Air potato leaf beetle (Lilioceris cheni)
The air potato leaf beetle (Lilioceris cheni) is a natural enemy of air potato (Dioscorea bulbifera). This species was first found in Asia, and after extensive testing, this beetle was approved for release in United States. Beetle populations present in Louisiana are originally from Nepal.
Air potato leaf beetles are about 1/3 inch long by 1/6 inch wide. Adults (left) are shiny, with an orange abdomen and black underside. Larvae (right) are grublike and may be covered in a sticky secretion. They are often found feeding on air potato leaves.
Adult beetles lay pale yellow, cylindrical eggs on newly developing leaves. Eggs hatch in four days and larvae begin feeding voraciously on leaf tissue. Larvae go through four instars and then drop to the ground to pupate, where they make a cocoon out of soil and other materials. Adults emerge and continue feeding on the vines, or may disperse to find a mate. Multiple generations can occur in a season. In winter, adults burrow into leaf litter and enter a state of diapause.
It is easy to determine if air potato leaf beetles are present by looking for characteristic skeletonization of leaves. Small brown or black frass (droppings) on the leaves are also a clue that the beetles are feeding. Beetles will also feed on tubers and aerial bulbils, but prefer tender leaves.
Feeding by air potato leaf beetles can reduce the size of an infestation over time by depleting the plant’s nutrient reserves and reducing new growth. Weakening of the plant often results in early senescing (yellowing and die-back of vines) and reduced vigor of regrowth. Initial observations in Louisiana suggest that reductions of air potato coverage can occur within a year of beetle releases.
For more information on the air potato leaf beetle, see the LSU AgCenter Bug Biz.
The LSU AgCenter and the LSU College of Agriculture