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 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 Sheila Dunning | Jan 20, 2017
4H youth assist an IFAS Extension agent in planting a tree. July 2008 IFAS Extension Calendar Photo. 4H children planting a small tree. 4H Club, youth groups, planting. UF/IFAS Photo: Josh Wickham.
Florida has celebrated Arbor Day since 1886 and has one of the first Arbor Day celebrations in the nation, on the third Friday in January. Trees establish a root system quickly when they aren’t expending as much energy on leaf development. So in Florida that is in the winter months; hence the reason for a January date for Arbor Day. However, installation anytime between October and March are suitable for most tree species. Palms are the exception. They require warm soil in order to root, so it best to plant them from April to August.
Planting and establishing trees is all about managing air and water in the soil. Three of the most common causes of poor plant establishment or even death include installing too deeply, under watering, and over watering. By selecting the appropriate species for the site, planting it at the correct depth, and irrigating properly trees should establish successfully. As simple as that sounds, many trees fail before they ever mature in the landscape.
Here are the ten steps to proper tree planting:
- Look up for wires and lights when choosing a site. Make sure that the location is more than 15 feet from a structure. Call 811 for underground utilities spotting at no cost.
- Remove any synthetic or metal materials from the top of the root ball.
- Find the topmost root (where the trunk meets the roots) and remove root defects, such as encircling roots. Loosed the root ball.
- Dig a shallow container-sized hole.
- Carefully place the tree in the hole. Don’t damage the trunk or break branches.
- Position the topmost root 1-2 inches above the soil grade.
- Straighten the tree. Be sure to check from two directions.
- Widen the hole to add backfill soil.
- Water to check for air pockets and hydrate the root ball. Add 3-4 inch thick layer of mulch at the edge of the root ball, with little to no mulch on top of the root ball.
- Prune for structural strength and damage removal. Stake if necessary in windy areas or if required by code.
These are probably not the steps used by previous generations. Twenty years of research has improved the techniques required for tree survival. Every year more and more trees are removed from storm damage, pest infestations, and development. Winter is time to add them back to both the urban and rural environments. Celebrate Arbor Day. Plant a tree. But, install it properly. Give your grandchildren the opportunity to enjoy it well into their adulthood.
by Sheila Dunning | Dec 5, 2016
Throughout history the evergreen tree has been a symbol of life. “Not only green when summer’s here, but also when 
it’s cold and dreary” as the Christmas carol “O Tannenbaum” says. While supporting the cut Christmas tree industry does create jobs and puts money into local economics, every few years consider adding to the urban forest by purchasing a living tree. Native evergreen trees such as Redcedar make a nice Christmas tree that can be planted following the holidays. The dense growth and attractive foliage make Redcedar a favorite for windbreaks, screens and wildlife cover. The heavy berry production provides a favorite food source for migrating Cedar Waxwing birds. Its high
salt-tolerance makes it ideal for coastal locations. Their natural pyramidal-shape creates the traditional Christmas tree form, but can be easily pruned as a street tree. Two species, Juniperus virginiana and Juniperus silicicola are native to Northwest Florida. Many botanists do not separate the two, but as they mature, Juniperus silicicola takes on a softer, more informal look. When planning for using a live Christmas tree there are a few things to consider. The tree needs sunlight, so restrict its inside time to less than a week. Make sure there is a catch basin for water under the tree, but never allow water to remain in the tray and don’t add fertilizer. Locate your tree in the coolest part of the room and away from heating ducts and fireplaces. After Christmas, install the Redcedar in an open, sunny part of the yard. After a few years you will be able to admire the living fence with all the wonderful memories of many years of holiday celebrations. Don’t forget to watch for the Cedar Waxwings.
by Sheila Dunning | Jun 3, 2016
According to the Atlas of Florida Vascular Plants, there are more than 4,200 plant species naturally occurring in the state. Nearly 3,000 are considered native. The Florida Native Plant Society (FNPS) defines native plants as “those species occurring within the state boundaries prior to European contact, according to the best available scientific and historical documentation.” In other words, the plants that grew in natural habitats that existed prior to development.
Native plants evolved in their own ecological niches. They are suited to the local climate and can survive without fertilization, irrigation or cold protection. Because a single native plant species usually does not dominate an area, there is biodiversity. Native plants and wildlife evolved together in communities, so they complement each other’s needs. Florida ranks 7th among all 50 states in biodiversity for number of species of vertebrates and plants. Deer browse on native vines like Crossvine (Bignonia capreolata), Trumpet Creeper (Campsis radicans), Yellow Jessamine (Gelsemium sempervirens) and Trumpet Honeysuckle (Lonicera sempervirens). The seeds and berries of Black-eyed Susan (Rudbeckia fulgida), Flowering Dogwood (Cornus florida) and Dahoon holly (Ilex cassine) provide vital food for songbirds, both local and migratory. Saw palmetto (Serenoa repens) provides cover for numerous birds and small mammals, as well as, reptiles.
Non-native plants become “naturalized” if they establish self-sustaining populations. Nearly one-third of the plants currently growing wild in Florida are not native. While these plant species from other parts of the world may provide some of the resources needed by native wildlife, it comes at a cost to the habitat. These exotic plants can become “invasive”, meaning they displace native plants and change the diverse population into a monoculture of one species. Chinese privet (Ligustrum sinense), Popcorn trees (Triadica sebifera) and Cogongrass (Imperata cylindrica) have changed the landscape of Florida over the past decade. While Water hyacinth (Eichhornia crassipes) and Hydrilla (Hydrilla verticillata) have changed water flow in many rivers and lakes. These invasive species cost millions of taxpayer dollars to control.
By choosing to use native plants and removing non-native invasive plants, individuals can reduce the disruptions to natural areas. For more information one specific native plants that benefit wildlife go to: http://edis.ifas.ufl.edu/uw384
It learn which plants are invasive go to: http://www.fleppc.org/list/2015FLEPPCLIST-LARGEFORMAT-FINAL.pdf
