Q: Something is chewing off the ends of branches on some of my trees. I go out every morning and there are three or four more on the ground. The leaves are nice and green on the fallen branch. Is it squirrels or could it be something else?
A: What you are seeing is twig girdler damage. This is a long horned beetle (so named because his antennae’s are longer than his body). It is a pest of pecan and hickory, but may also attack persimmons, hackberries and other hardwood trees.
The nature of the girdle itself distinguishes the twig girdler from other branch pruners and why I can tell it’s not a squirrel. The cut by the twig girdler is the only one made from the outside of the branch. The cut end of the branch looks like mini beaver damage. Since the twigs are girdled while the leaves are present, the severed twigs retain the leaves for some time.
The adult beetles girdle twigs and small branches causing the ends to break away or hang loosely on the tree. It is not uncommon to see the ground under infested trees almost covered with twigs that have been cut off. The female lays her eggs in the tips of the branch then chews around the branch leaving a little wood attached in the center. This breaks off in the wind. If you look closely on the fallen branch you will see tiny holes where the eggs were laid. The holes will usually be by a bud scar or near a side shoot.
They aren’t hurting the tree unless you had a pecan orchard, then the loss of branch tips could reduce nut production in the following few years. Most girdled twigs are from 1/4 to 1/2 inch (occasionally up to 3/4 inch) in diameter, and 10 to 30 inches long.
The best control is to pick up the twigs and discard them as the larvae develop and pupate in them. Insecticide is rarely justified or practical.
(Editor’s note – squirrels can also clip off limbs but the cut ends will look chewed or broken)
Sharon Dowdy is a news editor with the University of Georgia College of Agricultural and Environmental Sciences
The tawny crazy ant has made its way into Georgia for the first time. University of Georgia Extension agent James Morgan of Dougherty County discovered the ant—which originates from South America—on Aug. 15 and submitted a sample to the University of Georgia for identification.
Tawny crazy ants, Danny McDonald, Texas A&M
Prior to his discovery, the ant was found only in a few counties in Florida, Mississippi, Louisiana and Texas. Where it occurs in those states, it is a major nuisance. Morgan stumbled upon the ants at an assisted living facility, after the director called the UGA Extension office for help controlling the insect.
Thousands travelling together
“What I found was thousands of dead ants in a pile in the corner of the bathroom floor,” Morgan said. “The duplex was vacant, and the ants had come in looking for a food source. When they came in, they died and we found hundreds of them piled up around baseboards and in corners.”
After further investigation outside the facility, Morgan found droves of the ants in an outbuilding. “We found them in the lawn on debris and dead wood, and we traced them back to a storage area that was full of appliances,” he said.
Accustomed to identifying Argentine ants, fire ants and other ants common to Georgia, Morgan knew these ants were different. “They’re reddish in color, very tiny, and they run around and scurry really fast. And they don’t march in a straight row like Argentine ants,” Morgan said.
Confirmed as tawny crazy ants
He sent a sample to UGA entomologist Dan Suiter, an Extension specialist in urban entomology housed on the UGA campus in Griffin. The samples were confirmed as tawny crazy ants (Nylanderia fulva) by taxonomist Joe MacGown at the Mississippi Entomological Museum.
The ant is classified as a nuisance because of its attraction to electricity and because it travels in masses. It likes to get into electrical boxes, Suiter said. Large accumulations of the ant can cause short circuits and clog switching mechanisms, which can result in electrical shortages in phone lines, air conditioning units, chemical-pipe valves, computers, security systems and other electrical locations.
“Most people will be overwhelmed by the number of tawny crazy ants they’ll find. It’ll be through the roof,” he said. “They’ll come in your house, and it becomes a kind of ‘ant from hell’ scenario.”
Suiter said once an ant species gets established, it’s “really hard to dislodge them.”
Not Argentine ants
He expects Georgians to confuse the tawny crazy ant with Argentine ants. Like Argentine ants, the tawny crazy ant travels indoors in search of food and water. It doesn’t sting like a fire ant, but it probably has a mild bite, he said. The ant also is capable of spraying small quantities of formic acid, which may irritate some individuals.
About one-eighth-of-an-inch long, tawny crazy ants are slightly larger in size than Argentine ants and have erratic foraging patterns. Argentine ants are dark brown in color, slightly smaller and do not move as fast or as erratically.
“We will probably get a lot of reports that people have it when they really have Argentine ants. Those are sugar ants—the ones you see in trails,” he said.
Suiter describes dead tawny crazy ants as looking like snowdrifts. “They can be inches deep in a pile,” he said. “When they get up and going, the numbers that die will be in the tens of thousands in and around a structure.”
Likely came to U.S. through a port
Like many non-native, invasive species, no one knows exactly how the ant came to the U.S. or how it made its most recent trip to the Peach State. “It probably came into the U.S., initially, from several Florida ports and one in Mississippi and one in Galveston,” Suiter said. He thinks the ant may have hitched a ride on a plant brought into the state from a region where the tawny crazy ant is already established.
Back in Albany, Morgan says the director of the assisted living facility had no knowledge of anyone traveling to any of those regions.
To discourage the new ant species and other pests from entering a home, Morgan recommends searching for and sealing any cracks around doors and windows. Due to large populations, the tawny crazy ant typically requires a pest management professional.
To verify the presence of tawny crazy ants, take a sample to the nearest UGA Extension office. For office locations, call 1-800-ASKUGA1 or see extension.uga.edu.
For some 50 years, scientists have tried — but failed — to find a way to use microbes as a means of biological control for destructive subterranean termites.
University of Florida researchers have now discovered why termites have proven to be so disease resistant. Termites use their own feces as nest-building material. The fecal nest promotes the growth of beneficial bacteria, which in turn suppress pathogens — or in plainer words: termite poop works as a natural antibiotic.
Besides improving termite control, the findings could help pave the way for new human antibiotics.
The study, published Wednesday in Proceedings of the Royal Society B, began about nine years ago, when postdoctoral associate Thomas Chouvenc, at the time a student, approached his faculty adviser, Nan-Yao Su, with his wish to study termite-pathogens interactions.
Su said he knew from the reams of scientific literature that biological control attempts in termites hadn’t been successful.
“Instead of saying ‘let’s use fungi to control termites,’ I said, ‘Maybe we could turn the tables around and ask ‘Why has it never worked?’” Su recalled.
Su, the inventor of well-known termite baiting system Sentricon, and Chouvenc are part of UF’s Institute of Food and Agricultural Sciences. Both are based at the UF/IFAS Fort Lauderdale Research and Education Center.
Termites are a $40 billion problem worldwide, and the Formosan subterranean termite accounts for a large portion of the problem.
The research team began to identify and isolate more than 500 strains of bacteria from five termite colonies collected from outdoor sites around Broward County. About 70 percent of the bacteria were shown to be active against a range of bacteria, yeast and fungi.
Researchers then honed in on a specific strain of bacteria called Streptomyces found in the nest material of all five termite colonies.
When they introduced a disease-causing fungus into sterile nest-like environments, they found that the fungus survived and killed the termites. When the Streptomyces bacterium was added to the nest, it protected the termites. When they tested a different bacteria strain against the fungus, it had little effect, leading them to conclude that the Streptomyces bacteria found in the nests may aid the termites by producing beneficial antimicrobial compounds, while feeding on the termite fecal nest.
Chouvenc said it was a time-consuming process but well worth the effort.
“We had to put all of the pieces of the puzzle together and show it was not just an artificial environment that produced this, that it does this in the individual termite nest, as well,” he said.
It is possible the team’s findings may help lead to new microbes that can be used to create new antibiotics for human use, Chouvenc said. Beyond that, he said, they want to tackle questions about how termites evolved to maintain their nests’ health, and whether it’s a stable system or one that’s constantly in flux.
If the termites are able to continually recruit the microbial strains they need to stay disease free, Su said, “then we have to find out how the termites do that.”
The research was funded by royalties Su receives, as well as seed money from UF/IFAS research. The other authors were Caroline Efstathion, a graduate student and employee in Su’s laboratory; and Monica Elliott, a UF/IFAS plant pathology professor also based at the Fort Lauderdale REC.
County and city officials in the Southeast spend millions of dollars each year to combat mosquitoes. But those costs are only a fraction of what Southeastern families spend to keep their furry family members safe from mosquito-borne parasites.
Each year Georgians spend between $9 million and $14 million treating heartworms in their dogs, said Elmer Gray, an Extension entomologist with University of Georgia Cooperative Extension. Dog owners across the country spend about $1.2 billion on heartworm prevention, and Gray estimates that about $40 million of that amount is spent in Georgia.
Those price tags dwarf the $7 million cities and counties in Georgia spend to keep mosquito populations under control and make heartworms the largest mosquito-related expense in the state.
“It really is the most expensive cost associated with mosquitoes,” Gray said.
Heartworm-related expenses are sometimes left out of studies calculating the economic impact of mosquitoes, but Gray believes these costs should be included.
“If it wasn’t for mosquitoes, there would be no dog heartworm problems,” Gray said. ”So consequently, the cost associated with heartworms – in my mind – is directly attributed to mosquitoes, thereby adding to the cost of dealing with this insect.”
He estimated the cost of prevention and treatment of heartworms with data provided by the UGA College of Veterinary Sciences and from Merial, a company that makes heartworm preventatives and other pharmaceuticals for animals.
The cost of preventative heartworm medicine is about $15 a month, and the cost of treating a heartworm infection can vary from between $600 and $1,000.
There are at least six species of mosquitoes that can transmit the heartworm parasite in Georgia. The flying insects pick up young heartworms, called microfilariae, when they feed on the blood of an infected animal. The microfilariae spend about two weeks maturing into larvae inside the mosquito, according to the American Heartworm Society.
When the mosquito takes its next meal, the larvae are deposited into the new host animal where they will mature into adult heartworms over the next six months.
Without treatment, the worms congregate around the right side of the heart and the arteries of the lungs where they can eventually cause heart or liver failure.
Dogs, cats and even humans can all be infected by heartworms, but the infections are most serious and most prevalent among dogs.
Southeastern states have the greatest prevalence of heartworm infections, and there’s an almost 100 percent chance that a dog living in Georgia will have the disease by age 5 if its owners don’t give it monthly preventive treatment, Gray said.
While cities and counties will continue to battle mosquito populations in Georgia, there is no way to reduce populations enough to prevent dogs and other animals from being infected with heartworms without medication.
“It would be impossible to prevent heartworm infections by controlling mosquito populations,” Gray said. “However, treating dogs with the proper preventative medicine is 100 percent effective at preventing the disease.”
Editor’s note – The recent bee kill in Oregon and the resulting statewide temporary restriction of one of the neonicotinoid insecticides highlights the need to be careful in timing neonicotinoid insecticide applications and using these pesticides safely.
Jonathan Larson is looking at ways that people can safely use insecticides and not affect native pollinators. Image – Katie Pratt, UK Agricultural Communications specialist
Many homeowners may grimace at the sight of grubs, caterpillars or other pests lurking in their lawns, but understanding when and how to apply an insecticide to control these pests could have a big impact on native pollinator populations, according to a researcher from the University of Kentucky College of Agriculture, Food and Environment.
Jonathan Larson, a UK doctoral student, has found that when neonicotinoids, a type of systemic insecticide, are applied to flowering lawn weeds that are frequented by native bees, such as dandelions and white clovers, the chemicals can negatively impact local pollinator populations.
While honeybee population decline has received much attention, bumblebee numbers have also been on the decline. Much like honeybees, bumblebee population decline is related to diseases, pesticides and habitat loss or fragmentation.
“With honeybee populations struggling, we need to rely on native bees, such as bumblebees, to pick up the slack on plant pollination,” said Dan Potter, UK entomologist and Larson’s adviser. “Many native bees are much more efficient at pollinating certain types of crops, like tomatoes, urban flowering plants and vegetables grown in home gardens.”
Larson’s research, published in the journal PLOS ONE, showed that exposure to clothianidin, a neonicotinoid insecticide, negatively affected queen production. It also slowed foraging and caused higher mortality rates in worker bees within five days after exposure at plots on UK’s Spindletop Research Farm compared to control hives. When moved to an untreated field to forage for six weeks, the bees had a hard time gaining weight compared to the controls. Bumblebees exposed to chlorantraniliprole, from a relatively new class of lawn insecticides, developed and reproduced normally compared to the control hives.
“We’re trying to figure out ways that people can safely use insecticides and not affect native pollinators,” Larson said. “One way may be for homeowners and commercial lawn care professionals to use the newer class of insecticide instead of a neonicotinoid to control common lawn pests. Another way could be mowing treated areas.”
He found that when clover flowers treated with an insecticide are removed by mowing and new flowers grew to replace them, neither insecticide adversely affected bumblebee colonies.
“Direct contamination of the flowers is the problem, so homeowners need to remove the flower heads of weeds either before or after applying an insecticide to prevent exposure to native pollinators,” Larson said.
Larson is now studying the level of insecticides present in the nectar of subsequent generations of clover flowers after the field has been treated with an insecticide and the treated flowers have been removed.
There are three types of fairy rings based on the symptoms they produce.
Type I. Grass is badly damaged or killed.
Type II. Grass growth is stimulated.
Type III. Grass growth is not influenced by the fairy ring. The only evidence of the fairy ring is the presence of fungal fruiting bodies.
The type III fairy ring symptoms are more predominant during prolonged periods of wet weather, while Type I and Type II fairy ring symptoms are common during hot, dry weather in the summer.
The most effective means for fairy ring control is to prevent the causal fungi from becoming established in the turf. It’s advisable to remove large pieces of woody material such as stumps, dead tree roots and other organic/woody debris before turf is planted to prevent the establishment of fairy rings.
Fairy rings thrive on organic matter; therefore, changing the organic content in the soil by spike/core aeration and thatch reduction can help to control fairy ring. Water and fertilize declining area inside ring appropriately to stimulate new turfgrass growth.
In golf course settings, the use of fungicides is an option to control fairy ring while corrective cultural measures are taken.
Rosmarie Kelly, Public Health Entomologist, Georgia Department of Public Health
The first step in controlling the mosquito species which are causing your client problems is to identify the local species. Quite often, not all methods of control will work well for all species. Knowing which species are the issue can help you determine future control methods.
So, how do you determine which species are active at any given time in your area? The best method is to set out light traps in the area, collect the mosquitoes, and identify them. If this is done in a systematic way, it is possible to develop a database of local mosquito species that will aid you in determining the best method of control at any given time.
Is this always feasible? Unfortunately, no. However, depending on where your client lives, some of this information may be available from other sources. Municipal mosquito control programs in Georgia rarely have sufficient funding to do mosquito surveillance. However, there are a few programs that do collect surveillance data and may be willing to share information.
The very least that should be done is to determine if the mosquito causing the problem is Aedes albopictus, the Asian tiger mosquito. Asian tiger mosquitoes are small, aggressive, day-biting mosquitoes with black and white striped legs.
Since they do not fly far from their breeding ground, Asian tiger mosquitoes can be controlled through a combination of source reduction (eliminating breeding sites) and barrier spray (application of pesticide to vegetation where mosquitoes rest). Not all mosquitoes will rest locally after biting, so barrier spray may not be as effective for all species but it works well for Asian tiger mosquitoes.
The most important reason to understand which mosquito species are causing problems at any given time is to assist with educating the client. People tend to believe that all mosquitoes are the same, and often have unrealistic ideas about their control. If you are well informed, it can help you when discussing control issues with the client and assist in keeping the client happy with your control program.
There are control situations that are better handled by commercial mosquito control companies. Having a list of local commercial applicators can be useful to a municipal program.
Resources are available to assist with mosquito surveillance and identification. Check out these sites:
The Georgia Department of Public Health has offered at least one mosquito ID course every year since 2002, and hopes to continue this tradition. The various mosquito control products vendors not only offer equipment calibration, they also offer training opportunities.
Severe leaf and crown rot, caused by Bipolaris sp. can occur in bermudagrass lawns, sport fields, or golf fairways. Initial symptoms of this disease include brown to tan lesions on leaves. The lesions usually develop in late September or early October. Older leaves are most seriously affected.
Under wet, overcast conditions, the fungus will begin to attack leaf sheaths, stolons and roots resulting in a dramatic loss of turf. Shade, poor drainage, reduced air circulation; high nitrogen fertility and low potassium levels favor the disease.
To achieve acceptable control of leaf and crown rot, early detection (during the leaf spot stage) is a crucial.
Large Patch
Large patch disease of turfgrass is most common in the fall and in the spring as warm season grasses are entering or leaving dormancy. Large patch is caused by the fungus Rhizoctonia solani. It can affect zoysiagrass, centipedegrass, St. Augustinegrass and occasionally bermudagrass.
Large patch disease is favored by:
Thick thatch.
Excess soil moisture and poor drainage.
Too much shade, which stresses turfgrass and increases moisture on turfgrass leaves and soil.
Early spring and late fall fertilization.
If large patch was diagnosed earlier, fall is the time to control it. There are a myriad of fungicides that can help to control the disease. Preventative or curative rates of fungicides (depending on the particular situation) in late September or early October and repeating the application 28 days later are effective for control of large patch during fall. Fall applications may make treating in the spring unnecessary. Always follow label instructions, recommendations, restrictions and proper handling.
Cultural practices are very important in control. Without improving cultural practices, you may not achieve long term control.
Use low to moderate amounts of nitrogen, moderate amounts of phosphorous and moderate to high amounts of potash. Avoid applying nitrogen when the disease is active.
Avoid applying N fertilizer before May in Georgia. Early nitrogen applications (March-April) can encourage large patch.
Water timely and deeply (after midnight and before 10 AM). Avoid frequent light irrigation. Allow time during the day for the turf to dry before watering again.
Prune, thin or remove shrub and tree barriers that contribute to shade and poor air circulation. These can contribute to disease.
Reduce thatch if it is more than 1 inch thick.
Increase the height of cut.
Improve the soil drainage of the turf.
See the current Georgia Pest Management Handbook for more information. Check fungicide labels for specific instructions, restrictions, special rates, recommendations and proper follow up and handling.
Spring Dead Spot of Bermudagrass
The causal agents of Spring Dead Spot (SDS) are most active during cool and moist conditions in autumn and spring. Appearance of symptoms is correlated to freezing temperatures and periods of pathogen activity. Additionally, grass mortality can occur quickly after entering dormancy or may increase gradually during the course of the winter. Spring dead spot is typically more damaging on intensively managed turfgrass swards (such as bermudagrass greens) compared to low maintenance areas.
Management of Spring Dead Spot
Practices that increase the cold hardiness of bermudagrass generally reduce the incidence of spring dead spot. Severity of the disease is increased by late-season applications of nitrogen during the previous fall.
Management strategies that increase bermudagrass cold tolerance such as applications of potassium in the fall prior to dormancy are thought to aid in the management of the disease. However, researchers have found that fall applications of potassium at high rates actually increased spring dead spot incidence. Therefore, application of excessive amounts of potassium or other nutrients, beyond what is required for optimal bermudagrass growth, is not recommended.
Excessive thatch favors the development of the disease. Therefore thatch management is important for disease control,
Implement regular dethatching and aerification activities.
There are several fungicide labeled for spring dead spot control.
Fall application of fungicides is essential for an effective control.
Weather conditions have been conducive for turfgrass diseases. We have received numerous calls and emails about proper control strategies, especially on the appropriate selection of turfgrass fungicides and their efficacy. Some ways to maximize the efficacy of turfgrass fungicides include:
Read carefully and follow the label directions before applying fungicide.
Apply fungicides at the rate specified on the label.
Always follow instructions for re-entry to the area.
Fungicides are not equally effective on all diseases. Proper fungicide selection is very important for disease management.
The best control is achieved by applying fungicides preventively (before disease is present).
Use compatible tank mixes at recommended label rates.
Use proper sprayer, nozzles and pressure to deliver appropriate coverage of fungicides. Flat fan or swirl chamber (raindrop) nozzles are recommended for turfgrass fungicide applications.
Avoid turfgrass stress (drought or temperature) before or at the time of application. This could interfere with maximum fungicide uptake, activity and efficacy.
Fungicides should be sprayed when air temperatures are between 60°F and 85°F (15°C and 29°C) for best results.
Fungicides should stay on the turfgrass foliage for at least 6 hours for most effective control. Delay mowing and other cultural practices as much as possible to give the fungicide a chance to work (for proper mowing frequency follow the one-third rule).
Use enough water when applying fungicides for adequate coverage. Usually 2.0 gal water/1000 sq. ft. should give adequate coverage and deposition. Some fungicides have to be watered-in for proper placement to ensure adequate activity.
Do not apply fungicides when conditions are windy to avoid drift and poor coverage. Wind velocity tends to be the lowest early in the morning and late in the afternoon.
Be patient if an application appears to have produced no results. Some fungicide application results can be seen months later.
Use fungicides judiciously and sparingly.
Some notes on Fungicide Resistance
Fungi sometimes develop resistance to particular fungicides, especially when a product is used repeatedly without alternating with chemically unrelated fungicides. When fungicide resistance develops, there is no value in increasing rates, shortening intervals between sprays, or using other fungicides with similar modes of action.
Fungicide resistance has been confirmed in a few instances for each of the following turfgrass diseases and fungicide groups:
Dollar spot against benzimidazole fungicides (thiophanate methyl) and DMI fungicides (propiconazole)
Gray leaf spot against strobilurin (QoI) fungicides (e.g. azoxystrobin, etc.)
Anthracnose against benzimidazoles (thiophanate methyl) and strobilurins (QoI) (azoxystrobin, etc.)
Pythium blight against phenylamide fungicides (mefenoxam)
Benzimidazoles (e.g. thiophanate methyl) and phenyl amides (e.g., mefenoxam) have the highest risk of resistance.
Strobilurins have a moderately high risk of resistance
DMIs and the dicarboximides (e.g. iprodione) have a moderate risk
Nitriles (e.g. chlorothalonil), aromatic hydrocarbons (e.g. PCNB), and dithiocarbamates (e.g. mancozeb) have a low risk of resistance.
Several general strategies are recommended to minimize the risk of fungicide resistance.
First, don’t rely on fungicides alone for disease control.
Avoid using turfgrass varieties that are highly susceptible to common diseases and follow good disease management practices.
Also, limit the number of times at-risk fungicides are used during a growing season and alternate at-risk fungicides with fungicides in a different chemical group (those with a different FRAC numeric code).
When using an at-risk fungicide, tank-mixing it with another fungicide from another chemical group (different mode of action) can also reduce the risk of resistance.
These are general principles that can help to reduce, but not eliminate risk. A fungicide-resistant pathogen population can still develop when these principles are practiced. Refer to product labels before tank-mixing products to ensure compatibility and to avoid phytotoxicity.
The Office of the Southern Regional Extension Forester, the USDA FS Region 8–Urban and Community Forestry Program along with the Southern Group of State Foresters have partnered to design, develop and implement a state-of-the-art online, distance-learning program geared specifically toward beginning urban foresters and those allied professionals working in and around urban and urbanizing landscapes
To access the modules for International Society of Arboriculture and Society of American Foresters credit, please visit www.cfegroup.org
To access the modules for volunteer credit or a certificate of completion, visit www.campus.extension.org and look for the eLearn Urban Forestry–Citizen Forester course.
For more specific information, please contact Sarah Ashton, Educational Program Coordinator, Southern Regional Extension Forestry at sashton@sref.info.
Jule-Lynne Macie, Rockdale County Extension Agent
