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.
Extended spring weather with cool nights and frequent rain can be enjoyable for humans, but does strange things to plants, especially if dormant fungi are hanging around. Exobasidium vaccinii is a fungus that is believed to overwinter as spores attached to bark and bud scales. It can cause infection with the opening of buds in spring, creating odd shaped leaves and flowers that are referred to as galls. Infection is dependent on high humidity and moisture during bud break. Gall growth is due to plant cell division resulting from the stimulus of hyphal growth within host tissue. When galls are still soft, the fungus grows between epidermal cells, breaks the cuticle, and sporulates giving the gall a white cast. Either all or part of a leaf may become thickened, fleshy, and covered with a white bloom of spores. At first, diseased leaves are succulent and white, but they later shrink into hard, brown, gall-like bodies. Galls are composed of fungus-infected plant tissue. Older leaves are resistant to infection. Exobasidium vaccinii is most common in azaleas and camellias.
Photo by Sheila Dunning
But, other Exobasidium species are floating out there, and with just the right conditions they can deform other plants. That’s what caused this odd formation on one flower of a gardenia plant. In this case, the spores fused the sepals to the petals of the flower.
Photo by Margaret Stewart
While chemical controls are available, they would need to begin before symptoms appear and continue until the gall dried completely. It may be an option for the fastidious weather watcher with a good working knowledge of this disease. But, for the rest of the population, removing and destroying galls before they turn white is the best management practice to avoid having spores form and hang around until next spring. Proper pruning of the plants to improve air circulation will also reduce the chances of favorable conditions, should there be an extended cool, wet season next year.
When to prune a particular shrub can be a confusing practice for even the most experienced gardener. Luckily there are many plant guides to help remind us of pruning times or even a quick call to your local Extension office.
Now that we finally remember the best time to prune azaleas or French hydrangeas, the nursery throws us a loop with everblooming plants. Although not new, the Encore® series of azaleas and Endless Summer® collection of hydrangeas have the wonderful characteristic of blooming repeatedly throughout the growing season. When is the best time for pruning these repeat blooming shrubs?
In general, if you select your Encore® azalea carefully, it should need very little pruning. There are many sizes available to fit every space. Reduce your need for pruning by choosing a selection that will not outgrow your space. For example, Autumn Sangria® is a larger selection to at least 4-5 feet tall while Autumn Embers® is about 3 feet tall. If your plant needs a little selective pruning, the best time to prune is still after the first initial big bloom in April.
Encore Sangria has vivid pink flowers. Photo by Beth Bolles, UF IFAS Extension Escambia County.
Pruning time for Endless Summer is the same for other mophead hydrangeas even though it blooms on both old and new wood. You may selectively prune after the first bloom. It is always fine to deadhead faded blooms back to the first healthy buds.
A typical crane fly on the outside of a building. Photo credit: Carrie Stevenson, UF IFAS Extension
All my life, I’ve known them as mosquito hawks. Built like extra-large, spindly-legged versions of mosquitoes, they look a bit intimidating. However, growing up we were told they were harmless and actually fed solely on mosquitoes. In the days before Google, I just accepted it as fact and was glad to see them around.
In early March, there was a bit of an invasion of these insects. I started seeing them everywhere outdoors and inside my office building. They are slow movers, bouncing in the air more than flying. After several days of seeing them everywhere, though, they pretty much disappeared.
Several crane flies appear to have met their demise inside my office building. Photo credit: Carrie Stevenson, UF IFAS Extension
Like much folk wisdom accrued through my life, the story of the mosquito hawk is not totally true. They are harmless, that much is correct. While many people do know them as mosquito hawks, the accepted common name is the crane fly. Crane flies come in a wide variety of sizes and colors, ranging as some of the smallest and largest species in the fly Order, Diptera. Their diversity is rather mind-blowing, with the Family Tipulidae including about 15,000 species of crane flies worldwide.
Crane fly larvae live in aquatic environments and feed on decaying plant material. Photo credit: North Carolina State University
As for being voracious predators of mosquitoes, we have no such luck. Crane flies barely eat at all, because their adult life span is as short as those two weeks I recently noticed them around. They spend most of their lives as aquatic larvae, living in streams, pond edges, and rotting vegetation. Adults do not have the right mouth anatomy to eat other insect prey, instead drinking only by sponging up water in dew form or taking nectar from plants. Their primary purpose in adulthood is to complete the mating process. Females lay eggs near water, hence the location as larvae. After this hedonistic spring break experience of adult life, they die.
Crane flies, in both larval and adult forms, are popular snacks for other wildlife. The adults are easy targets for birds and bats. The larvae, which in some species are as large as a pinky finger, are tasty morsels for fish and amphibians. During their larval existence, crane flies ingest debris, helping with the decomposition process and filtering the water bodies they live in. Despite their short life span, crane flies make an outsized contribution to the food web.
Zinnias are well-known annual flowers, primarily recognized for their easy and fast growth. Their wide range of growing habits contributes to their popularity, as they can range from short and bushy to tall with a singular stalk. Regardless of their growing habit, Zinnias are prolific bloomers. They belong to the aster family and are native to Mexico and Central America, thriving particularly well throughout the South.
Photo: De’Anthony Price
Zinnia Characteristics
There are three distinct types of Zinnias based on floral structure: single, double, and semi-double. The different floral structures do not necessarily correlate with plant habits. ‘Single’ refers to flowers that have only a single row of petals, with the center of the flower clearly visible. ‘Double’ Zinnias have multiple rows of petals, and the center is not clearly visible. ‘Semi-double’ cultivars exhibit a combination of traits, with flowers having multiple rows of petals while still maintaining a clearly visible center.
Pollinators and Zinnias
Zinnias are great for attracting pollinators, especially butterflies. Interplanting zinnias between rows of vegetables or as a border around vegetables is a great way to attract more pollinators to your garden. There are a few guidelines available for attracting butterflies to your yard using zinnias. The taller varieties are better than dwarf or compact cultivars, and those with wide, flat blooms provide a larger landing surface. Flowers should have prominent yellow centers (disc floret); double bloom varieties make it difficult for butterflies to access nectar. It is also possible that some varieties attractive to butterflies produce a larger quantity of and/or better-quality nectar than others.
Photo: UF/IFAS
Planting Zinnias
Zinnias perform better in garden beds than containers and, due to their ability to grow so quickly, can be direct seeded. To direct seed, the soil temp should be at least 70 degrees and plant the seeds at 1/4’” deep. Zinnias can also be planted as transplants and should be done once the soil warms to 60 degrees. Plant spacing can be anywhere from 8 to 12 inches depending on the plant’s habit. Singular stalk varieties can be planted closer together and bushier varieties should be given more space. Zinnias prefer full sun and well-drained soil. For longer flowering, remove the old blooms.
Zinnia Management
When planting zinnias, it’s recommended to incorporate a general-purpose fertilizer with equal parts nitrogen, phosphorus, and potassium into the soil. Following planting, monthly fertilization with a phosphorus-rich fertilizer is advisable to encourage continuous blooming. Maintaining adequate moisture is crucial for zinnias but avoid overwatering as they thrive in moderately dry conditions. To prevent fungal diseases, water only when the top 1-2 inches of soil are dry, focusing on watering the base of the plant rather than the foliage whenever possible. Powdery mildew is a common issue with zinnias, but it can be managed by applying a fungicide when necessary. However, it’s best to prevent this problem by ensuring good air circulation and avoiding wet foliage.
Photo: De’Anthony Price Diseased Zinnia
Zinnias as Cut Flowers
Zinnias, known for their vibrant charm, make delightful cut flowers that can brighten up indoor spaces for a week or longer. For optimal longevity, harvest the blooms when their centers are just beginning to unfurl fully. Trim away lower leaves and promptly place the cut ends into water-filled vases. Regularly refreshing the water helps prevent the growth of algae. When it comes to drying zinnias, double-flowered varieties are preferred as they tend to maintain their shape better than single forms. While all colors undergo slight changes during drying, cutting stems at their peak, removing leaves, and hanging them upside down in bundles away from direct sunlight facilitates the drying process effectively.
