Classical Biological Control of Air Potato Vine, Dioscorea bulbifera, Infestations in Florida

Authors: Rayamajhi, Min; Dray, F Allen

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 5/12/2022
Publication Date: 6/15/2022
Citation: Rayamajhi, M.B., Dray Jr, F.A. 2022. Classical Biological Control of Air Potato Vine, Dioscorea bulbifera, Infestations in Florida. Book Chapter. 288-299.

Interpretive Summary: The air potato vine was introduced to the United States over two centuries ago and has become one of the most serious exotic invasive weeds in Florida. It vigorously invades both disturbed and undisturbed habitats under public and private ownership across Florida, southern Georgia, Alabama, Mississippi, Louisiana, and Texas. Research shows the vine grows up to 25 cm (10 inches) per day and branches profusely. These attributes enable air potato to climb up and over other vegetation, smothering trees, shrubs, and other plants. As it grows it produces numerous aerial tubers (“bulbils”), which fall to the ground when the vines die back in winter. The bulbils and underground tubers sprout in spring and repeat the seasonal growth cycle. Herbicidal, mechanical, and cultural methods used by land managers are costly, provide only temporary relief, and can cause damage to non-target plants in the area. In contrast to chemical controls, biological control agents offer a self-sustaining, environmentally friendly, and cost-efficient method for managing this weed. A biological control program against air potato was started in 2002 after the accidental discovery of a leaf feeding beetle (Lilioceris cheni) (Coleoptera: Chrysomelidae) from air potato’s native range in Nepal. Later, the same beetle was discovered in China. Extensive testing at the USDA-ARS Invasive Plant Research Laboratory in Fort Lauderdale, FL, showed that both the Nepalese and Chinese beetles are highly specific, so federal and state regulatory agencies approved their release in the United States. Adults and larvae feed on air potato leaves, ultimately causing vines to die early and significantly reducing bulbil production. The beetles are relatively less effective at controlling air potato vines in urban and suburban areas, where mosquito spraying programs interfere with the beetle’s life cycle, but they are very effective in rural areas, federal, state and local parks, and other natural areas with none or limited sprays.

Technical Abstract: The air potato vine (or air yam), Dioscorea bulbifera, a member of the Old World yam family, was introduced to the United States over two centuries ago and has become one of the most serious exotic invasive weeds in Florida. It vigorously invades both disturbed and undisturbed habitats under public and private ownership across Florida, southern Georgia, Alabama, Mississippi, Louisiana, and Texas. Research shows the vine grows up to 25 cm (10 inches) per day and branches profusely. These attributes enable air potato to climb up and over other vegetation, smothering trees, shrubs, and other plants. As it grows it produces numerous aerial tubers (“bulbils”), which fall to the ground when the vines die back in winter. The bulbils and underground tubers sprout in spring and repeat the seasonal growth cycle. Herbicidal, mechanical, and cultural methods used by land managers are costly, provide only temporary relief, and can cause damage to non-target plants in the area. In contrast to chemical controls, biological control agents offer a self-sustaining, environmentally friendly, and cost-efficient method for managing this weed. A biological control program against air potato was started in 2002 after the accidental discovery of a leaf feeding beetle (Lilioceris cheni) (Coleoptera: Chrysomelidae) from air potato’s native range in Nepal. Later, the same beetle was discovered in China. Extensive testing at the USDA-ARS Invasive Plant Research Laboratory in Fort Lauderdale, FL, showed that both the Nepalese and Chinese beetles are highly specific, so federal and state regulatory agencies approved their release in the United States. Adults and larvae feed on air potato leaves, ultimately causing vines to die early and significantly reducing bulbil production. The beetles are relatively less effective at controlling air potato vines in urban and suburban areas, where mosquito spraying programs interfere with the beetle’s life cycle, but they are very effective in rural areas, federal, state and local parks, and other natural areas with none or limited sprays.