In early Summer, yellow jackets are considered quite beneficial by those involved in agriculture because they naturally feed on harmful flies and caterpillars, thus protecting food crops. During August-through-October, when their populations increase to as many as 4,000-to-5,000 per nest, they become a very serious pest all throughout Ohio as they invade human spaces, scavenging for food.

Yellow jackets are attracted to just about any human food that could be found at a picnic or in any kitchen-garbage bag: sweet sodas, juices, ripe fruits and vegetables, candy, ice cream, deli meats, hotdogs and hamburgers, fish, kitchen scraps, bones, etc. They are found harassing picnic areas, restaurants, bakeries, campgrounds, fairgrounds, outdoor sporting events, beaches, and just about anywhere else that humans congregate with food. Trash receptacles and dumpsters can be extremely problematic, with huge nests growing very closeby these constant sources of food.

The average worker yellow jacket is about 1/2"-to-5/8" in length, with alternating black and yellow blocks the length of their abdomens. The queens are slightly larger - about 3/4" in length. The workers are sometimes confused with honey bees when flying near their nests. Unlike honey bees, yellow jackets have smooth hairless bodies, and do not have flattened hind legs. The yellow jacket stinger is lance-like rather than barbed, so they can sting repeatedly.

Yellow jacket nests are naturally built either in trees and shrubs or in underground cavities, rodent burrows, etc. They are opportunistic around human-built structures, and will build their nests in the protection of building eaves, under raised decks or porches, in hollow walls or flooring, or even inside buildings when there is access, such as in attics with non-screened fans or vent slats, open sheds, and the like.

Adults mainly feed on fruits, nectars and tree saps. Larvae need to be fed meats and proteins. In a trophyllactic exchange, the adults masticate protein sources that they feed to the larvae, and the larvae secrete a sugar material eaten by the adults. In late autumn when the adult numbers are so high that the larvae cannot meet the adults sugar demands, the adults change their food preference from meats to decaying fruits.

"Yellow jacket season" in Ohio begins in May and lasts into November. Yellow jackets can be much more aggressive than bees, because stinging some thing or person will not kill them. If a yellow jacket is harassing you, it is important to avoid fast movements that will incite a sting. Wasp venoms have an "alarm pheremone", so it is very important to avoid stings, as one sting could incite a frenzied attack from any other yellow jackets in the area. For the same reason, one should never crush a yellow jacket, as the pheremone is released from their bodies when crushed.

Because of the risk of frenzy, if you find a yellow jacket nest near or in your home, it is extremely important that you contact a professional pest expert to remove the nest for you. If you suspect there may be a ground nest in your yard, do not run a lawn mower/tractor or weed whacker over the area until it is professionally inspected and addressed if necessary.

Paper wasps can be beneficial to agriculture, feeding on corn earworms, armyworms, tobacco hornworms, etc.; however, their stinging causes alarm for many, particularly those who are allergic to wasp venom. Any time a nest poses a threat to a home or other building, it should be addressed professionally immediately. Umbrella-shaped paper-like nests are built suspended by a short stalk, which is attached to eaves, window frames, porch ceilings, or attic rafters around human construction. In "nature" these nests are built under bark layers, in leaf litter, etc. Like other wasp species, they can be very opportunistic in choosing nest sites, and even build nests inside car fuel doors, under trunk decks, in door gaps, or even inside engine compartments. Nests are composed of horizontal layers or "tiers" of six-sided cells not enclosed by a paper-like envelope. The ends of the cells are open.

Like yellow jackets, adult paper wasps are attracted to sweet nectars and the juices of ripe fruits, so care to avoid attracting them is always important.

Because paper wasps have light and dark body markings that can appear very similar to other wasps if one isn't willing to "get up close and personal," it is the unique nest shape - the upside-down paper comb attached by one single stalk in a protected location - that is the key to identifying paper wasps. Up close, many paper wasps are reddish-brown or dark red, some species have bright bands of red and yellow. Most are about 1" in length, some as small as 1/2" in length, with larger species as large as 1.5" in length.

Compared to yellow jackets which build nest supporting thousands, paper wasp nests are actually much smaller, around 100 or so workers at most. Although they do not build mammoth nests, aggression in wasps is always an issue because they can sting more than once and wasp venom contains an "alarm pheremone" that incites any other wasps in the immediate area to frenzy, so it is important to take all necessary precautions when approaching an area with a known nest. If a nest must be removed, it is best to contact a professional.

Bald-faced hornets are black and white yellow jackets, 5/8" to 3/4" in length. Like yellow jackets and paper wasps, they are beneficial to agriculture because they feed on house flies, blow flies, harmful caterpillars, etc. Unfortunately, the threat of stings and nest location in proximity to humans should always be considered wherever they are found.

These hornets build nests that are grayish-brown, inverted-pear-shaped or football-shaped, as high as 3-feet tall, with the opening of the nest near the bottom. Each tier is covered with a paper-like layer, and cells are not open to view. The nests may be built as low as shrubs at ground level, or up to 60 feet or higher in trees. Nests may also be attached to sheds, houses, or utility poles. One nest may hold several hundred hornets.

If the nest is close to a walkway, home, or children's play area, the hornets will be a problem. Hornets are extremely protective of their nests and will aggressively attack and sting any intruder threatening or disturbing the nest. Nests are only used for one year. The hornets can become quite aggressive as the nest grows larger toward the end of the year. Each year in the fall, a hornet nest produces numerous queens that fly out to find a protected site to winter-over. The following spring, each queen finds a suitable site in a tree or shrub to begin constructing her own nest. Old nests are abandoned. Due to aggression and "alarm pheremone" in wasp venom, any time an active nest is found in an area that poses danger to humans, a professional should be contacted about removal.