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Has the Air Potato met its Match?


This climbing vine can literally shade out other plants.

The air potato vine (Dioscorea bulbifera) is native to Asia and Africa and has been in Florida since around 1905 when it was imported to assess its value for horticultural purposes. Now, millions of dollars are spent each year on trying to control its spread and return impacted habitats to their natural state. Many people do not realize yet that the plant is a bad actor and still add it to their home landscape for its attractive foliage. However, the Florida Dept. of Agriculture and Consumer Services knows the problem all too well and added the plant to their Noxious Weed List in 1999. This made it illegal to introduce, possess or move this plant without a permit, due to its highly invasive nature.

Air potato vines are successful in Florida for several reasons. First, the native climate range of the plant matches our own. Even in North Florida, where freezing temperatures kill the above-ground foliage, the potato-like tubers (bulbils) that give the plant its name are able to survive in the duff layer on the ground. Also, when a new plant arrives in the neighborhood, quite often there are no native critters that have adapted to use it as a food source and it grows unchecked. Many plants are not invasive in their native range because of the natural balance with predators but once transported elsewhere they can dominate an ecosystem. This is the case with air potato in Florida.
So what did scientists do when they started looking for a solution to the problem? They naturally searched the invader’s native range in China for what might keep it in check back home. Not coincidentally, they discovered a beetle species (Lilioceris cheni) that enjoyed a longstanding culinary relationship with the vine. These small (1/4 inch) red and black beetles have the ability to completely “skeletonize” the leaves, leaving only the tougher veins uneaten.

Late instar larva of beetle

Late instar larva of beetle

They are able to eliminate much of the above ground foliage and reduce the plant’s spread. Researchers began feeding trials with the beetles to determine if they would eat anything else. After extensive trials showed they had no desire to eat our native plant species a breeding program was undertaken to raise enough beetles for trials in the U.S. at research facilities. After this, small scale releases were attempted in the wild to determine if the beetles could accomplish their intended mission. The first releases took place in Florida in 2012 and early results seem promising.
The nearest recorded release of beetles to Franklin County took place in Panacea during 2014 but by August 2015 beetles were discovered by staff at the FDACS Shellfish Lab in Apalachicola happily feeding on air potato vines in the area. Adult beetles can fly and seem to be expanding their range to occupy that of their host plant. Since then, Extension staff have also seen the beetles in another nearby patch of air potato. Let’s keep our fingers crossed that they are able to stem the tide of a plant that definitely does not need to be living in our wild areas.
If you have an infestation of air potato there are a few things you can do. After the potatoes drop in the fall you can collect them and put them in the freezer to kill them and prevent them from starting new plants.

Collecting bulbils and freezing them helps with control.

Collecting bulbils and freezing them helps with control.

You can also request Liliocerus beetles for release by contacting the FDACS program that is raising them for this purpose.

Permanent link to this article: http://franklin.ifas.ufl.edu/blog/2015/10/26/has-the-air-potato-met-its-match/