Asia
Air potato (Dioscorea bulbifera)
Two genotypes have been released: Chinese and Nepalese. Eggs are pale yellow, cylindrical, and up to 1 mm long. Early instar larvae of the Chinese genotype are reddish while those of the Nepalese genotype are more yellowish; both become gray in later instars. Late instars are up to 7 mm long and have a black head capsule. Larvae are frequently coated in a sticky secretion to which fecal matter adheres, and mature larvae often have a noticeable hump where the abdomen begins. Pupae are pale orange, up to 7 mm long, and enclosed in a foam-like matrix covered with soil and other particles. Adults are up to 9 mm long with bulging eyes and black heads, legs, abdomens, and antennae. The elytra of the Chinese genotype are typically red, while the Nepalese genotype elytra are a rusty orange.
Overwintering adults emerge in spring, feed on air potato foliage, and lay eggs (750–1900+ during their lifetime) in loose clusters on the undersides of expanding air potato leaves. Adults chew through the veins of a young leaf prior to ovipositing, causing leaf edges to cup or curl inwards. Through four instars, larvae feed on air potato leaves, skeletonizing leaves from the undersides; they also feed on vine growing tips and occasionally newly forming bulbils. At maturity, larvae enter the soil and orally secrete a foam-like substance in which to pupate. The foam-like substance becomes covered with soil and other particles and hardens. Many pupae are often found in the same foam matrix. Emerging adults feed on air potato foliage, and occasionally newly forming bulbils, before overwintering in soil and plant litter. Adults can live longer than one year, and there are multiple overlapping generations per year.
Adult and larval feeding reduce photosynthetic capacity, stunts vine growth and biomass, and reduces bulbil production.
Dray, F.A., Jr., and M.B. Rayamajhi. 2025. Air Potato Biocontrol Agents: History and Ecology in North America. In: R.L. Winston, Ed. Biological Control of Weeds in North America. North American Invasive Species Management Association, Milwaukee, WI. NAISMA-BCW-2025-15-AIR POTATO-A. https://bugwoodcloud.org/resource/files/33608.pdf