The air potato is a vine that grows by intertwining with trees. It can grow many feet from the base of a tree. The plant has broad heart-shaped leaves that are smooth. It belongs to the yam family. The aerial yam is native to Africa, Asia, and North Australia. Other names used for the plant include potato yam, cheeky yam, bitter yam, and air yam. It is a perennial plant that has a lifespan of more than 2 years. This plant is a known invasive, and in this article we will talk about how to remove air potato from your yard.
During fall, the air potato dies and flourishes during spring from underground tubers. The plant produces bulbils that sprout to new plants. The plant forms a dense canopy that smothers other plants after growing.
The bulbils are known as “potatoes” with smooth skin, or brown and rough-skinned. The scientific name of the weed is Dioscorea bulbifera. The plant produces tiny white flowers that grow in clusters. It was first seen in the USA in the 1770s. The plant is classified as noxious. This means that its cultivation, propagation, possession or movement is against the law.
How to Identify Air Potato
Air potato belongs to the yam family. It has broad cordate (heart-shaped) leaves which are arranged alternately on the stem. The primary veins of the leaves originate from the base. Its uncommon flowers arise from the axils and grow in panicles of around 4 inches. The primary method of production is through bulbils which fall and produce new vines.
Winged yam is quite similar to air potato. The difference is its winged internode where it derives its name. Unlike the aerial potato, winged yam has opposite leaves which give it a distinctive characteristic. The plant can grow up to 30 feet which is short of 70-100 average height of air potato.
The air potato whirls around other plants in an anti-clockwise direction, unlike winged yam that whirls clockwise. Though winged yam is invasive, it is not as problematic as the air potato. It is important to note the plant is toxic and thus should not be consumed. This is another reason to remove air potato from your yard.
Natural Habitat of the Aerial Yam
The plant is common in forests. It can be found in mesic, moist and hardwood forests. It does not grow near the coast because it is intolerant to salty water. Air potato can grow on most soils but does well in loamy to clay soils. The plant grows at an average of 8 inches in a day thus outdoing natural vegetation. This makes it difficult to remove air potato completely.
Food Value of Air Potato
It is essential to note that some species of the plant are poisonous before trying out recipes or medication. Most of the species in areas like Florida are toxic and should not be consumed. In Asia, there are cultivated varieties that are prepared like ordinary yams. However, they should be boiled to remove their bitter taste and slippery texture.
Potato yams also contain useful flavonoids that have anti-inflammatory benefits. Tubers of the plant are said to contain poisonous glucoside. There are preliminary studies on the use of the plant tuber for cancer treatment, anti-oxidation properties, and tumor inhibition. Over-consumption of edible air potato can cause poisoning. Therefore, it should be consumed with moderation.
The plants have a compound called diosgenin which is used in the manufacture of steroids.
Why Air Potato is Invasive and How it Spreads
The aerial yam is considered invasive and noxious. This means that it inhibits the growth of other plants thus reducing vegetation cover and reduces animal habitat. Air potato does not reproduce sexually because, in some regions, only one sex is found. For example, in Florida, only the female aerial potatoes have been found. The plants reproduce asexually through the bulbils and tubers. They also form an extensive and dense network of the root system which is difficult to uproot.
Here are some reasons why air potato is a threat to the ecosystem:
The plant is fast-growing
Air potato can grow for up to 8 inches a day. This means in a week it can grow almost 5 feet taller. Most plants cannot keep up with the vast growth. Therefore, the plant covers other plants and inhibits their growth.
Air potato can grow to the peak of the tallest trees. Its vegetative nature and broad leaves form a canopy and block other plants as well as animals from access to sunlight and at times water. The situation leads to alteration of the ecosystem as plants and animals die due to the deprivation.
Air potato reproduces by means of bulbils and tubers. The bulbils can sprout at a very early stage, thus making it difficult to remove air potato from your yard. During fall, the plant dies but comes to life in summer by means of bulbils and tubers. The vines produce numerous bulbils which then sprout to new vines. The tubers can survive for a long time in case the stem is cut off. The bulbils sprout and form a dense network of stems which can prove difficult to eradicate.
Unlike other plants in the ecosystem that have several predators in animals and plants, air potato has few if any predators. The only reported natural enemy to the plant is a beetle native to Asia. In such a case, breeding the beetles and introducing them into a new ecosystem without altering the natural environment becomes difficult.
The plant has posed a big problem in some regions like Florida where it has invaded parks, pinelands, and natural area hammocks. It has natural vegetation off sunlight and nutrients.
How to Remove Air Potato
Once established, it is difficult to remove air potatoes because of its fast growth. Therefore, it is advisable to uproot any plants near your homestead to prevent spread into other areas. In case the plants are established and have produced bulbils, you can remove air potato during winter when the plants are less dense.
The plants are dispersed by water, human activities or animals. During mowing, you should not dispose of the bulbils in areas where they can germinate. It is also advisable to clean farming equipment when working in an area infested by the weeds. After floods, extra care should be taken to eliminate any bulbils because the spread might be extensive. In case air potatoes are already growing in your farm or homestead, here are some eradication measures that you can use.
Physical removal of air potato is only effective where the weeds have not spread. You can uproot the vines and remove any bulbils for disposal. Air potatoes climb to the top of trees making it hard to control mechanically without affecting natural vegetation. Trying to climb on trees to remove the vines can destroy the trees allowing more space for the air potato to grow. Burning the plants also causes vast destruction of natural destruction. Mowing can also make the problem worse because it can lead to the spread of the bulbils to other areas.
In some areas like Florida, the State Government calls upon volunteers to help in eradication of bulbils in a project dabbed air potato round-up. The people as well as organizations come together and help in the collection of the bulbils from public parks. This method can work in areas that are not heavily infested. It also helps in the prevention of reinfestation. However, for it to be effective, it should be repeated regularly to keep the bulbils as well as tubers at bay.
The locals should also be informed about the impact of the vines and attempts to control so that air potatoes do not spread from private to public land. Underground tubers should also be removed to prevent sprouting.
Although it is one of the best air potato control methods, it is quite expensive because it requires several applications to be effective. Foliar application of Garlon 3A or Garlon 4 can help in the weed control. You should read the manufacturer’s instructions for you to realize positive results. You should also apply the solution selective to avoid damage to the untargeted vegetation. The use of glyphosate like RoundUp can also help in the control of air potato.
In case the plants are growing to the top of trees, you can pull them to the ground without uprooting. This prevents damage to natural vegetation. You should apply the herbicides when the roots are intact so that the chemicals can move down to the root. However, it might not be practical to pull down the vines for heavily infested areas.
It is advisable to apply the herbicides during spring and summer when the air potatoes are actively growing. You should also apply the method when the weather is moderate (no strong winds or rain) to ensure that the chemicals are effective. Application on a sunny day also prevents erosion of the chemicals to water bodies. You should also put on the necessary protective clothing to avoid inhalation or contact with the chemicals.
If you are not trained in herbicide application, you can contact a local extension officer for training. You can also hire a vegetation management contractor to help you in the control of the aerial yams.
Some predator beetles from China and Nepal are used in air potato control. The beetles feed on air potato vines only. Therefore, you don’t have to worry about the other vegetation. The insects also reproduce fast making their establishment easy. They can live for up to 6 months. Within this period, the beetles can lay up to 4,000 eggs.
Chinese beetles are bright red and were discovered in Yunnan Province. Nepalese beetles are brown in color and were discovered by researchers from the Invasive Plant Research Laboratory in Fort Lauderdale. Adult females feed on the leaves of air potato and also lay their eggs on the leaves. The eggs take 4 days to hatch and form larvae that feed on the leaves for around a week. Larvae can also feed on bulbils and tips of the vines, preventing upward growth of the plants.
The beetles have shown positive control of the vines as well as bulbils in Florida. The State Government provides free beetles to locals (25-50) to help in the control of the invasive plant. The beetles reproduce and within no time they overpower the air potatoes by destroying the leaves. Once the leaves are destroyed, they cannot make food for the plant leading to death.
Although this air potato biological control method is slow, it is sustainable because the beetles increase and reduce the plant cover. The number of beetles is also controlled by the aerial yam population because they cannot feed on other plants. Over time, the number of beetles reduces as the plants decrease. Consequently, a balance in the ecosystem is achieved and other plants, as well as animals, can also thrive.
Bonus: Air Potato Facts
- Air potato is among the fastest-growing plants at an average rate of 8 inches a day. The plant robs its host sunlight and they eventually die because they cannot undertake photosynthesis.
- Some cultivars are edible, especially in Asia. However, because they are very bitter, they are boiled before consumption to reduce the bitterness. Most species in the USA are tasteless, toxic and at times even poisonous.
- Air potatoes produce a chemical called diosgenin which is used in making steroids.
Aerial yams can destroy your landscape if left without control. They smother natural vegetation and can also cover large trees. Apart from that, the vines destroy the natural habitat for some living organisms like insects. The plant blocks natural vegetation as well as these organisms from accessing sunlight. Biological control of the plant is the most effective and environmental friendly because it does not affect natural vegetation. The method also prevents further spread of the vines to other areas. Control also requires the collective effort of the community because the plants can easily spread.
- University of Florida: Dioscorea bulbifera https://plants.ifas.ufl.edu/plant-directory/dioscorea-bulbifera/
- Air potato biological control- http://bcrcl.ifas.ufl.edu/airpotatofiles/airpotatoFAQ.shtml
- National Invasive Species Information Center USDA: Air potato- https://www.invasivespeciesinfo.gov/profile/air-potato
- Everglades Cooperative Invasive Species Management Area: Air potato – https://www.evergladescisma.org/the-dirty-dozen/air-potato/
- Texas Invasive Species Institute: Dioscorea bulbifera– http://www.tsusinvasives.org/home/database/dioscorea-bulbifera