Controlling Wasps, Yellow Jackets and Hornets

The family Vespidae in the order Hymenoptera contains the hornets, yellow jackets, Polistes and potter wasps. All of these individuals can be referred to as wasps.



The bald faced or white faced hornet, Vespula maculata, (Figure 1.) is black with wihte markings on the tip of the abdomen and white or pale yellow markings on the face and thorax. They range from on-half to three-quarters of an inch in length. The nest is usually aerial, located on the limb of a tree or under the eave of a home. Sometimes they are noticed lower to the ground in a tall shrub or thicket. The nest is started by a single fertilized queen in the spring. She initially constructs a comb containing 10 cells surrounded by several layers of paper. The paper is composed of decomposed wood, which the queen collects, masticates and then works into place to construct the nest.

The first hornets raised in the spring are workers and incapable of mating. These expand the nest and do the work in the colony for the remainder of the season; including the feeding of the larvae which become queens and drones in the fall.

At the end of the season, a nest can contain several thousand insects. The nest is seasonal. Queens will overwinter and start new nests in the spring, while other individuals in the nest will die with cold weather in autumn. The nest is not used for more than one season.

The European hornet (Figure 2.), Vespa crabro germana, was introduced into North America from Europe in the mid-1800's. It is a heavy-bodied wasp, which can range from three-quarters to approximately one inch in length. It is brown with yellow and orange markings. Adults collect various insects, which they feed to their young. The adults feed on nectar and in autumn they may actually feed on juice from ripening fruit. Sometimes these insects are seen stripping the bark off shrubs or trees. They are similar in biology to yellow jackets. Nests are constructed in hollow areas in trees or at times in hollow areas between walls in buildings. These hornets are sometimes attracted to lights at night and may be a nuisance near doors and window screens. The nests are seasonal.

There are six species of yellow jackets native to New York State. Yellow jackets (Figure 3) are shiny yellow-and-black wasps. They range in length from one-half to approximately three- quarters of an inch. Fertilized queens start nests in the spring in ground depressions or cavities or sometimes in hollow logs on the ground. Usually the only visible sign of the nest is an entering/exiting hole in the soil. The larvae are fed flies and other insects and the adults feed on nectar and other sweet liquids. Yellow jackets become a nuisance around picnic areas, garbage receptacles, etc., where sweet things, such as fruits and soda cans exist. Nests are also seasonal.

A European species of yellow jacket, Vespula germanica, was introduced into the northeastern United States about forty years ago. This species looks similar to the native species in New York. Unlike the native species, it prefers to build nests inside the walls of homes. It feeds on the same foods as the native species and its nests are seasonal also. It may be more aggressive in late summer than the native yellow jacket species.



Polistes
wasps are those which construct paper nests which resemble small open honeycombs (Figue 4). Polistes, or paper wasps as they are called, are reddish-brown to dark brown in color. Some have black, red or yellow markings on the body. They range in size from one-half to one inch in length. Paper wasps are long-legged and the abdomen is slender and attached to the thorax by a short petiole. The nests are usually no more than four inches in diameter and contain only a few larvae and adults in comparison with other wasps in the Vespidae family. Most of the nests are constructed under the eaves of homes or in attics. The nests are also seasonal.

Management of Wasps, Yellow Jackets and Hornets

Management without insecticides

Most are paper wasps that use wood pulp to build their nests. They are attracted to unfinished wood decks, lawn furniture, or awnings; and usually build their nests there. Painting or oiling these surfaces reduces their attractiveness to paper wasps. Check periodically around the outside of the house during early summer to find and remove small nests. By August and September, wasp populations will be highest. Use screens in buildings and screen ventilators to attics. Species in New York State are annual nesters. If possible, wait until frost kills insects, then remove and dispose of nests.

Management with insecticides
For nests located outside: use commercially available wasp and hornet sprays of mint oil, Baygon, cyfluthrin, permethrin, pyrethrins, resmethrin, or rotenone formulated in pressurized cans. Apply at night directly to nest opening(s), preferably when the temperature is cool. Wear protective clothing: long sleeves, trousers tucked into socks, gloves, and a beekeeper's hat or mosquito netting draped over a wide-brimmed hat and fastened to protect the face and neck from stings.

Note: for digger wasps use deltamethrin as per label directions.

If large numbers enter a building, a commercial wasp and hornet spray or a spray for indoor flying insects may be used. Caution: insects trapped indoors may be irritated and can sting.


Pesticide recommendations obtained from: Part I Guide to Pest Management around the Home – Cultural Methods, Cornell Misc. Bulletin S74I and Part II Guide to Pest Management around the Home – 2003-2004 Pesticide Guidelines, Cornell Misc. Bulletin S74II.

The Pesticide Management Education Program (PMEP), in cooperation with the New York State Department of Environmental Conservation (NYSDEC), maintains a web site with a searchable database for pesticide products currently registered in New York State. Homeowners who have Internet access can locate currently registered products at http://pmep.cce.cornell.edu/pims/current. Several different queries are available that will produce a summary for the product(s) that the system locates. If the system fails to locate the product in question, then that product is not currently registered in New York State. The database also provides a summary of important information related to every product currently registered. Two data fields "Status" and "Expiration Date" are provided in each summary. Products with a status of "Registered - Discontinued" are currently registered but will probably be discontinued for use, sale, and distribution in New York State after the date noted in the "Expiration Date" field.

This publication contains pesticide recommendations. Changes in pesticide regulations occur constantly and human errors are still possible. Some materials mentioned may no longer be available, and some uses may no longer be legal. All pesticides distributed, sold or applied in New York State must be registered with the New York State Department Of Environmental Conservation (DEC). Questions concerning the legality and/or registration status for pesticide use in New York State should be directed to the appropriate Cornell Cooperative Extension specialist or your regional DEC office. Read the label before applying any pesticide.

For more information contact: Tom Kowalsick, Extension Educator - Horticulture, CCE - Suffolk County

Horticulture Leaflets Online

10/03