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.
Paper wasps can hide among vegetation and surprise gardeners. Credit: UF/IFAS
As summer comes to a close, 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 over areas where they are not wanted. As you begin to hack these 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.
Wasps and yellow jackets are closely related in the insect family Vespidae. 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 a female from another nest, they die. Once the fertilized females emerge in late fall, they 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, yellowjackets, and hornets can sting multiple times. Yellowjackets and hornets even emit an alarm pheromone that causes other members of the nest to aggressively defend the colony.
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.
There are three species of yellowjacket in Florida, including the eastern yellowjacket (Vespula maculifrons), southern yellowjacket (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. Yellowjackets build extensive colonies underground, though can also build colonies in hay, palm fronds, and other loose debris aboveground. These underground colonies usually have a single entrance but can also have multiple entrance holes. Hornets build aerial colonies. Gardeners are most likely to have run-ins with yellowjackets since hornet nests are typically up in trees and more obvious than an underground yellowjacket colony.
Southern yellowjackets create underground colonies that can hold over 2,000 yellowjackets. Credit: UF/IFAS
While these insects can be a major pain, figuratively and literally, they actually do help out us gardeners. The main food source of wasps, yellowjackets, 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, manage colonies in high-traffic areas, and prevent encounters with them. To reduce your chance of weeding right into a wasp nest, take a stick and knock around the vegetation to see if any are hiding in the brush before getting started. Be ready to run. Yellowjackets 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. Wasps can be managed by most homeowners with a broom (if the nest is small and/or relatively inactive) or aerosol insecticides specifically formulated for wasp control. Yellowjackets and hornets are trickier to deal with and should be approached very cautiously. Spraying aerosols into a yellowjacket entrance hole is dangerous and may not be very effective as some colonies can be up to a foot wide and contain over 2,000 yellowjackets. Any attempts to control wasps, yellowjackets, and hornets should be done in the evening when they are less active and with appropriate clothing that covers the skin.
Yellowjackets are pollinators and eat caterpillar pests! Credit: Whitney Crenshaw, Colorado State University, Bugwood.org
For more information on wasps, yellowjackets, hornets, and other stinging insects, see the Biting and Stinging Insects section of the UF/IFAS EDIS site (https://edis.ifas.ufl.edu/topic_biting_and_stinging_pests) or contact your local Extension Office.
As Hurricane Michael was barreling through the Panhandle region, wasp populations were at their highest of the year. Winds and flooding destroyed many of the nests of paper wasps, hornets, and yellow jackets and now wasps may be aggressive as they defend themselves or remnants of their nests. All are capable of multiple stings that are very painful. It is very likely that you will encounter stinging wasps as they scavenge for food and water, as well as seek shelter among debris and exposed trash.
Many people are stung by paper wasps after storms. They are not attracted to traps.
Here are a few pointers to help deal with stinging wasps.
Try not to swat at wasps flying around or landing on you. You may be less likely to receive a sting if you can flick them off.
Some wasps are attracted to the sap from broken or recently cut trees. Look before you reach. Wear gloves and other protective clothing when moving debris in case you disturb foraging or nesting activities.
Wasps are also attracted to sugars and water. Try your best to keep food and drink cans covered. Completely close garbage containers or bags that contain food debris.
Repellents are not effective against wasps. There are pesticides labeled to spray on smaller paper wasp nests if you find one in a spot close to people’s activity. These are usually aerosol pyrethroids or pyrethrins. Make sure you read the label carefully and use the product as directed.
Do not use non labeled products like gasoline to manage wasps. This is not only illegal but can be dangerous to yourself and the environment.
There are traps for yellowjackets that you may purchase or make. These only manage those wasps flying around, not any remaining in a ground nest.
Here is a Do It Yourself Yellowjacket trap from UF IFAS Extension.
Cut the top 1/3 off your 2 liter bottle so that you have 2 pieces.
Add a bait (fermenting fruit or beer) to the bottom of the plastic bottle.
Invert the top portion of the bottle into the base, forming a funnel.
Hang or place traps so they are about 4 to 5 feet above the ground. For safety, place them away from people.
A homemade trap to catch yellowjackets. Photo by Alison Zulyniak
I respect the fact that wasps can sting when threatened or disturbed. But I also respect the fact that they are beneficial.
Every time I’ve been stung by wasps, I either accidentally disturbed a nest that I didn’t know was there or I intentionally disturbed the nest and paid the price.
Paper wasps are common in Florida. They frequently construct and attach their paper-like nests to building eaves or the ceilings of porches. The adults seek out caterpillars, which they sting and paralyze. They then take the caterpillars back to their nest and place them in individual cells as food for the developing larvae.
I’ve witnessed the paper wasp as it stings and carries away a caterpillar from my vegetable garden. They are busy insects and are doing us gardeners a favor by reducing the population of caterpillars in our landscapes and gardens.
There are other beneficial wasps in Florida. Mud daubers, for example, build their mud-like nests on the sides of buildings close to human activity.
Mud dauber, Photo Credit: UF/IFAS Extension
The mud dauber is not as aggressive as the paper wasp. It rarely stings people. It stings and paralyzes spiders. The mud dauber lays an egg on each paralyzed spider and seals it inside a chamber in its earthen nest. Upon hatching, the wasp larva feeds on the body of the spider. An emergence hole is made as the young wasp leaves the mud nest.
It may not be wise to tolerate all wasp species living in close proximity to your home. Even though yellow jackets, a type of wasp, could be considered beneficial, they are too aggressive and too likely to repeatedly sting to have as close neighbors. I also would be concerned with any type of wasp or bee nest existing in close proximity to individuals with a known allergy to insect stings.
Just because an insect has the ability to sting, it’s not all bad. Wasps can serve a beneficial purpose. But you’ll have to decide for yourself how close to you they can build their nests. The front porch may be too close.
Posted as part of the “Best Of” series, from August, 2014
