Southeast Asia
Air potato (Dioscorea bulbifera)
Eggs are cylindrical, up to 1 mm long, and pale yellow at first, darkening to a greenish-gray as the larvae inside develop. Early larval instars are translucent white while later instars are grayish-red. Late instars are up to 7 mm long and have a black head capsule. Pupae are peach-colored and are often enclosed in a foam-like matrix covered with soil and other particles. Adults are up to 10 mm long with bulging eyes and black heads, legs, abdomens, and antennae. The elytra are brownish-orange to bright red.
Adults feed on air potato bulbils and lay eggs (900+ during their lifetime) on the surface of or within fallen bulbils. Very rarely, females may oviposit on air potato leaves. Through four instars, larvae feed primarily within air potato bulbils, though some early instars may feed on the undersides of young air potato leaves. Newly hatched larvae are unable to penetrate bulbils on their own and must rely on adult feeding holes; however, later instars can pierce bulbil skin. Several larvae can be found feeding in a single bulbil. 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. Two to eight individuals are often found in the same foam matrix which may be found attached to a bulbil or be free in the soil. Emerging adults feed on fallen air potato bulbils over the short Florida winters. Adults live four months on average, and there are multiple overlapping generations per year.
Adult and larval feeding prevent bulbils from sprouting, reducing air potato’s ability to reproduce and spread.
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