As we enter September, many gardeners are getting their landscapes back in shape after the long, hot summer months. There are likely some large weeds and/or vines that have taken up areas where they are not wanted. As you begin to hack these weeds back, it is wise to be on the lookout for wasps and yellow jackets. These stinging insects pack a punch and are particularly active this time of year.
All in the Family
Wasps, yellow jackets, and hornets are closely related in the insect family Vespidae, from the Latin word for wasp – vespa. These are social insects, similar to ants and bees, that have a division of labor with a queen and workers (both female) carrying out specific tasks for the colony. Males arise from unfertilized eggs and are only needed for reproductive purposes. Once they mate with the next generation of queens, they die. The fertilized females emerge in late fall and will overwinter under the bark of a log, or other safe habitat, until spring, when they start a new colony. Unlike bees, who die after a single sting, wasps, yellow jackets, and hornets can sting multiple times. Yellow jackets and hornets even emit an alarm pheromone that causes other members of the nest to aggressively defend the colony.
Wasps
While there are many different species of wasp in Florida, including the paper, red, mason, potter, and mud dauber wasps, the paper and red wasps (Polistes spp.) are the ones that tend to be most aggressive when provoked and cause a harmful sting. Their nests are often found under house eaves or hidden in amongst shrubbery. These nests hidden in vegetation are the ones that gardeners typically run into when trimming or weeding.
Yellow Jackets and Hornets
There are three species of yellow jacket in Florida, including the eastern yellow jacket (Vespula maculifrons), southern yellow jacket (Vespula squamosa), and baldfaced hornet (Dolichovespula maculata). All three can be aggressive and sting humans, especially if they feel threatened, such as when pruning or working over or near a colony. Yellow jackets commonly build extensive colonies underground, though they can also build colonies in hay, palm fronds, and other loose debris aboveground. These underground colonies can have one or multiple entrances. Hornets, really just a yellow jacket that builds aerial colonies, are also present in Florida. However, gardeners are less likely to to have run-ins with hornets since their spectacular aerial nests are more obvious than an underground yellow jacket colony.
Benefits and Careful Control
While these insects can be a major pain, figuratively and literally, they actually do help gardeners. The main food source of wasps, yellow jackets, and hornets are caterpillars and beetle larvae, which are often garden pests. They are also native pollinators. Therefore, it’s best that we accept some in the landscape, prevent encounters with them, and focus on managing colonies in high-traffic areas. To reduce your chance of weeding right into a wasp nest, take a moment to look around and use a stick to poke the vegetation before getting started. Be ready to run! Yellow jackets are harder to avoid as they are stealthy in their underground bunkers.
When it comes time to remove these insects from near a structure or heavily trafficked area, you may want to consider hiring a professional pest control company. While wasps can be managed easily with a broom handle (if the nest is small and/or relatively inactive) or aerosol insecticides specifically formulated for wasp control, yellow jackets and hornets are trickier to deal with and should be approached very cautiously. There are specific foaming aerosol sprays for underground yellow jacket colonies that are effective, but this can be dangerous task since a colony can contain over 2,000 yellow jackets. Any attempts to control wasps, yellow jackets, or hornets should be done in the evening when they are less active and with protective clothing that covers the skin.
For more information on these insects, the UF/IFAS AskIFAS website has publications on wasps, yellow jackets and hornets, and other stinging or venomous insects. You can also contact your local Extension Office.
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