Neomusotima research
Feeding preference • Do N. conspurcatalis larvae preferentially feed on fertile fronds? • Effects of fertile frond feeding on spore germination • Effects of fertile frond feeding on larval development time
Neomusotima research
Feeding preference • 1st and 2nd Instar Larvae preferentially feed on fertile fronds in choice tests (p<0.02, Hotelling’s T2).
Neomusotima research
Spore germination • Passage through the gut of the caterpillar only resulted in 2 prothalli Neomusotima research
Development time • Fertile frond feeding did not significantly affect larval development time or successful emergence to adult. • Did not measure “downstream” effects in adults or larval size.
Neomusotima research
To be completed: • Oviposition preference • Fecundity effects in adults Integrated weed management
• Control • Neomusotima only • Herbicide only • Neomusotima and herbicide
Floracarus perrepae (Eriophyidae)
• Transfers of galled material 2008 – 2010 • Very low establishment success measured in 2011 • Thought to be haplotype specific? • Does wet or dry season release timing determine establishment? Freeman et al. 2005 F. perrepae damage
• Australia: Goolsby et al. (2004) • Reduced aboveground biomass by 49% • Reduced belowground biomass by 35% • In Florida: • Reduction of formation of fertile fronds? • Are mite and moth damage synergistic? F. perrepae releases 2008 F. perrepae range 2013
Lygodium and CERP
• Mass rearing and release of N. conspurcatalis and F. perrepae • Follow up to determine “success” (establishment, impact, dispersal) • Priorities given to natural areas Future directions
• Determine the relative impacts of the moth alone, the mite alone, and the two together • Build occupancy models to predict “patches” where moths could occupy and focus releases • More thorough investigation of haplotype mismatch – genotyping of introduced and native range Lygodium and F. perrepae Acknowledgments
Southwest Florida Water Management District