There are numerous insects and insect relatives that can produce webbing, and webbing can be a sign that something unwanted is near. Arachnophobes might grow uneasy at the sight of a spiderweb, and gardeners might frown to see the tiny filaments that spider mites spin. Tree lovers might assume that webs on a tree are a sign that caterpillars such as the eastern tent caterpillar have taken up residence. But what about webs on a tree trunk?
Bark louse webbing. Photo courtesy of Evan Anderson.
If you come across a tree trunk coated in silk, chances are you’re looking at the work of a bark louse. Also known as psocids or tree cattle, these little insects eat all the stuff that sticks to a tree’s bark. Lichen, moss, algae, and dead bark can all end up as meals for a hungry bark louse. The good news is that while lichens don’t hurt trees, neither do bark lice!
Bark lice spin their webbing as protection from predators. They often produce large quantities of webbing, because there are often large quantities of bark lice present. The name ‘tree cattle’ comes from the fact that they form these large colonies, and move in a manner similar to cattle in groups. While swirling swarms of creepy-crawlies rarely make people feel at ease, don’t worry about these. Acting as a sort of clean-up crew, they will do their work, grow and mature, and move elsewhere by themselves.
There are often several generations of bark lice each year in Florida, so they may reoccur. No control is needed for these insects, though if leftover webbing is considered aesthetically unpleasing it can be removed by spraying with a sharp jet of water. For more information about bark lice, see our EDIS publication at https://edis.ifas.ufl.edu/publication/IN553.
Bark louse nymph. Photo courtesy of Evan Anderson.
It is late summer and many of us enjoy being outdoors in the landscape and taking early morning walks before the temperature rises for the day. There are precautions to take while being outdoors and the activities as many insects are very active, including the yellow jacket. Late summer and many of us being outdoor brings us increases the change of being stung by this insect. The Yellow Jacket sting can be painful and potential dangerous to certain individuals with strong reactions to stings.
Yellowjackets are pollinators and eat caterpillar pests! Credit: Whitney Crenshaw, Colorado State University, Bugwood.org
In the State of Florida there are two species of this Yellow Jacket Wasp, the Eastern Yellow Jacket and the Southern Yellow Jacket. It is difficult to distinguish between them and for this article I will refer to them as Yellow Jackets. Yellow Jackets most often colonize in the ground and are often found in lawns that tend to stay dry, landscape beds and edge of woodlands. Colonies of this flying insect can grow into hundreds or even larger numbers. Often by observation in morning or evening light the entry and exit point of the nest can be see with some luck. It looks like an extremely busy airport with lots of landings and departures. The unfortunate way to find the nest can occur by mowing the lawn disturbing the nest with many yellow jackets emerging from the nest to protect it. The colony quickly goes into defense mode with vibrations occurring nearby. This has occurred with me on more than one occasion. All modesty can be lost while run away from the nesting area with several yellow jackets stinging you move quickly move away. Clothing has been known to be shed to hopefully remove the yellow jackets busily stinging either under or on the outside of clothing.
Southern yellowjacket, Vespula squamosa (Drury), nest dug from ground.
Credit: Gerald J. Lenhard; http://www.insectimages.org/
During the early part of the spring and summer season yellow jackets are busy foraging for protein sources to feed to queen and young larvae. During the consuming of the insects, with many of those harvested being harmful insects to plants. The yellow jackets derive their sugar sources from the larvae secretions as they consume the proteins provided. This is part of the reason we do not often see Yellow Jackets in late spring and early summer. As the queen begins to reduce the amount of egg laying, hence the less numbers of larvae to feed and harvest the sugar for a wasp population at its peak creates a more aggressive need to find alternate sources of sugar. This is part of the reason why yellow jackets show up in greater numbers at outdoor sporting events and other places to look for additional sugar sources. Sugar water for hummingbirds is another backyard site for yellow jackets to work hard for the sugar. Even the birds are careful about approaching the feeders.
I do not advocate the destruction of yellow jacket nesting sites unless they are in proximity to human activity as this can set the situation of stings and potential health challenges for people. If you identify a nest location do not approach and call a company that specializes in addressing these types of stinging insects. Keep in mind that this insect provides a benefit in harvest of many harmful pests to plants yet do pose a potential threat. Be observant as you garden situations that seemed fine last month may have changed quickly.
Summertime is known for cookouts, barbeque, a stroll through the park or even in your backyard; Be aware of stinging insects. These pests are especially active during the second half of summer and early fall when the colonies forage for food to sustain their queens during the winter. Although many are beneficial pollinators they often pose a danger because of their sting. While some of these stings causes minor reactions, others can pose a serious heath threat, which makes them medically important. These stinging hymenopterans includes wasps, hornets, yellow jackets, velvet ants, Africanized and European honey bee and fire ants.
Unique /Important Traits of this group of insects.
Photograph by Lyle Buss, University of Florida
Yellow jackets, paper wasps, and bald-faced hornets can sting multiple times causing allergic reactions. The female velvet ants have a very potent sting that has earned them the nickname “cow-killer.” Unlike Wasps, hornets, and yellow jackets, honey bees only sting once and lose their barbed stinger killing the bee within minutes talk about a sacrifice. Africanized honey bees are dangerous stinging insects that have been known to chase people for over quarter of a mile once they get excited and aggressive, earning the name “killer bee”. Imported fire ants both bite and sting repeatedly, and envenomation (injecting venom) only occurs through the sting.
Solitary vs. Eusocial Most wasps and bees are solitary – being alone or in solitude, and do not defend their nests, but will sting in defense if caught. On the contrary, the eusocial group, especially ants, bees, and wasps, will display territorial behavior and it is mostly these groups that cause medically significant stings.
Photograph by James L. Castner, University of Florida
What makes Hymenopterans important medically? Unlike the male, the female Hymenoptera possess specialized stinging apparatus used to inject their venom into prey’s or intruder’s body. Entomologist Justin O. Schmidt’s knows about this all too well, he records his own experience of venomous stings and rate it on a pain scale index ranging from 1- 4, with four being the most painful. It could be life-threatening for people sensitive to the venom. While most stings cause only minor problems, stings cause a significant number of deaths.
What are some possible reactions after the stings? Local reactions (pain, small edema, redness at the site of the sting); regional reactions, (extensive local swelling, exceeding 10 cm, persisting longer than 24 hours). Systemic anaphylactic responses – most dangerous of the reactions. Symptoms may include itching, rashes or hives, tightness or swelling in the throat, stomach pain, nausea and vomiting and dizziness. More severe cases the individual may experience severe shortness of breath, a drop-in blood pressure, loss of consciousness. Even though some of these reactions are mild about 3% of people ends up the emergency room each year from symptoms related to stings. Some may result in death of the individual.
Treatment/ Preventative Measures What to do? Capture the organism, if possible, for identification; allergy desensitization shots; sting removal; hive removal (certified handler); antihistamine (oral or parenteral) and epinephrine by inhalation or epinephrine by injection.
For more information, please contact your local county extension office. Supporting information for this article can be found in the UF/IFAS EDIS publications/websites below: Differences Between European and African Honey Bees: IN784-9221465.pdf (ufl.edu); Stinging or Venomous Insects and Related Pests: IG099-D1czi7xu65.pdf (ufl.edu) ; https://www.ncbi.nlm.nih.gov/pubmed/17265905 https://extension.entm.purdue.edu/publichealth/insects/stinging.htm
Biological control is a pillar of integrated pest management. It may seem a bit daunting the principle is simple. All things in nature have predators including insects. Biological control is simply building a conducive environment for the predators of undesired pests. One animal not often thought of in this capacity is bats. Insectivores by nature, these underutilized creatures have a big impact to your open spaces. Their steady diet of moths (Lepidoptera), beetles (Coleoptera) and flies (Diptera, which includes mosquitoes) reduce insect pressure to your gardens and landscaping.
I know what you are thinking. How effective can they possibly be? Pregnant females consume up to two thirds of their body weight through the summer months while rearing pups. Bats are small but keep in mind that these are not solitary animals. In south Texas, a single large colony consumes enough insects to save cotton farmers an estimated $741,000 per year in insecticides. That is just to illustrate the point as you won’t be able to attract huge colony. There is no reason to believe a smaller colony will not provide similar services in your gardens.
Habitat
Now that your interest is piqued, how can you attract bats to your property? Installing a bat house is the easiest way. They are typically a two foot by one foot structure holding single or multiple chambers in which bats roost. It provides shelter from predation and weather while providing a place to rear pups. Though commercially available they may be built at home with minimal cost. Place the bat house in a location with morning sun at least 12 feet off the ground. Ensure there is enough airflow around the house to keep them cool, but that the structure is watertight. Mount houses on poles next to buildings and you’ll have better success attracting residents. With everything in place, it is time to discover who will most likely be your new neighbor.
photo: Joshua Criss
The Bats of North Florida
Florida is home to 13 species of bats statewide. Of these, 11 may be found in the Panhandle but only 3 are common enough to be routinely seen. The Brazilian free-tailed bat (Tadarida brasiliensis) is the most common. Medium sized with brown fur, they have a long tail, wrinkled cheeks, and roost in man-made structures.
Photo: IFAS
Second most common are Evening bats (Nycticeius humeralis). These dark brown to yellow bats have short ears with a broad hairless muzzle. They are tolerant of other bat species often roosting in tandem with them.
Photo: IFAS
Finally, the panhandle is home to Southeastern Myotis (Myotis austroriparius). Easily the smallest of these bats, they are dull gray to brown with a lighter belly and long hairs between their toes. This species is the bat most likely to eat mosquitoes.
Photo: Jeff Gore, FWC
Finally, the panhandle is home to Southeastern Myotis (Myotis austroriparius). Easily the smallest of these bats, they are dull gray to brown with a lighter belly and long hairs between their toes. This species is the bat most likely to eat mosquitoes.
A Word of Caution
No article on wildlife would be complete without a word of caution. Bats are wild animals and should be treated as such. Never touch a bat on the ground as it most likely is not healthy. Bats do not generally cause issues but have been known to be disease vectors. Call a professional to collect the animal and never bring it into your home.
Bats can be a wonderful tool in controlling pests on your property. Creating habitat can help reduce pesticide need and cost to the homeowner. For more information on bats, see this Ask IFAS document, or contact your local extension agent for additional information on this and any topic regarding your gardens and more.
Having trouble with flea beetles? Tired of them showing up unannounced? Do not be alarmed here are a few tips to get rid of the unwanted guest in your garden.
Description: Flea beetles vary in appearance, where colors range from black to tan, with other, brighter colors mixed. They may also have a solid, striped, or spotted pattern depending on the species. Beetles are tiny with large hind legs which allow them to jump like fleas when disturbed.
Lifecycle: These unwanted guests will overwinter as adults in the soil or beneath plant debris and become active in early spring when temperatures reach 50°F, and begin feeding on weeds or early-planted crops. Eggs are laid by adult flea beetles normally around May in the soil or at the base of host plants. After 7-14 days eggs will hatch and larvae will feed and develop on various plant parts. They pupate in the soil for 11-13 days before emerging as adults.
Host plants: Some species attack a wide range of plants, while others target only certain plant families. (Table 1). In the garden, several vegetable crops are eaten by these pests, particularly those in the Brassica family.
Table 1: Common flea beetles and host plants.
Scouting: Adult flea beetles are particularly active on warm, sunny days. To identify damages, scout every 1-2 days in newly planted fields, since it is easier to identify the damages than to see the beetles themselves. Flea beetle populations can be monitored with yellow sticky traps.
Damage: Adult beetles feed on foliage, producing shot holes in the leaves, especially new leaves which will have a lacy appearance. Additionally, in leafy crops like lettuce or spinach, the holes can reduce the quality of the leaves.
Photo Credits: Jeffery Hahn University of Minnesota
Photo Credit : Jeffery Hahn University of Minnesota.
Management / Control strategies:
In the spring delay transplanting or planting by a couple weeks if possible.
In the fall, till the garden to uncover any hiding flea beetles.
Plant “push” or repellant crops such as catnip, sage, mint, hyssop, nasturtium, and basil.
Use a “trap crop” such as radishes, taking the pest’ focus off more valuable plants.
Dusting leaves with plain talcum powder repels flea beetles on tomatoes, potatoes, peppers, and other plants.
Insecticides may be used early in the season.
Water deters adult flea beetles. Any watering should be done in mid-day.
Planting after adults have emerged or crop rotation can help minimize flea beetle damage.
Apply commercially available nematodes that feed on flea beetle eggs, larvae, and pupae.
Recently, I’ve been asked about a deer fly trapping method that I wrote about a number of years ago. So, here it is. This aggravating insect is active now.
Deer flies, which are in the horsefly family, are annoying as they repeatedly and persistently dive for their victims until they inflict a painful bite.
Dr. Russ Mizell, now retired UF/IFAS Extension entomologist, experimented with a method to trap this insect. Mizell wanted to identify the optimum shape, size, color and speed to attract deer flies. If successful, he could temporarily remove a deer fly population long enough to enjoy an outdoor gathering without being bothered by deer flies.
Mizell said he started the research as a high school science project with his son but “it got so interesting, I just kept doing it.”
Deer flies wait for prey to walk before attacking. So, they are highly attracted to movement.
With this in mind, Mizell and his son decided the best way to snare deer flies was to “troll” for them from a slow-moving vehicle. Working in spring and summer when deer flies are most prominent, they set out to discover what kind of trap worked best.
They built a test platform on the hood of their vehicle that could troll seven different shapes at once. They ambled along in deer fly-infested countryside for set periods of one to five minutes, testing pyramids, squares, balloons, plant containers and other shapes, all coated with Tanglefoot (commercially available sticky spray for insects), then counting immobilized prey. They tried black, tan, blue and shapes of other colors suspended from various heights.
The trap that enticed the most deer flies proved to be a 6-inch flowerpot painted bright blue and coated with Tanglefoot. This trap captured as many as 30 deer flies in a one-minute test. It worked best when suspended three to six feet above the ground and trolled no faster than 10 feet per second or about 7 miles per hour.
The traps are remarkably effective, Mizell said. “Many times, after running the traps through an area, we found there were no deer flies left,” he said. “You trap them out for a short period until they repopulate the area.”
The traps also work when attached to a baseball cap and trolled by the hat’s wearer. But instead of attaching a flowerpot to your cap, you could attach a blue drink cup painted with Tanglefoot.
Despite its effectiveness, its aesthetic appeal leaves something to be desired.
