Florida beekeepers are on high alert as the invasive Vespa velutina hornet poses a threat to honey bees, prompting vigilant monitoring to safeguard against potential impacts. Photo by Danel Solabarrieta, licensed under CC BY-SA 2.0.
A concerning discovery has emerged in Savannah, Georgia, regarding the yellow-legged hornet, commonly known as the “murder hornet’s cousin.” Officially identified as Vespa velutina by the Georgia Department of Agriculture in August 2023, it was first encountered by a beekeeper in the area.
The size of a nickel, Vespa velutina has distinctive black and yellow coloring with yellow/white legs. Photo by Gilles San Martin, licensed under CC BY-SA 2.0.
Although distinctive from the infamous “murder hornet,” the yellow-legged hornet, initially confirmed in Vancouver and the neighboring Whatcom County in Washington state, both hornet species pose threats to honey bee larvae and adults.
Approximately the size of a nickel, Vespa velutina features distinctive black and yellow coloring with yellow/white legs, earning it the nickname “yellow-legged hornet.” The discovery of the yellow-legged hornet has therefore spurred proactive measures to prevent its establishment in Florida and the rest of the United States.
The invasive nature of the yellow-legged hornet, originating from Southeast Asia and first appearing in Europe in 2004, poses a significant threat to beekeepers. This is due to its status as a generalist predator with honey bees as a primary target, intensifying concerns within the beekeeping industry.
The life cycle of the yellow-legged hornet begins with a single queen establishing a nest, laying eggs, and awaiting the emergence of workers. Nests can be found in various locations, growing to an average of 6,000 individuals. Predation on honey bee colonies increases during the summer months, with the hornets mating later in the year. The annual life cycle concludes with the death of all workers and males, and new nests are constructed in the following year.
Vespa velutina secondary nest, with adult hornets huddled together warming up in the sun. Photo by YVO-Photos, Adobe Stock.
Remarkably, a single mated female has the potential to initiate a new colony. Primary nests, starting as small as a tennis ball, undergo significant expansion. Secondary nests, reaching heights of up to one meter and containing over 17,000 cells, are typically situated at altitudes of 60 to 70 feet, making them challenging to access. A single hornet nest has a voracious appetite, as it can consume up to 25 pounds of insect biomass in a single season, underscoring the ecological impact of yellow-legged hornet colonies.
As a predatory wasp, the yellow-legged hornet feeds on a variety of arthropods, displaying opportunistic behavior, including feeding on decaying animals. While the ecological impact is not fully understood, DNA in the gut of hornets shows that they feed on other wasps, bees, butterflies, moths, and spiders. However, honey bees, particularly Apis mellifera, are preferred targets, posing a significant threat to the beekeeping industry. Reports from Europe suggest that up to 30 percent of honey bee hives are weakened by attacks, with approximately five percent facing complete destruction.
A male Vespa velutina, which exhibits longer, thicker antennae compared to females and, in line with all Hymenoptera males, lacks a stinger. Photo by Gilles San Martin, licensed under CC BY-SA 2.0.
Initially attracted to the honey bee hive by hive pheromones, yellow-legged hornets position themselves away from hive entrances, waiting for returning foragers, resulting in a “carpeting” of workers at the entrance. This term refers to the clustering or accumulation of honey bee workers near the hive entrance as they attempt to defend against the invading hornets. This behavior unfortunately leads to decreased colony production.
It’s essential to note that there are many domestic species, native to the United States, that closely resemble the invasive hornet but do not pose a threat to honey bees; in fact, many of them are valuable pollinators. The USDA has a photo gallery of these lookalikes, which can be accessed by visiting www.aphis.usda.gov and searching for ‘yellow-legged hornet.’
Vigilance from the public is crucial in minimizing the potential impact of Vespa velutina on honey bee populations in Florida and beyond. Photo by Danel Solabarrieta, licensed under CC BY-SA 2.0.
While the yellow-legged hornet can easily be confused with other hornets that are not problematic to honey bees, residents who believe they have identified Vespa velutina are encouraged to call the FDACS hotline at 1-888-397-1517.
If a sample is collected or a clear photo of the suspected hornet is available, please email dpihelpline@fdacs.gov along with location information to facilitate monitoring efforts. Vigilance and cooperation from the public are crucial in minimizing the potential impact of the yellow-legged hornet on honey bee populations in Florida and beyond.
The mercury is starting to rise, and the days are getting sunnier. Likely, you are beginning to or have been fantasizing about the potential of your landscape. Visions of multicolored flowers or rows of vegetables lined up waiting to be picked are synonymous with these visions, but they are not free from planning or work. You are not the only one waiting and hoping your gardens become flush with flowers. A veritable army of insects are looking to your landscape for their next meal. Some of these are good, providing critical pollination services, but some seek only to devastate your plants by consuming the leaves or sucking the sap out directly. It’s important to know who these culprits are and to understand the strategies within integrated pest management used to overcome or avoid the damage they bring.
Aphid nymph UF/IFAS Photo: J. Criss
The Bad Guys
First, let’s examine the perpetrators. Insects, like all subdivisions of animals, come in many forms. Those seeking to feast on your plant life are herbivores. They cause damage in several ways, and to understand them, a gardener should start by understanding the mouthparts of these creatures. Damage from chewers such as the Eastern Lubber Grasshopper (Romalea microptera) will be obvious as parts of the leaves will be skeletonized or left with large holes. Others are much more subtle, utilizing hypodermic-style mouths to remove the sugary photosynthates. The damage caused by these insects is much more subtle. It may present as pathogenic, including but not limited to misshaped or discolored leaves, damaged buds, fruit drops, and blackened leaves from sooty mold (Capnodium citri). Insects in this category include stinkbugs (Pentatomoidea) and aphids (Aphidodea). At this stage, you’re probably convinced that gardening in Florida is pointless, but have no fear; there are strategies to overcome these threats.
Scouting
Defending your gardens and landscapes begins with scouting. It seems very simple, but getting into your gardens daily will alert you to burgeoning issues well before they become major concerns. Get out there and look through stems, on the undersides of leaves, and for discoloration. It is much easier to remove leaves covered with stinkbug eggs than the adults once they’ve hatched.
Southern Green Stink Bug eggs UF/IFAS Photo: James Castner
First Steps
Next, investigate your gardening practices. Keep plants stress-free with appropriate fertilization and irrigation; these plants will fare better with any insects escaping your scouting efforts. Remove stressed and diseased plants as well as any which have been harvested. This will deny habitat to herbivorous insects. These combined practices are collectively known as cultural controls and are among the best for preventing insect issues. Any insect still appearing through these controls may be removed by hand. This is considered a mechanical control and is the least environmentally taxing, though it is the most labor-intensive methodology.
Ask Nature to Help
Biological controls are next in this hierarchy. Although they may seem confusing, they are nothing more than letting nature take care of itself. This article focuses on herbivores, but the insect world is diverse and includes predatory species. Creatures such as ladybugs (Coccinellidae) and lacewings (Chrysoperia sp.) actively hunt and consume those pests in your gardens, keeping you from this task. This method is not limited to Insects. Numerous animals, such as frogs, birds, nematodes, and even household pets, can fill this role. Fungi and bacteria have also been found to fill this role, as anyone who has applied Bacillus thuringiensis, commonly called BT, has discovered. This control method is the most environmentally friendly and involves the least amount of physical labor.
Green Lacewing UF/IFAS photo
Chemical use in Landscapes
Finally, chemical controls are a viable method to control insects in your landscape. These should be used as a last resort when the controls listed above are just not working. When used, make sure you follow the label provided on the product you’ve purchased and that it is the appropriate product designed to control your specific pest. The concern with this control is that pest species may adapt to the chemical, thus rendering it ineffective. When applied, ensure it is done minimally, both in volume and across square footage thus minimizing risk to off-target species.
Controlling pests in your garden can seem a daunting task. The multipronged approach utilizing the above control methods is known as integrated pest management. Following this methodology will keep your plants pest free and your landscape healthy. For more information on integrated pest management, see these Ask IFAS documents, or contact your local extension agent for additional information on this and any topic regarding your gardens and more.
A mole cricket has a face only a mother could love. They are so strange looking, in fact, that in the past week I’ve had two people ask me what they were. They have large, round, helmet-like heads, undersized eyes, and massive front claws used for digging. Unlike your garden-variety crickets, which really don’t cause any major damage to home landscapes, the mole cricket is quite the turfgrass menace. Instead of hopping about aboveground, they tunnel beneath the lawn and feast on the roots and leaves of grass, often destroying entire yards. They are also vegetable pests, going after tomatoes, cabbage, and peppers.
A young mole cricket. Its round head and large front claws distinguish it from other cricket species. Photo credit: Lucy Adams StevensonA) Horizontal and B) vertical view of a generalized tawny mole cricket burrow showing 1) horn, 2) 1st constriction, 3) bulb, 4) 2nd constriction, 5) turn-around, 6) surface tunnel, and 7) deep tunnel. Figure 1 from Nickerson et al. 1979. Ann. Entomol. Soc. Am. 72(3):438-440.
Mole crickets spend most of their time below ground and form burrows for hiding, laying eggs, and traversing through their territory. In mating season, males create a monotone song that averages 88 decibels—as loud as a motorcycle! The call comes from their burrows, which have funnel-like openings that expand at the surface, creating amplification comparable to a horn.
Beneficial larra wasp parasitizing a tawny mole cricket. Photo credit: UF IFAS
The tawny mole cricket (Neoscapteriscus vicinus) is the most common to our area and is an invasive species from South America. UF IFAS has had a specific research program related to mole cricket management since the late 1970’s. One successful outcome of this program has been the introduction of a biological control species, the larra wasp (Larra bicolor). The wasp manages mole cricket populations by stinging and temporarily paralyzing crickets. A female will then deposit an egg into the mole cricket’s body. The cricket recovers and goes about its daily routine until the egg hatches, at which point the larval wasp feeds on and eventually kills the mole cricket. Along with the wasp and release of flies and a nematode that also manage mole crickets, the biocontrol methods introduced between the 1980’s and 2004 have resulted in a 95% reduction in mole cricket populations in north Florida.
If you are seeing mole crickets, you can attract larra wasps to your property by planting shrubby false buttonweed or partridge pea plants, which the wasps feed on. If you have serious damage from mole crickets, check out this thorough Mole Cricket Integrated Pest Management Guide, or contact the horticulture agent at your local county extension office to get a site-specific recommendation for management.
In the heat of the summer biting flies become very active during the day. Deer flies, horse flies, and especially yellow flies inflict a fierce bite on people and other animals. All three species are in the Tabanidae family, commonly referred to as tabanids. Like mosquitoes, female flies of these species require mammalian blood in order to gain the enzymes necessary to lay eggs.
The tabanids lie in wait under bushes and in trees until a host is sensed. The keen eyes of the flies are able to see their prey’s movement, but mammals also create scents and carbon dioxide, making them very easy to locate. The attacks begin at sunrise, lasts about three hours, fades through the heat of the day, and peaks again about two hours before sunset, lasting until the sun goes down.
Tabanids use their mandibles to cut through the skin like scissors, causing blood to flow. Anticoagulants in the fly saliva are pumped into the wound to keep the fluid coming while the insect sponges it up with its labella.
While blood loss and disease transmission are concerns, for most, the disturbing part of the attack is the painful bite! Many people experience other adverse effects that extend the agony.
So, what can you do? The use of insecticides is generally considered ineffective and/or economically unfeasible. Habitat manipulation is an important component to reducing populations. Tabanid eggs are laid in layers on vertical surfaces, especially on aquatic vegetation. Secretions from the adult fly protect the eggs from water damage. When the maggots hatch in 5 to 7 days they must remain in moist areas to survive.
Over the next few months, larvae feed on organic matter, crustaceans, earthworm, and insect larvae (including their own species), steadily growing larger. Once fully grown, the larvae move close to the soil surface to pupate. Within 2 days the process is complete. They will remain in the pupal stage for 2 to 3 weeks before emerging as an adult fly.
So, reducing breeding habitat in areas where people and animals spend their time is a possible management technique.
For those times when you want to be at these sites, a trap may help. Research has shown that blue cylinders (open side toward the ground) coated with sticky material and attached to slow-moving objects are effective at reducing the abundance of these flies.
So, get out the Tanglefoot™, spread it on a blue plastic cup, and hang it from a branch that’s moving with the wind. How about attaching one to the boat, tractor, or lawn mower?
If your personal image is less important than the pain of the bites, you may even consider putting the cup on your hat.
How many blissful summer days have been disrupted in Florida by biting or stinging insects? More than a few. Mosquitoes, fire ants, yellow flies, dog flies, no-see-ums, yellowjackets, and more all live in our area and are either gleefully happy to violently defend their territory or actively seeking people out as food. One more creature to add to the list, though it is technically an arachnid rather than an insect, is the chigger.
Chiggers, also known colloquially as red bugs, are the larvae of mites in the family Trombiculidae. They are difficult to see, even as adults, because of their diminutive size. They’re tiny. So tiny, in fact, that you may not be able to feel them even if they’re crawling all over you. They don’t seem to have any claustrophobia, rather enjoying the tightest spaces under clothing and spots where skin is thin and tender. This leads to bites in some very uncomfortable places. When they bite, chiggers temporarily attach themselves to their host and inject a digestive fluid into the skin. This triggers an immune response in people; our bodies don’t seem to like being partially digested and sucked up by tiny critters. Even if the body’s response means the mite doesn’t finish its meal, it still leaves a mark. Different people may have varying sensitivity to the bites, but it is never a pleasant experience. Itching sets in four to eight hours after the bites, which may be accompanied by red welts or bumps on the skin. Severe reactions may lead to fever.
Chigger. Photo Credit: University of Florida/IFAS
Chiggers do not attach themselves permanently to people, nor do they burrow under the skin. If you’re lucky enough to discover any mites still biting you, take a hot shower and lather with soap several times. Nail polish applied to the bites will not help, though strangely enough meat tenderizer may help with the itching. Antiseptic is always a good idea as well, and if you’re short on meat tenderizer, an over-the-counter anti-itch product will serve too.
To avoid running afoul of chiggers, be aware that they are most likely to be found in low, damp areas outdoors with shrubby vegetation. They may be found elsewhere, but one persistent myth is that they like to inhabit Spanish moss. In reality, they don’t have any particular attraction to it.
Thankfully, insect repellants that contain DEET repel chiggers as well as other pests. For maximum effectiveness on chiggers, apply repellants to sleeves and cuffs of pants, as well as waistlines.
