What to do about annual invasion of wasps


Tis the season for the annual invasion of wasps visiting garbage cans, outdoor picnics and unattended sodas and adult beverages. Nothing is more pleasant than taking a big swig of a favorite beverage and swallowing a wasp.

Often these wasps are mistaken for honeybees. The main difference between wasps and bees is that bees are hairy. Bees primarily feed on nectar of flowers or could be considered vegetarians. Bees also make honey. Wasps are considered carnivorous or meat eaters. Wasps sting their prey to subdue, and paralyze, and can sting multiple times. Honeybees can only sting once and die after stinging.

Both bees and wasps pollinate flowers; however, bees pollinate better than wasps, because pollen is transferred by the hairs on their bodies.

In Ohio, there are four wasp species all belonging in the family – Vespidae. The four types of wasps include Eastern Yellow Jacket (Vespula maculifrons), Northern Paper Wasp (Polistes fuscatus), European Paper Wasp ( Polistes dominula) and the most-feared Bald Face Hornet (Dolichovespula maculate).

This is the time of the year when wasps expand their nests at an exponential rate. The nests have been here since the beginning of the season; however, the wasps were flying below the radar owing to small nests containing few individuals. Wasps spend the winter as fertilized females (queens) in protected locations such as beneath bark, inside hollow trees. As spring temperatures warm, the queens leave their winter quarters to find suitable sites for nest construction.

After the queen finds a suitable spot for her new nest, she begins construction. She uses her powerful mandibles to grind up fibers gathered from dead wood and plant stems, which she then mixes with her own saliva to create a water-resistant paper nest. This construction technique continues to be used by the queen’s offspring throughout spring and summer.

Early wasp nests are relatively tiny structures. The single dominant queen produces subordinate queens to aid in expanding the nest. Collectively, they lay more eggs, that lead to more workers, that lead to larger nests, that lead to more eggs. By late August and early September, the nests become large enough to be noticed.

During the summer, wasps are significant beneficial predators because of their need to provide protein to their legless, helpless larvae awaiting food delivery to the nests. Due to hot, humid conditions in the summer, common house flies, cluster flies, and blow flies were also breeding, which in turn creates fly maggots. Throughout summer the wasps are feeding on the maggots. Besides the maggots, the wasps were also feeding on caterpillars, sawfly larvae and other soft-bodied insects. They use their powerful mandibles to grind up these protein-rich meat items to feed to their larvae so they will develop into new adult wasps.

So, why are the wasps visiting garbage cans, outdoor picnics, and unattended beverages?

Unfortunately, wasps have a deserving reputation for becoming a serious nuisance late in the season.

In early fall, the queen lays eggs that will develop into fertile drones (males) and eggs for a new queen. These new sexually reproductive wasps need energy from carbohydrates, so they lounge around the nest begging the workers for sweets.

To appease these freeloaders, the workers search for foods that have this much needed energy boost — such as soda and donuts. Thankfully for the over-worked workers, the nest populations of adults begin to peak in the fall with 5,000 or more workers in the colony.

As fall comes to an end, the new queens and drones leave their nest to mate, and the queens seek protected overwintering sites. The colony from which they themselves developed dies during the winter; Yellow Jacket and Paper Wasp nests only last one season.

This means that you should avoid declaring war on these stinging insects unless their nests are located where they present a serious stinging hazard. The nests and drones will eventually die out on their own.

Of course, wasp workers will happily demonstrate their stinging capabilities any time during the growing season. Understanding why they sting is important to avoiding painful confrontations.

These insects will sting for two reasons: to defend their nests (and young) and to deliver venom to quickly subdue their prey. Despite their belligerent reputations, wasps are seldom aggressive.

The Eastern Yellow Jacket is the wasp that builds colonies behind shutters, inside siding and around light fixtures and other exposed entryways in homes. They also build nests in the soil under ground. Hitting one of these underground nests with the lawnmower is as much fun as swallowing one of these.

To control these wasps, try two pesticide products. First is an aerosol wasp and hornet killer. The second is a permethrin garden dust.

In the early evening, before dark, locate the nest entrance. This is the area where the wasps are congregating. Spray the wasps first with the aerosol product. This will knock down all the guards and other outer entrance defenders.

Second, liberally dust the area with the permethrin dust. When the other wasps leave the nest the following day they will track through the dust. When they clean themselves, they will ingest a lethal amount of pesticide. Never plug the outside entrance as the wasps may then chew out a new exit hole and end up inside your home. Only after several hard freezes will it be safe to plug an entrance area.

Remember, even armed with serious insecticides, we are often woefully outclassed because these wasps have been defending their nests for tens of thousands of years.

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