I'm sure many of you could easily recognize air potato with its winding vines and heart-shaped leaves climbing high along roadsides, fence rows and natural vegetation, but could you recognize its key predator, the air potato leaf beetle? Believe it or not, a small, red leaf-feeding beetle is here to give the invasive air potato vine a run for its money!
The Issue with Air Potato Vine
Air potato (Dioscorea bulbifera) is a plant species that is native to Asia and was first introduced to the United States as a landscape plant but has now become one of Florida's most problematic invasive plants. Air potato has spread to 60 of the 67 counties in Florida, including Jefferson County. Air potato vines can grow up to 8 inches per day! The dense vines smother vegetation and displace native plants, trees and animals. The air potato vine is on the Florida Noxious Weed List. This means that is illegal to plant, propagate or move the air potato unless you have a permit.
The air potato vine spreads by vegetative reproduction. This is through the formation of aerial tubers, or bulbils that are formed in the leaf axils. The aerial tubers are roundish and vary in size. In addition to aerial tubers, air potato also produces underground tubers, making control that much more difficult. During the winter, the aerial tubers will drop to the ground and give rise to new vines in the spring.
Park managers and homeowners throughout Florida have battled with the air potato as its covered our landscape. For years, the primary means of control were by manually pulling, digging and destroying the tubers or by herbicide applications, until recently.
Classical Biological Control of the Air Potato Vine
Another method for controlling invasive plants is with classical biological control. This method involves searching for insects that feed exclusively on a plant in its native range and releasing them in an area that has been invaded by the plant. Scientists with the United States Department of Agriculture discovered the air potato leaf beetle (Lilioceris cheni) that feeds on air potato in its native range of Asia.
After extensive testing, scientist found that the beetle is species-specific and poses no risk to other plant species.
In 2012, air potato leaf beetles were released in Florida to help battle the air potato. Adults are bright red with a black head and legs and about the size of your pinky fingernail. The females lay white, pale eggs on the underside of leaves. The egg-laying process causes the leaves to curl and cup. In addition to that, larvae feed on the leaves and skeletonize the plant leaves. Feeding by the beetle negatively affects the growth and reproduction of the plant.
Air Potato Leaf Beetles in Jefferson County
Last week, I found several air potato leaf beetles feeding on the air potato vine we have at the Extension Office. I returned a week later and found the same vine was completely demolished by the air potato leaf beetles! It's likely the beetles have traveled from Tallahassee after a recent release back in May. Scientists are still evaluating the long-term impact on the beetle, but the initial results look promising for helping us combat the invasive air potato. Think you've seen an air potato leaf beetle? Give the Extension Office a call at (850) 342-0187 or snap a photo and send it in for identification to dsprague@ufl.edu.
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