Air 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 beetle up close. Photo by Julie McConnell
The 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 this coming summer.
Immature TSA fruit are resemble tiny watermelons. Mature fruit turn yellow and contain 40-50 seeds each. Photo credit: UF Hayslip Biological Control Research and Containment Laboratory
Florida ranchers know Tropical Soda Apple (TSA) as the “Plant from Hell”. It was first noticed in south Florida, but its seeds survive in the digestive tract of animals and it spread north through the movement of hay and cattle. TSA plants are covered with thorns and can make large sections of pasture nearly useless for livestock. Concerted efforts to lessen the population of TSA since its arrival have reduced the populations in pastures but it persists in sheltered or waste locations. Cattle, birds, deer and feral hogs ingest the mature fruits and spread the plants to loafing and browsing areas that may be inaccessible to mechanical treatment with anything larger than a hoe. According to Dr. Jeff Mullahey, who has been working on TSA since its appearance in south Florida, one plant can produce 40,000-50,000 seeds with seed germination ranging from 75%-100%. The seeds remain viable for at least three years. Be on the lookout for these while engaged in outdoor activities.
Isolated plants can be controlled by mechanical means. You won’t want to pull them up barehanded, though. Additional information and control methods are available at http://edis.ifas.ufl.edu/uw097, or contact your local Extension agent.
The rounded seedling leaf in the foreground has few spines, but all the later leaves do have them. Photo by Jed Dillard
Japanese Climbing Fern can quickly cover natural vegetation. Spores and small plants can be potentially transported in pine straw. Climbing ferns are a problem for managed timber and home landscapes. Photo by L. Scott Jackson
Both ferns reproduce and spread readily by wind-blown spores. Animals, equipment, and even people that move through an area with climbing ferns are very likely to pick up spores and move them to other locations on the property or even to other properties.
Japanese climbing fern is a delicate looking perennial climbing vine. It is capable of forming a dense mat-like thatch capable of covering trees and shrubs. Initially, it was introduced from Japan as an ornamental. It is scattered throughout the lower portions of Alabama, Georgia, Louisiana, South Carolina, and south into central Florida. Further planting or cultivation of this vine is prohibited by the Florida Department of Agriculture and Consumer Services.
Old World climbing fern has been a problem for many years in central and south Florida but it is currently moving north. The northern edge of its advance is now just south of Marion County.
Adequate control of both climbing ferns has been achieved with multiple applications of glyphosate. Other herbicides have also been used to control Japanese climbing fern.
As with most invasive plants, repeated and correctly timed treatments are likely to be necessary.
For more information about climbing ferns contact your local UF/IFAS Extension Office and read the following publication: http://edis.ifas.ufl.edu/fr133
Fences make good neighbors except when your neighbor is a Chinese tallow or popcorn tree. Seed is easily spread across property borders. Birds, storm-water, and vehicles are just few ways seeds move away from large trees. Photo by Scott Jackson.
Benjamin Franklin has been blamed for introducing the invasive Chinese Tallow tree to the Southeast when he mailed seeds to a planter after one of his trips to London in the late 1700’s. However, recent DNA work has traced the invasive strain to federal scientists’ importations in 1905.
No matter. The “Popcorn Tree,” as it’s also called because of its white seeds, has invaded the Gulf coast from Texas to Florida, especially the wetlands and bottomland forests. A mature tree may produce as many as 100,000 seeds annually. These seeds can be spread by birds or moving water and expedite the trees’ takeover of habitat. The sap and berries are toxic to humans and livestock. It has been planted for its red fall color, but it crowds out native wetland species such as black gum and red maple, both noted for their red fall leaves. Its tolerance to flooding and saltwater can also make it a threat to bald cypress.
Recently research by scientists of the US Forest Service and others has shown the dissolved oxygen and pH levels in the leaf litter of the tallow tree are fatal to the early stage eggs of the leopard frog. While tallow trees provide a nectar source for bees and have been investigated as a biofuel source, the damage to wetlands caused by these invaders more than offsets the positive aspects of the plant.
Small seedlings may be hand pulled, especially in wet areas, but care should be taken to leave no root pieces to resprout. Herbicides including triclopyr can control Chinese Tallow. More information is available at http://edis.ifas.ufl.edu/ag148 and http://plants.ifas.ufl.edu/node/676.
For local assistance, contact your county UF IFAS Extension office.
Coral ardisia is also known as coral berry, spice berry, and scratchthroat. It was introduced into Florida in the early 1900’s for ornamental purposes.
In the ensuing years it has since escaped cultivation and become established in hardwood hammocks and other moist woods of natural areas and grazing lands. Specimens have been collected from 19 western and south-central Florida counties as of 2004.
This evergreen sub-shrub reaches a height of 1.5 to six feet and tends to grow in multi-stemmed clumps. Leaves are alternate, 8 inches long, dark green above, waxy, without hairs, and have scalloped margins and calluses in the margin notches.
Flowers are typically pink to white in stalked axillary clusters, usually drooping below the foliage. The fruit is a bright red, globose, single-seeded berry, measuring approximately 0.25 inches in diameter. White-berried populations are also known to exist.
Coral ardisia is considered invasive. Control of coral ardisia may be accomplished by two methods. A low-volume foliar application of Garlon 4 or Remedy provides suppression of this plant. Complete foliar coverage is essential to success and retreatment will be necessary for complete control.
Basal bark applications with Garlon 4 or Remedy in an oil carrier can also be utilized for suppressing this invasive weed. Do not apply more than 8 quarts of Remedy or Garlon 4 per acre and treat no more than ten percent of the total grazed area if applying greater than two quarts per acre.
For more information contact your local UF/IFAS Extension Office and read the following publication: http://edis.ifas.ufl.edu/ag281
First let me explain that Seahorse Key is not in the Florida Panhandle but the story is interesting and a similar phenomena could occur here. Seahorse Key is an isolated island 3.6 miles southwest of Cedar Key in Florida’s Big Bend. There is a science lab owned and maintained by the University of Florida and Captain Kenny McCain on the island but can only reached by boat. Many forms of wildlife, particularly birds, seek out these isolate islands for nesting due to the lack of predators; and Seahorse Key is no exception. Another interesting point about this island is that it may have the highest density of cottonmouths in the state. Dr. Coleman Sheehy has been studying this population and estimates that there may be about 600 cottonmouths on the island. So what is the mystery?
Seahorse Key. An isolated island near Cedar Key Photo: FMSEA
Well we will first look back to last year and the nesting habits of the island’s birds. In 2014 Vic Doig of the U.S. Fish and Wildlife Service had logged seven different species of egrets, herons, cormorants, pelicans, and ibis nesting on the island. The number of nest per species varied from 100 to 5,000 with the white ibis producing the highest number. Dr. Sheehy surveys the cottonmouths by walking the shoreline and counting the number of snakes he encounters; which is typically around 30. The snakes and nesting birds are concentrated near Gardiners Point. Though the cottonmouths feed on rats they seem to rely on the fish that fall from the nests above.
As 2015 began the biologists noticed something different right off the bat. Though the birds were returning they were not returning in typical numbers, particularly the white ibis. These birds normally are the most abundant nesters on the island, but not this year. Dr. Peter Frederick, University of Florida’s Department of Wildlife Ecology and Conservation, did not seemed to alarmed by this knowing that white ibis are nomadic and do not stick with the same nesting locations for more than a few years. They tend to go where the food is most abundant. No mystery here… Then it happened…
A cottonmouth consuming a fish from a birds nest. Photo: University of Florida
Within a very short period of time, during the second week of April, all of the other birds began to leave. Researchers found the nests falling apart, no eggs or chicks within them, and hundreds of eggs on the ground. They also found the remains of 26 dead birds in the area. Where had they gone? What had happen?
Autopsied birds found no consistent cause of death. Most of the eggs on the ground had small holes indicating they were preyed upon by birds, most probably fish crows. However these birds are more opportunistic scavengers and would have fed on the eggs only after they had fallen from the nests. Researchers then discovered that many of the birds had relocated to nearby Snake Key. Though they had begun nesting there, fewer than half had done so. All seven species were found there but the number of nests had dropped from 100 – 5,000 to 50 – 600. Many of the birds were still missing. Where did they go? Better yet, why was Snake Key selected and Seahorse abandoned? And did the exodus of birds from Seahorse impact the snakes? The answer is… Yes. Dr. Sheehy’s survey found that the number of snakes encountered along the forest edge had dropped from 30 to 10. He noticed these snakes were thinner and he observed one cottonmouth consuming another, something he had not noticed before. The snakes had been impacted by the decline in nesting birds. What had happened on Seahorse Key?
One idea was put forth by Dr. Sheehy. He had noticed an increase in the number of raccoons on the island. Again, these isolated islands are selected for by nesting birds because of the lack of such predators and Dr. Harvey Lillywhite indicated that the typical number of raccoons on the island is zero. But Dr. Sheehy and Captain McCain had trapped and relocated seven raccoons earlier this summer. This suggests that a large group (large for this island) had found their way to Seahorse Key. Dr. Sheehy suggests that the cause of the movement of birds were the raccoons. There is no evidence of them attacking the birds but they believe the shear presence of the animals was enough for the birds to relocate. However Dr. Fredrick points out that (a) there was little evidence of the raccoons preying on the fallen eggs and (b) he could not find track or scat evidence of more than one or two raccoons on the island during his initial survey after the birds left. He is not so sure the raccoons were the cause.
Nesting birds on Seahorse Key Photo: courtesy of flickr
Then there is the question… Where did the seven raccoons trapped come from? One suggestion was that they were released by locals. This was based on the fact that raccoons captured were well fed and had a mild temperament, not what you typically encounter with trapped raccoons from the wild. Later there was a confirmed report of a local who does take in orphaned raccoons, raises them, and releases them; they could have released some on Seahorse Key – but this has not been confirmed.
So right now this mystery remains unsolved. But the story does indicate the types of problems that can occur when humans relocate animals to habitats they do not typically live in. It takes years for Mother Nature to develop a balance only to have it quickly fall apart by the human release of animals we wish to move or that we think will do better in another location.
