by Carrie Stevenson | Mar 2, 2017
Guest Blogger – Dr. Steve A. Johnson, Associate Professor & Extension Specialist, Department of Wildlife Ecology and Conservation, University of Florida
Cuban Treefrog. Photo credit: Steve Johnson
The National Invasive Species Council defines an invasive species as one that is introduced outside its native range where it causes harm (or is likely to) to the environment, economy, or human quality of life. The Cuban Treefrog in Florida qualifies as invasive under all three parts of this definition. Introduced from Cuba to Key West inadvertently in a shipment of cargo about 100 years ago, this frog is now established throughout Florida’s peninsula, and isolated records from numerous panhandle counties continue to accumulate. There are many records of Cuban Treefrogs from other states in the US, and even Canada. Most of these frogs originated in Florida and found their way to points beyond as hitchhikers on vehicles or as stowaways in shipments of ornamental plants. Fortunately, Cuban Treefrogs do not appear to have gained a permanent foothold—yet—outside of the Sunshine State.
Cuban Treefrog eating a Green Treefrog. Photo Credit: Nancy Bennett
Cuban Treefrogs are well documented predators of Florida’s native treefrogs and are likely responsible for declines in native treefrog numbers, especially in suburban neighborhoods. Fortunately, research has shown that when native frogs (e.g., Squirrel and Green Treefrogs) are still present that they respond favorably to the removal of their invasive cousins. Cuban Treefrogs are known to seek shelter in electrical utility equipment or even a home air-conditioning units, and as they climb around they may cause short circuits, leading to costly repairs. They also invade homes, ending up in a toilet at times, and have also sent young children to the emergency room. The frogs exude a noxious skin secretion when handled, which is extremely irritating to mucous membranes, especially one’s eyes. So be sure to wash your hands thoroughly after handling a Cuban Treefrog.
To mitigate the negative impacts Cuban Treefrogs are having on Florida’s native wildlife, as well as their effects on our quality of life, I recommend that these invaders be captured and humanely euthanized. For tips on how to capture, identify, and humanely euthanize these frogs visit http://ufwildlife.ifas.ufl.edu/ and also read “The Cuban Treefrog in Florida”. Report sightings of this species outside of the Florida peninsula to Dr. Steve A. Johnson, and within the peninsula report them on EDDmapS.
by Rick O'Connor | Mar 2, 2017
Beach Vitex Blossom. Photo credit: Rick O’Connor
Research shows that the most effective time to deal with an invasive species, both in terms of controlling or eradicating the species and money spent to do so, is early on…. What we call Early Detection Rapid Response. Beach vitex is a good candidate for this.
The first record for vitex in the Florida panhandle was in 2012. A local citizen in Gulf Breeze (Santa Rosa County) reported it on her beach and believed it may have come from Santa Rosa Island… it did. The barrier island location was logged on EDDmaps and the Gulf Breeze plants were removed. A quick survey of Florida on EDDmaps found that the only other location was in Duval County – 3 records there. So this was not a wide spread plant in our state and could be a rare case for eradication. That was until I surveyed Pensacola Beach on a bicycle and found 22 properties with it. Soon afterwards, it was found on the shores of Perdido Bay and concern set it that it might be more widespread than we thought.
Vitex beginning to take over bike path on Pensacola Beach. Photo credit: Rick O’Connor
We tried to educate the property owners about the issue based on what we learned in South Carolina, where there is a state task force to battle the plant, and suggested methods of removal. Many property owners began the process, which can take several treatments over several years, and, with the help of University of West Florida students, removed all of the vitex from public land on Santa Rosa Island. We were feeling good that we might still be able to eradicate this plant from our county… and then I went for a hike in the Gulf Islands National Seashore… yep… found more… almost 10,000 m2 of the plant. UWF and Sea Grant have worked hard over the past year to remove these plants, and have removed all but one section. Recently I received an email letting me know that it was found in Franklin County. They have since logged this on EDDmaps and have begun the removal process. However, this begs the question… where else might this plant be in the panhandle?
Beach vitex (Vitex rotundifolia) is a salt tolerant plant that does well in dry sandy soils and full sun; it loves the beach. We have found it in dune areas above the high tide line. It was brought to the United States in the 1950’s for herbarium use. By the 1980,’s the plant was used in landscaping and sold at nurseries. It was first used in dune restoration in South Carolina after Hurricane Hugo, and that was when the trouble began.
Vitex growing at Gulf Islands National Seashore that has been removed. Photo credit: Rick O’Connor
The plant grows very aggressively during the warmer months. It out competes native dune plants and quickly takes over. Growing 2-3 foot tall, this woody shrub has above ground rhizomes that can extend over 20 feet. Secondary roots begin to grow from the nodes along these rhizomes and it quickly forms an entangled mat of vines that blocks sun for some of the native plants. There has also been concern for nesting sea turtles. The rhizomes can over take a nest while incubation is occurring and entrapping the hatchlings. The plant has become such a problem in both North and South Carolina that a state task force has been developed to battle it. Vitex can spread either vegetative or by seed, both can tolerate being in salt water and can be dispersed via tides and currents. The plant has 1-2” ovate leaves and violet colored blossom, which can be seen in late spring and summer. The leaves become a rusty gray color during winter. The seeds, which are found in late summer and fall, are spherical and gray-purple in color. Vitex produces many seeds, an estimated 22,000/m2, and – in addition to being carried by the tide – can be transported by birds as well.
Again, we are hoping that the plant has been discovered early enough to control, if not eradicate, it… HOWEVER, WE NEED YOUR HELP. If you think you may have seen this plant along your coasts, please contact your county Sea Grant Extension Agent for advice on how to manage it.
by Sheila Dunning | Mar 1, 2017
Swamp Redbay Tree infected with Laurel Wilt. Photo credit: Sheila Dunning
Many invasive plants and insects are introduced in packing materials, including 12 species of ambrosia beetles, which embed themselves in wood used as crates and pallets. While these tiny beetles don’t actually feed on wood, the adults and larvae feed on fungi that is inoculated into galleries within the sapwood by the females when they deposited their eggs. While the ambrosia fungus keeps the beetles alive, it kills the host tree. This is the projected fate of redbay trees (Persea borbonia) due to the Redbay Ambrosia Beetle.
First detected in the United States in a Georgia trap in 2002, Xyleborus glabratus, the Redbay Ambrosia Beetle, caused substantial mortality of redbay in northern Duval County, Florida in 2005. This ambrosia beetle introduces fungal spores, (Raffaelea lauricola) from specialized structures found at the base of their mandibles into the vascular system of plants when boring into host trees of the Lauraceae family. This insect and disease complex has collectively been named “Laurel Wilt.” Infected redbays, assafrass and avocado trees wilt and die within a few weeks or months.
Ambrosia Beetle life stages
The Redbay Ambrosia Beetle is a shiny black, cylindrical insect about 2 mm in length. The males are flightless and the females can only fly short distances (1 – 1.5 miles). Therefore, host trees are often attacked many times and stands of redbays are damaged quickly. Small strings of compacted sawdust may protrude from the bark at the point of initial attack. However, wind and rain easily remove this sign leaving the only symptom to be the total browning of foliage in a section of the tree’s crown. Since the fungus blocks the xylem (water-carrying) tissue of the redbay, it appears to wilt while leaves remain attached. Once infected, the trees cannot be saved.
To avoid spreading the beetle and pathogen to new areas, the trees need to be cut down and wood or chips from the infested trees should not be transported off site. Where allowed, the materials should be burned on site. Protection of unaffected trees is possible with expensive pesticides if applied in a timely manner and using the correct techniques. Removal of all susceptible tree species is not recommended. The survivors may hold a genetic tolerance.
by Carrie Stevenson | Mar 1, 2017
Special Guest Blogger – Lorraine Ketzler, Biological Science Technician with US Fish and Wildlife Service
There have been several fungal invaders entering and spreading within the US in recent years and I’d like to draw attention to four of them:
Eastern red bats being surveyed for White-nose Syndrome at Talladega National Forest, AL. Photo credit: Lorraine Ketzler
- White-nose Syndrome (WNS) in bats (Pseudogymnoascus destructans)
- Chytridiomycosis (Chytrids) in frogs (Batrachochytrium dendrobatidis)
- Chytridiomycosis (B-sal) in salamanders (Batrachochytrium salamandrivorans)
- Laurel wilt disease (Raffaelea lauricola) in Lauracea family trees (redbay, sassafras, avocado and others), transferred by the invasive redbay ambrosia beetle (Xyleborus glabratus).
These diseases have devastating effects on multiple species. Bats, frogs, and salamanders are important insect predators, and all species –including trees- cycle nutrients through ecosystems to provide carbon storage benefits as well as other services. Bat populations in North America are declining precipitously as WNS marches westward across the continent. Many frog populations across the globe have disappeared because of Chytrids, with several species recorded as extinct and some are being listed under the Endangered Species Act. In addition to nutrient cycling, Lauracea trees benefit humans as food crops, aromatic ornamental trees, and medicinal plants. However, Laurel wilt disease is found in nearly every county in Florida, and continues to spread throughout the southeast.
The state and the US must remain vigilant and monitor against the introduction of B-sal, a recently discovered and highly transmissible disease spread through pet trade salamanders. It has not yet been observed in the US, but has caused widespread declines in native salamanders of the Netherlands and UK.
Unprecedented numbers of new and emerging pathogenic fungi continue to be discovered. Fungi genomes are amazingly adaptable, overcoming plant and animal defenses, and becoming resistant to fungicides. Increasing human traffic, trade, and disturbance introduce these pathogens to new habitats. Trade ports are key introduction sites. Always practice decontamination procedures when handling wildlife and native plants, even in areas without confirmed infections to prevent the spread of disease to new populations.
Help Stop the Spread of Non-native Species
by Sheila Dunning | Feb 28, 2017
Cuban Anole. Photo credit: Dr. Steve A. Johnson, University of Florida
The brown anole, a lizard native to Cuba and the Bahamas, first appeared in the Florida Keys in 1887. Since then it has moved northward becoming established in nearly every county in Florida. By hitching a ride on boats and cars, as well as, hanging out in landscape plants being shipped throughout the state, the Cuban anole (Anole sagrei) has become one of the most abundant reptiles in Florida. However, the native Carolina green anole (Anole carolinensis) has been impacted.
While both anole species are capable of thriving on the ground or in the trees, the invasive brown anole has altered the behavior of the native green anole by forcing them to remain arboreal. Anoles eat a wide variety of insects, spiders and other invertebrates. Cuban brown anoles feed on juvenile green anoles and their eggs, reducing their population even more. Brown anoles are brown to grayish in color. While they can adjust to various shades of light or dark, brown anoles cannot turn green. The native Carolina anole can camouflage itself by altering its skin color from light green to dark brown, including many hues in-between, but have no distinctive markings on their backs. Male brown anoles often have bands of yellowish spots, whereas females and juveniles have a light vertebral stripe with dark, scalloped edges. An additional identification feature is the dewlap of the male Cuban anole. Male anoles extend the skin of their lower jaw (the dewlap), displaying a bright orange to red color, in order to attract females or warn other males. Cuban brown anoles have a white line down the middle of the dewlap.
Egg surface of Native anole (left) vs Cuban anole (right). Photo credit: Todd Campbell
If the Cuban brown anole and Carolina green anole are placed side by side, the one with the shorter snout is the brown anole. Throughout the warm months, female anoles lay single, round eggs in moist soil or rotten wood at roughly 14 day intervals. The eggs of brown anoles have longitudinal grooves, whereas green anoles have raised bumps. Once identified, control measures can be taken. Brown anole eggs can be destroyed by freezing or boiling. Adult brown anoles can be located and captured by performing night time hunts with lights. Being diurnal, cold blooded creatures, Cuban anoles tend to congregate together under shrubs and along structures. Once collected the invasive Cuban brown anoles can be humanly euthanized by rubbing lidocaine on their skin and placing them in the freezer.
by Rick O'Connor | Feb 28, 2017
Torpedo grass. Photo credit: Rick O’Connor.
They say the best time to attack an invasive species is early in its arrival. In the early stages is your best chance, using the most cost effective methods, of eradicating an invasive species from a region. Hence our focus on Early Detection Rapid Response (EDRR) list. That is not the case with Torpedo Grass. It is now found in all Gulf coast states and along the Atlantic border to North Carolina. In Florida, it has been reported from 64 of the 67 counties and has also been reported in California and Hawaii. However, it is a problem plant and property owners should try to manage it as best they can.
There is a discussion as to the origins of torpedo grass (Panicum repens). Some say Europe, others Australia, but we do know it is not native to the United States. It was first introduced here in the late 19th century as a forage grass for livestock. Being a tropical-subtropical plant, the introduction was in the southeastern U.S. The young shoots have been selected by forging mammals, livestock and otherwise, but older plants become tough and the livestock ignore them for other species. There are reports of waterfowl and songbirds using torpedo grass as habitat. However, the cons out weigh the pros on this one.
Torpedo grass grows very quickly using underground rhizomes. Though they do produce seeds, these rhizomes, and their fragments, are the primary method of propagation for this plant. It has been found that rhizomes buried as deep as 20 inches can sprout shoots. This aggressive plant spreads quickly, outcompeting native grasses in disturbed areas. They will displace forage grasses that livestock prefer and can inundate a pasture very quickly. Though it is drought tolerant, torpedo grass prefers moist soils and can grow in water as deep as 6 feet. Many property owners have used this grass to control shore erosion but here is where it has causes problems for others. As on land, it grows very quickly. Spreading across shallow waterways making them unnavigable. It has caused problems with irrigation systems, stream flow, and flood control in some areas. It has also invaded citrus groves and gold courses.
So how do we deal with this plant if it is on our property?
Torpedo Grass Photo Credit: Graves Lovell, Alabama Department of Conservation & Natural Resources, www.bugwood.org
Well, we know it is not a fan of cold weather, but we are in Florida; even north Florida is suitable for it. We know it will not survive extreme hot periods. We can only hope that it will get warm enough to knock back large acres of this thing; but warm temperatures like this are not good for most plants in our area – or animals for that matter. There are no known biological controls at this time. So that means we turn to herbicides.
Experience has shown that herbicides alone will knock it back, but rarely eradicates it from the area. Chemicals that have had success are glyphosate and imazapryl. In both cases, an aquatically registered surfactant may be needed for good results. When the torpedo grass is in water, herbicide treatment can be a problem. First, the chemicals used are non-selective and may kill plants you do not want to lose. Second, mats of dead torpedo grass have been known to decrease dissolved oxygen levels (due to decomposition) to levels where fish kills can occur. Some studies have found that burning a field of torpedo grass and then treating with both glyphosate and imazapryl has had some success. Treating first and then burning has not been as successful, nor has leaving one of the three out of the program.
As common and aggressive as this grass is, you may feel any attempt to control is feudal, but doing nothing can be very costly as well. We recommend properties with patches of this grass begin treatments soon, and if you have very little – remove as soon as you can. To learn more visit one of the following websites:
Torpedo grass in Aquatic Environments
Torpedo grass Management in Turf
