Hornets in Turf
The term "hornet" is often used to refer to many of the wasps that build large papery nests. The most notable paper wasp is the baldfaced hornet, Dolichovespula maculata, and several species of yellowjackets (Vespula sp.), which are really wasps. In actuality the only true hornet found in the United States is the European hornet, Vespa crabro L.
Baldfaced hornets may be best described as large, black and white, heavy-bodied wasps about 3⁄4 inch long. They typically build exposed, mottled grey nests in trees or shrubs. Occasionally, the wasps will build nests under roof overhangs, in attics, crawlspaces and wall voids, or under decks or porches. The nests are constructed of a paper-like martial formed from chewed wood. The nests are often described as "football shaped," but they may exceed a basketball in diameter.
Yellow jackets are house fly-sized wasps with distinct yellow and black markings and a few hairs. They construct a similar type of paper nest; however, it will be tan in color, much smaller in size compared to the hornet nest, and is usually found in an underground cavity. Common locations for nests are in lawns, particularly in sandy exposed areas, as well as at the base of trees or shrubs. Occasionally, yellow jackets will nest in attics or walls voids of houses or storage buildings.
The first decision to make is whether control is actually necessary. Two points to remember:
- In spite of their reputations, hornets and yellow jackets are actually beneficial because they prey on many insects that we consider to be pests. They also serve as food for bears, skunks, birds, and other insects.
- Unlike honey bees, hornet and yellow jacket colonies die out each year.
If a hornet nest is built high in a tree, you may choose to simply wait until the colony dies out in late fall or early winter. The nest will slowly deteriorate from weather or from attack by hungry birds.
If a nest is located where people may be stung or if you (or others) are hypersensitive to bee / wasp stings, then colony destruction may be appropriate. Here are some points to consider as you decide how to approach the problem:
- Control is best achieved by applying a pesticide directly into the nest opening. This can be done at anytime of the day, but near dusk, most of the wasps are more likely to be inside the nest. You can use any of the aerosol "Wasp & Hornet" sprays that propel insecticide in a stream about 10-12 feet. Direct the spray into the nest opening and then move away from the area in case any of the wasps emerge from the nest. You may need to be repeat the treatment on the following evening.
- Long sleeved shirt and long pants may be worn when spraying to make the applicator feel more at ease.
- Do not hold a lit flashlight or stand near car headlights or other lights. Emerging wasps may be attracted in that direction and sting anyone nearby.
- Do not pour gasoline or petroleum down a nest hole. This is extremely hazardous and environmentally unsound.
If the nest is in a wall void or other inaccessible area in your home, you may consider hiring a pest control company to do the work for you. If the nest is in a wall, it may be desirable to remove it if convenient after spraying to avoid attracting carpet beetles that can invade the home and attack garments made wool, silk or fur. Yellow jacket traps (commercial or otherwise) have not shown to be of any value in reducing a yellow jacket problem. In trash disposal or recycling areas, closed containers and the use of PDB (paradichlorobenzene) blocks may help repel some insects.
- Common name: yellowjackets and hornets, scientific name: Vespula and Dolichovespula spp. (Insecta: Hymenoptera: Vespidae).Grissell , E. E. and T. R. Fasulo. 2013 (revised). Featured Creatures, Entomology & Nematology. FDACS/DPI, EDIS, UF|IFAS. Publication Number: EENY-81.
- Yellowjackets of America North of Mexico. Akre, R. D., et al. 1980. U.S. Department of Agriculture, Agriculture Handbook No. 552, 102 pp.
- 2018 Pest Control for Professional Turfgrass Managers. Bowman, D. et al. 2017. NC State Extension Publication AG-408. 81 pp.
- Extension Plant Pathology Publications and Factsheets
- Horticultural Science Publications
- North Carolina Agricultural Chemicals Manual
For assistance with a specific problem, contact your local Cooperative Extension Center