Author
Briana , M , Foster
University of Florida
Fort Pierce, United States
Forrest A Dray
allen.dray@usda.gov
USDA Agricultural Research Service
Fort Lauderdale
Coauthors
Jorge Leidi, USDA Agricultural Research Service, Fort Lauderdale, United States
Briana M Foster, University of Florida, Fort Pierce, United States
Dale A Halbritter, USDA Agricultural Research Service, Fort Lauderdale, United States
Min B Rayamajhi, USDA Agricultural Research Service, Fort Lauderdale, United States
Abstract
Dioscorea bulbifera (air potato) is an invasive vine that smothers and outcompetes native plants. It colonizes new sites by means of tuber-like reproductive structures called bulbils which develop in the leaf axils. Bulbils appear on air potato vines in late summer and dehisce by winter. Bulbils produce new vines and persistent underground tubers during the following spring. Two biological control agents from the beetle genus Lilioceris have been introduced from the vine’s native range to combat its spread. The air potato leaf beetle (APLB), L. cheni, was first released in Florida in late 2011 and the air potato bulbil beetle (APBB), L. egena, in late 2021. APLB adults and larvae feed on air potato foliage where adults also oviposit. APBB adults and larvae feed by burrowing into the bulbils, with adults ovipositing on the exterior of the bulbil at the soil surface or within adult feeding tunnels inside the bulbil. Both species pupate in the soil, though APBB occasionally pupates inside bulbils. Differences in feeding habits by the two species suggests synergistic damaging of the vine. We examined this by setting up twelve cages with four treatments (three cages each) containing either no beetles, APLB, APBB, or both APLB and APBB. Beetles remained in cages for two months before harvesting the experiment. Preliminary analysis shows mixed results in terms of foliar damage and bulbil damage. We discuss the implications of this outcome in terms of air potato management efforts.
Keywords
Dioscorea bulbifera
Lilioceris egena
Lilioceris cheni
biological control
agent synergy
Highlights
Two Lilioceris beetles have been released in Florida to combat the invasive air potato vine.
One beetle preferentially attacks foliage, the other bulbils (vegetative propagules).
Impacts, while complementary, may not be truly synergistic nor additive.