Yellowjackets and Hornets

Insects: Yellowjackets and Hornets Yellowjacket Hornet Description Hornets and yellowjackets are both wasps that belong to the family Vespidae. They are social insects that live in a colony. Yellowjackets are about ½-inch in length and are yellow and black. Hornets are larger, about ¾-inch long, and are black and white or pale yellow. Both build nests of a papery material that consists of wood or foliage that is chewed up and formed by the insects. Yellowjacket nests are usually subterranean, but some build their nests in hollow logs, trees, or attics, between walls, or on eaves of houses. Hornet nests are usually situated in vegetation, from shrubs near the ground to 60 feet up in a tree. They may also be attached to rocks, power poles, houses, sheds, or other structures. Nests can be a few inches across or several feet in diameter. Colonies in eastern Washington live only one season. The queens overwinter in sheltered areas away from nests and start new colonies the following spring. Neither hornets nor yellowjackets reuse nests. However, the old nests may serve as indicators to the queens for a good nesting area. Both insects are beneficial because they prey on pest insects (also other insects, spiders and slugs, etc.). They capture the prey, pre-chew it and feed it to their larvae. Adults also eat pollen and nectar. Yellowjackets will feed on meat, fruits and other sweets, which is why they are such a problem in picnic areas. Yellowjackets are much more aggressive than hornets but both are very protective of nests and their young. Mere vibrations from foot traffic can set them off. The colony becomes more aggressive as it grows, so the majority of problems for people occur in late summer. Unless a colony is located near human activity or wasp populations are high, yellowjackets and hornets should not be regarded as pests and their presence should be tolerated. Since nests are not reused they don't necessarily need to be removed. However, if a nest is located in the attic, walls, or eaves, it is advised to remove it so that it won't serve as a home to carpet beetles or other pests. Exclusion  Remove old abandoned nests as they may provide invitation for new nests.  Patch, repair or fill holes in trees, siding, or the ground (insect or animal burrows).  Remove, repair and/or repaint old, unpainted wooden porches, buildings, fences, etc. These structures are preferred by queens because they chew crumbly old wood into paste for nests.  Be sure picnic areas are clean and garbage containers secured. The inside of lids can be treated with pyrethrins or bendiocarb.  Keep insect pests to a minimum. Direct Controls Aerial nests can be treated with aerosol sprays that propel insecticide up to 20 feet (examples are Advanced Garden Power Force Multi-Insect Killer R-T-S and Bonide Total Pest Control Concentrate). Read and follow label directions.). Spray from as far away as possible. Apply sprays in the evening or very early morning when most wasps are in the nest and less active. Spray entrance hole and then thoroughly wet the entire nest. Do this three consecutive days without approaching or touching nest. By the third or fourth day all wasps should be dead and the nest can be removed. Underground nests: These nests should be treated at night or early morning when most yellowjackets are less active. Apply aerosols listed under aerial nests above. Apply directly into the entrance hole and repeat for three consecutive days. Carbaryl (Sevin) dust can be poured into the entrance hole, but this is risky because you have to be very close to yellowjackets. Leave entrance holes unplugged. Returning foragers will be killed by pesticide residue. Traps for Yellowjackets 1. Hang fish or meat just over a bucket of water with detergent or other wetting agent added. The yellowjackets will drop into water when they take some meat and the wetting agent will prevent their escape. 2. Commercial yellowjacket traps are baited daily with fresh meat or synthetic attractant (Oak Farm, Rescue Yellowjacket Trap). These work quite well if enough are used (4 per average-sized yard). Safety Precautions  When spraying or removing nests, wear long sleeves and long pants and cover your head, neck and hands. Wear glasses or goggles if possible.  If you are allergic, do not risk treating wasps yourself. Have someone else do it.  Keep children and others from throwing rocks, etc. at nests.  You are a less attractive target for stings if you do not wear perfume, hair sprays, or bright colored clothing, especially yellow, blue, orange or red.