Air Potato Vines and Leaf Beetles

Air Potato Vines and Leaf Beetles

Several Extension offices in the Panhandle are collecting air potato bulbils for National Invasive Species Week. Photo credit: Esther Mudge, Escambia County

The non-native invasive air potato vine (Discorea bulbifera) has wound its way throughout Florida, from pine forests and creek floodplains to backyards. Their heart-shaped leaves are most noticeable in the spring and fall, where they can take over large areas, not unlike their fellow invasive vine, kudzu. In the fall, the plant produces a potato-like tuber called a bulbil, which grows above ground on the vine. The bulbils drop in the winter and then produce new vines the following spring.

The vine’s growth has been uncontrolled or kept back by herbicide for years, until researchers discovered a biological control insect known as the air potato leaf beetle (Liloceris cheni). In the vine’s native Nepal and China, the beetle controls growth by surviving on the leaves of the air potato, its sole food source. After extensive study, the USDA approved the use of these beetles in Florida to control the air potato vine population here. UF IFAS Extension offices statewide have participated in these beetle release programs, providing thousands of beetles to homeowners and property owners seeking to manage the invasive vine using a chemical-free technique. Left alone, air potato vines can smother full-sized trees, blocking the sunlight and causing them to collapse under the weight of the intertwined vines.

From 2012-2015, beetles were able to reduce air potato vine coverage and bulbil density by 25-70% (depending on location and density of beetle population). The active beetle-production phase of a UF IFAS grant has ended, but researchers are committed to the goal of reducing this nuisance species statewide.

To assist with this process, several Extension offices in the Panhandle are sponsoring a bulbil collection during National Invasive Species Week (NISAW, February 23-29).  This effort will serve two important roles: to remove bulbils from the natural environment and to provide a seed source for university researchers seeking to grow air potato vine in a controlled environment, sustaining a continued population of air potato beetles for distribution.

For more information on Air Potato Vines and Leaf Beetles, visit https://bcrcl.ifas.ufl.edu/airpotatobiologicalcontrol.shtml or contact your local County Extension office.

May 18, 2018, Air Potato Challenge: Beetles Available for the Public

Air potato leaf beetle attacking the invasive air potato plant.

Air potatoes got you down? Have no fear, for the Air Potato Challenge is coming to Leon County!

Register now to attend the Air Potato Challenge event on May 18, 9 a.m. to 12 p.m. at the FAMU Center for Viticulture and Small Fruit Research (6361 Mahan Drive, Tallahassee, FL) and receive a supply of air potato beetles to use on your property.

After years of testing, air potato beetles became available as a biological control in 2012 to help combat the invasive herbaceous perennial air potato vine (Dioscorea bulbifera). Air potatoes arrived in south Florida from China in the early 1900s and have steadily crept north until they are now invading the Panhandle Region. Fortunately, air potato beetles have dietary requirements that are very specific, relying strictly upon air potatoes to complete their life cycles.

This is why a team of researchers and Extension agents have come together to help spread air potato beetles as a biological control strategy. Many agencies and counties are involved in this effort, including UF/IFAS Extension St. Lucie County, UF/IFAS Indian River Research and Education Center, the Florida Department of Agriculture Division of Plant Industry, the USDA, Florida Fish and Wildlife, UF/IFAS Extension Leon County, and Florida A&M University.

From 9 a.m. to noon on May 18, Florida residents and public land managers are invited to come out to the FAMU Center for Viticulture and Small Fruit Research to get more information about the invasive air potato and its biological controller, the air potato beetle, and receive a supply of beetles to use on their properties. Please pre-register on the Eventbrite page  (https://www.eventbrite.com/e/may-18-2018-air-potato-challenge-leaf-beetles-available-for-the-public-leon-county-fl-tickets-44793035174).

You can find more information about air potatoes and air potato beetles on the UF/IFAS Solutions for Your Life Air Potato Biological Control page (http://bcrcl.ifas.ufl.edu/airpotatobiologicalcontrol.shtml).

What: Air Potato Challenge
Where: FAMU Center for Viticulture and Small Fruit Research, 6361 Mahan Drive, Tallahassee, FL
When:
May 18, 2018, 9 a.m. to 12:00 p.m.
Cost: Free of charge, but please pre-register
Registration: https://www.eventbrite.com/e/may-18-2018-air-potato-challenge-leaf-beetles-available-for-the-public-leon-county-fl-tickets-44793035174

Welcome the Air Potato Leaf Beetle

Welcome the Air Potato Leaf Beetle

Air potato leaf beetle. Photo credit: Les Harrison, UF/IFAS.

A small, but brightly colored beetle has appeared in north Florida: the air potato leaf beetle (Liliocetis cheni), a native of East Asia. The beetle, less than half an inch long, has a candy apple red body that stands out against green leaves and the more muted earth tones of most other bugs. The striking bright glossy red coating would be the envy of any sports car owner or fire truck driver.

Unlike other arrivals to the U.S., this insect was deliberately released in 2012 for biological control of air potato. After years of testing, approval was finally given to release air potato leaf beetles to begin their foraging campaign against this invasive plant species. The beetle has very specific dietary requirements and only can complete its life cycle on air potato. The larvae and adults of this species consume the leaf tissue and occasionally feed on the tubers.

When a population of air potato leaf beetles finish off an air potato thicket, they go in search of nourishment from the next patch of air potato. They are sometimes seen during stopovers while in search of their next meal.

Air potato (Dioscorea bulbifera) is an herbaceous perennial vine which is easily capable of exceeding 60 feet in length. It quickly will climb over any plant, tree or structure unfortunate enough to be in its vicinity. The vine also produces copious quantities of potato-like tubers suspended from its vines. Unless collected and destroyed, most of the easily camouflaged potatoes will germinate and intensify the infestation.

Air potato. UF/IFAS Photo: Thomas Wright.

Air potato. UF/IFAS Photo: Thomas Wright.

Air potato came to Florida in 1905 from China and quickly escaped into the wild. By the 1980’s it was a serious pest species in south and central Florida, but has gradually become established in the panhandle, too. Chemical control of the air potato has been difficult. Repeated herbicide treatments are required to kill a thicket with multiple plants.

Unlike the air potato leaf beetle that only eats air potato, kudzu bugs eat their namesake vine (kudzu), but also feed on a number of other plants including a wide selection of valuable legumes and be quite destructive. Kudzu bugs were accidently introduced in north Georgia in 2009 and have spread across the south in the ensuing years and become established in north Florida.

It is a pleasant surprise to know air potato leaf beetles are working to limit the invasive air potato vine, but it is sad to think there is plenty more for them to eat.

To learn more about the air potato and the beetle:

Natural Area Weeds: Air Potato (Dioscorea bulbifera)

Air Potato Leaf Beetle Publication

Beetles to the Rescue

Air-potato-with-bulbil-inset_largeAir potato (Dioscores bulbifera) is a perennial, herbaceous self-twining vine that can grow over 60 feet in length, enabling it to climb over and smother many native plants. The Florida Exotic Plant Pest Council (FLEPPC) lists air potato as a Category 1 invasive plant, which means that it has disrupted natural communities and ecological functions by displacing native plant species.

In 2012, a leaf feeding beetle (Lilioceris cheni) was introduced into South Florida from China for biological control of air potato. Although it is too early to determine any potential long-term impacts, the initial results have been promising. The larvae and adults of the air potato leaf beetle feed on the leaf tissue and occasionally the bulbils. The damage to the growing tips of the plant have dramatically reduced its ability to cover native vegetation. Extensive damage to air potato was evident within three months after the first release. Additionally, testing by scientists at the USDA/ARS Invasive Plant Research Laboratory in Fort Lauderdale concluded that the beetle will not complete development on any other plant found in Florida.air_potato_leaf_beetle09

airpotatobeetleThe female air potato leaf beetle lays an average of 1,200 eggs, which develop into larvae in about four days. The young beetles skeletonize the air potato leaves for the next eight days and then pupate into foam-like cocoons. Clumps of cocoons fall to the ground and the adult beetles emerge 13 to 16 days later. There can be a new generation of air potato leaf beetle every month while the weather is warm. For the winter, the adults hide in leaf litter and wait for spring.

 

The question now is: “How well will they survive through a longer, colder Northwest Florida winter?”. USDA scientists, UF Extension agents and citizen scientists in Bay and Okaloosa County hope to find out. Earlier this month, June 2015, air potato leaf beetles from the Hayslip Biological Control and Research and Containment Laboratory in Ft. Pierce were released into areas containing air potato. They will be monitored over the next year. Look for an update next summer.