L-1828
Wasps&Yellowjackets
alloggio in albergo economico StavangerBerlin hotelshotels in PiraeusGarland McIlveen,Jr. and Philip J. HammanExtension Entomologists
The Texas A&MUniversity System
 
Most wasp species are considered beneficial insects since they kill numerousflies, caterpillars, beetle larvae and other insects which are pests inurban and agricultural ecosystems. However, because of their propensityto nest near urban structures and their stinging ability, most people considerwasps to be a nuisance.
  There are some4,000 species of stinging wasps in the United States alone, and about 15,000in the world. Most are solitary and inoffensive insects that use theirsting to paralyze their insect and other small prey. Some wasps are socialinsects. That is, they live together in communities where they share foodand cooperate in raising young. Other wasps are solitary and do not collaboratein this way. Each female makes a nest of some sort for her own young. Shemay nest close to others of her species, but except in rare cases she worksalone.
   In this publication we will discuss only those wasp species that are problemsaround structures and other places people are likely to frequent.

Wasp Stings
   It is reported that at least 200 persons die each year in the United Statesas a result of anaphylactic shock following the stings of wasps and bees.This figure does not include deaths reported as heart attacks and heatstrokes which actually may have resulted from stings. Nor does it includedeaths in automobile accidents which may have been caused by wasps in cars.
   Social wasps vigorously defend their nests when disturbed. Their powerfulvenom, a mixture of enzymes and protein, is injected by a needle-like projectionfrom the tail end of the body, usually called simply the stinger. Thesting may be scarcely perceptible or may cause almost unbearably severepain. While the pain is usually localized at the site of the puncture,there may be various systemic effects, and some people develop allergiesto the venom. Nearly 80 percent of all venom related deaths occur within1 hour after a sting.
   Yet, on the whole, the danger of wasps has been exaggerated. The vast majority,perhaps 90 percent of the known species, are solitary wasps that causefew problems. Their venom is quite different from that of social wasps,and seldom causes more than momentary pain. Also, solitary wasps are notaggressive and usually do not attempt to defend their nests.
   Except in a few tropical social wasps, the stinger does not remain in thewound with the poison sac attached, as is the case with honey bee stings.Therefore, a single wasp can sting its victim repeatedly. Since the stingeris a modified ovipositor or egg laying tube, only the females are ableto sting.
Social Wasps
PaperWasps
five star hotel in Amsterdam   Paper wasps are the wasps most noticed around homes and other buildings.These are slender, narrow-waisted wasps with long legs. There are threecastes--the queen and males, which are produced only in late summer orfall, and infertile female workers. The queen is not discernibly largerthan the work-ers, as are yellowjacket queens. Paper wasps are 3/4 to 1inch long and reddish-orange to dark brown or black in color. They oftenhave yellow body markings.
   These wasps build nests from wood fiber to form a single comb of hexagonalcells which are oriented downward. These nests are umbrella-shaped andsuspended by a single filament. Unlike yellowjacket nests, they are neverenclosed in an envelope. These nests are most noticeable on the eaves ofhouses, but also can be found in attics, garages, storage sheds, barns,shrubbery, trees, grass clumps, logs, under patios and inside pipes usedas clothes line poles. The typical mature paper wasp nest contains 20 to30 adults and rarely more than 200 cells.
  Colony founding. Colonies are founded in the spring by inseminated,overwintered females. These foundresses are the late summer daughters ofthe previous years queens. They have mated in autumn, then hibernatedin groups or singly, secreting themselves in cracks and crevices of oldlogs, attics and barns. Males never survive the winter, but their spermdo in the sperm sac of the overwintering female. A queen thus has a constantsupply of sperm without repeated mating.
   In late summer, well before the onset of cold weather, the queen stopslaying eggs and adds no new cells to the nest. But eggs, larvae and pupaecontinue to develop and the adult population continues to grow as moreoffspring emerge. When egg laying stops the colony begins to show signsof decline and eventually dies off. The following spring, the overwintered,mated queens emerge from hibernation and construct new nests. Paper waspsdo not re-use nests from a previous year.
  Control. Aerial nests of paper wasps can be easily controlled withaerosol pyrethroid products containing resmethrin, tetramethrin or permethrin.Products containing propoxur or chlorpyrifos may be used also. Some aerosolswill propel the insecticides 10 to 40 feet or more. For best results, treatin the late evening when most wasps have returned to the nest. When spraying,stand well away from the colony and soak the nest thoroughly. Do not removethe nest until all the wasps are dead, which may require up to 2 days.Then the nest should be removed and discarded.

Yellowjackets
   Yellowjackets are easily recognized but are often confused with paper wasps.Baldfaced hornets are also yellowjackets, but because people often viewthem differently, they will be discussed separately.
   Worker yellowjackets are strikingly marked with black and yellow bands.The queens are one and one-half to three times larger than the workersand are marked with black and orange bands.
   Yellowjackets construct their nests of a paper-like material consistingof wood fiber. Unlike paper wasp nests, they are completely enclosed inan envelope except for the entrance hole. In Texas, nest size may varyfrom a few inches to 6 feet or larger, and nests may contain up to 45 levelsof combs and 20,000 adult workers.
   Yellowjackets are primarily ground nesters, but also construct aerial nests.Subterranean nests may be found in gardens, flower beds, pastures, roadsideembankments and elsewhere. Aerial nests are typically constructed in trees,under eaves, in wall voids of buildings, in open garages and storage sheds,on porches, in abandoned furniture and in other places that provide protectionand are close to food and water. Because of their scavenging behavior,yellowjackets are a menace around parks, camps and suburban sites wherepeople leave open food and discard garbage.
   Yellowjackets forage to feed their larvae meat, especially insects andspiders. They also gather nectar, honeydew and other carbohydrates, butthey do not store honey as do bees.
  Colony founding. Queens over-winter under loose bark, in cracksand crevices and occasionally in attics or similar sheltered locations.They emerge during the early spring and build small paper nests in whichthey lay eggs. When the eggs hatch, the queen feeds the young larvae forabout 18 to 20 days. After the first brood of workers reaches adulthood,the nest may rapidly expand up to a foot long or larger within a few daysor weeks. Maximum colony size is attained in August or September. Thisis followed by the emergence of males and the next years queens in Octoberand November. These mate and the males die. The inseminated queens seeksheltered locations in which to overwinter. The nest may be abandoned.If so, it rapidly decomposes and disintegrates during the winter. If thenest is not abandoned and the existing queen(s) and her workers continueto maintain it through the following year, it is termed a perennial colony.Annual nests are not re-used.
  Control. If it becomes necessary to destroy a yellowjacket nest,wear protective clothing such as a bee suit or hire a professional pestcontrol operator. A single sting from an alarmed yellowjacket can exciteother yellowjackets to attack, resulting in multiple stings. The best timefor control is after dark when foraging activity has ceased and most workersare in their nest. Use a red light to locate the nest en-trance, sincered light cannot be seen by wasps. Underground colonies are easily killedby pouring an insecticide product containing propoxur into the entrancehole or dusting it with carbaryl 5 percent dust. Workers that return tothe nest later are killed by the insecticide. Aerosol insecticides containingresmethrin, tetramethrin, allethrin, propoxur or chlorpyrifos are convenientand effective products for controlling subterranean and aerial colonies.To treat aerial nests, spray directly into and around the entrance hole(s).Aerial nests built in wall voids can be sprayed with propoxur or chlorpyrifos.Two or more applications at 7- to 10-day intervals may be required to obtaincomplete control. Where the nest is not easily accessible and rapid controlis desired, as in wall voids, storage sheds, stored furniture or underground,treat with total release aerosols containing either permeth- rin, tetramethrin,cyfluthrin or resmethrin. To be effective, the nest area should be coveredand completely sealed off (preferably with clear plastic sheeting) beforetreating. Use duct tape on solid surfaces to seal around the edges of theplastic and other openings where the pesticide vapor could escape. On theground, the plastic sheeting can be tacked with pieces of U-shaped, 10-inchcoat hanger or similar wire, or the edges can be sealed with sand. Be carefulnot to disturb the nest. Insert the required number of total release aerosolcontainers (see the label) under the plastic and leave at least 12 inchesclearance between the plastic and aerosol container. Wait 15 to 20 minutesbefore uncovering the nest, or until all the yellowjackets are dead. Removeand discard the nest.

Hornets
ERROR MSG   The baldfaced hornet is the only hornet reported in Texas. It is actuallya member of the yellowjacket family. Baldfaced hornets are large (up to3/4 inch long) and black with white markings, particularly on the frontof the head. They construct an inverted, pear-shaped, enclosed paper cartonnest which can be up to 3 feet long. The grayish to brownish nest has twoto four horizontally arranged combs and an entrance hole at the bottom.Nests usually hang in trees, but may be attached to the sides of buildings.A mature colony may contain from 200 to 400 adults. Their sting can beintensely painful.
   When attempting to control baldfaced hornets, always wear protective clothingsuch as a bee suit or hire a professional pest control operator becausethe hornets are likely to attack. Sprays containing propoxur, dichlorvosor chlorpyrifos should be directed into the nest opening. The entire nestshould be soaked. Insecticide products containing synergized pyre-thrinsand a rapidly volatilizing organic solvent, such as Wasp Freeze®,can be extremely useful; in addition, hornet and wasp sprays containingpyrethroids such as tetramethrin and permethrin are effective. Hornet nestshigh in trees or in other remote locations where they pose no threat tohumans should be left unharmed.
Solitary Wasps
CicadaKillers
   This large insect is 1 inches long, rusty red on the head, thorax and wingsand striped with black and yellow on the abdomen. These wasps are a nuisancein landscapes during times of the year when cicadas are present in shadetrees. Cicada killer wasps appear formidable because of their size andbehavior. Male cicada killers cannot sting, but will buzz very near humans.Females will not sting unless handled, but sometimes painfully sting peoplewho are working on lawns or step on their nests bare-footed. Female cicadakillers dig galleries in lawns, gardens or flower beds, where they layeggs and provision the young larvae with paralyzed cicadas. This nestingactivity may damage lawns or vegetable gardens. Control is rarely warrantedfor this otherwise beneficial insect. When control is necessary, sprinkleabout 1 tablespoon of carbaryl dust into the burrow and tamp the en-tranceshut with your foot.

MudDaubers
   These wasps build small, tube-like nests of mud under eaves, in atticsand under the roofs of storage buildings. As they develop in the mud tubes,the young larvae are generally fed spiders, including the poisonous brownrecluse. Adult mud daubers are 3/4 to 1 inch long and vary in color fromdull black with bright yellow markings to blackish or iridescent blue-black.They have longer, more slender waists than most other wasps. If necessary,mud daubers can be controlled by soaking the nest and its immediate vicinitywith a carbaryl, propoxur or diazinon spray. Aerosols containing synergizedpyrethrins, resmethrin, permethrin or propoxur also are available. Or,mud dauber nests can be simply removed by hand with a putty knife, as theattending female will not defend her nest. Even when insecticides are used,it is a good idea to scrape the nest away and dispose of it to preventother insects from being attracted to it.

Importanceof Sanitation
   The proper management of garbage denies scavenging yellowjacket workersa ready source of food for developing larvae. Therefore, yellow-jacketpopulations can be reduced by removing garbage frequently and keeping tightlids on all trash receptacles. To further reduce both yel-lowjacket andfly problems, attach a dichlorvos-impregnated resin strip (Vapona®or No-pest Strip® ) inside the garbage can lid.
   Poison bait formulations have been developed to control scavenging yellowjackets,but these are neither commercially available nor known to be effectiveagainst Texas species. Although a commercial trap is available, this isnot an effective control technique for the homeowner.
Insecticidelabel clearances are subject to change and changes may have occurred sincethis publication was printed. The pesticide user is always responsiblefor the effects of pesticides on his own property, as well as problemscaused by drift from his property to that of others.
ALWAYSREAD AND FOLLOW CAREFULLY THE INSTRUCTIONS ON THE PESTICIDE LABEL.
Formore information on insecticide products used to control wasps and yellowjackets,refer to B-1373, "Home and Landscape Pests," available from your countyExtension office.
Theinformation given herein is for educational purposes only. Reference tocommercial products or trade names is made with the understanding thatno discrimination is intended and no endorsement by the Cooperative ExtensionService is implied.


Educationalprograms conducted by the Texas Agricultural Extension Service serve peopleof all ages regardless of socioeconomic level, race, color, sex, religion,handicap or national origin.
Issued in furtheranceof Cooperative Extension Work in Agriculture and Home Economics, Acts ofCongress of May 8, 1914, as amended, and June 30, 1914, in cooperationwith the United States Department of Agriculture.   Texas AgriculturalExtension Service, The Texas A&M University System. 10M--8-91, NewENT

- | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |