EB0643 Western Yellowjacket
Paravespula pensylvanica
Yellowjackets
and Paper Wasps
Paper Wasp
Polistes
Yellowjackets and Paper Wasps
Peter J. Landolt and Arthur L. Antonelli
Paper wasp queen, Polistes aurifer (= fuscatus aurifer ), tending
aerial nest.
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Yellowjackets and paper wasps are beneficial incts. They feed their young numerous incts that ordinarily damage shade trees and crops. They also kill countless houflies and blow flies.
A few species of yellowjackets,however, such as Vespula pensyl-vanica (western yellowjacket),V. germanica (German wasp),and V. vulgaris (common yellow-jacket), scavenge for meat and sweets and can become pests,especially at picnics and camp-grounds. Even though they may at times become pests, yellow-jackets and paper wasps are highly beneficial. Do not control them unless their stings prent a hazard.
Life Cycle
In the Pacific Northwest, yellow-jackets and paper wasps have annual colonies. The only colony members to overwinter are inm-inated queens, which spend the winter in protected locations, such
as under bark, in stumps and logs, and within stacks of fire-wood. The native Polistes aurifer (golden paper wasp) frequently overwinters in attics of homes.The queens emerge during the first warm days of spring (as early as March and April), lect a nest site, and build a small paper nest in which they lay their eggs. When the eggs hatch,the queen feeds the young larvae for up to 3 weeks. Larvae then pupate, to emerge as smaller infertile females called workers.Once the first five to ven work-ers appear, they begin rearing and feeding the brood. The queen rarely is en again outside the nest. The colony then expands rapidly, and depending on the species, may consist of as many as 5,000 workers and 15,000cells in the nest for some yellow-jacket species.
Colonies attain maximum size in August and September. Worker yellowjackets, then at their peak,
become pestiferous. About this time, new males and queens are produced from reproductive cells.The emerge and mate. The males soon die, and the inmi-nated queens ek sheltered loca-tions in which to overwinter. The abandoned nests rapidly decom-po and disintegrate during the winter. They are not ud again.In spring, the cycle starts over.The German wasp has become widespread in Washington.The cycle of this yellowjacket is slightly later, with peak colony size occurring in October and early November. This species has a propensity for nesting in struc-tures and has become a wide-spread urban pest. Recently, the European paper wasp (Polistes dominulus )
also has become wide-spread and abundant through-out Washington. It readily nests on and within human-made structures and is particularly populous in urban and subur-ban areas. The tendency of the German and European species to found nests in association with people contributes to their pest status.
Identification
A typical yellowjacket worker,Vespula pensylvanica , is shown on the cover. Yellowjacket work-ers are about 1/2 inch long,and appear short and stocky.All yellowjackets are yellow and black or white and black. Paper wasps are up to 3/4 inch long,and are more slender (e cover).Paper wasps may be distin-guished from yellowjackets by their more slender body shape
通用作文
结婚蛋糕
LIFE CYCLE OF YELLOWJACKET. Diagram of underground nest ctions, above left. Queen begins building a new nest in spring, upper right. Nest expands rapidly in summer as the number of workers increas, middle right. In late summer-early fall, worker populations and the colony are at their peak, lower right. The colony begins to decline, and the derted nest disintegrates rapidly in winter. Queen, lower left, in diapau position, overwinters under loo tree bark, roof shakes, or other protected location. Worker populations reach their peak in late summer, center (not drawn to scale, workers are 1/3 to 1/2 the size of queens). New males and queens mate, lower right; males die, and inminated queens ek winter shelter. The cycle begins again in spring. Maximum size is attained in August or September.
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Nest of the aerial yellowjacket,
Dolichovespula arenaria.
Expod subterranean nest of
the western yellowjacket.
Guard workers of the western
写西湖的诗句
yellowjacket on mud turret
around entrance hole to
subterranean nest. 4
Western yellowjacket workers often scavenge for meat or sweets at picnics. Workers will feed pieces of meat to developing larvae
in the nest.
and longer legs. Although the golden paper wasp is easily dis-tinguished from yellowjackets by its yellow and dark brown coloration, the newly introduced European paper wasp is quite similar in color pattern to yellow-jackets. Identification is impor-tant, becau paper wasps are valuable as biological control agents of garden pests.
Types of Nests
眉骨高的男人比较的意思Yellowjacket nests are built男子哪里好
entirely of wood fibers and con-sist of multiple stacked combs completely enclod by a paper envelope, except for a small entrance at the bottom of the nest. Nests of most species are placed underground in rodent burrows or other soil cavities.The German wasp, however,often makes its nest inside walls of hous. The aerial yellow-jacket (Dolichovespula arenaria )and bald-faced hornet (Doli-chovespula maculata ) usually make their nests in trees or on the outside eaves of buildings.Paper wasps also build nests of wood fiber, but their nests consist of a single comb not enclod by an envelope. An average nest of the golden paper wasp, the only paper wasp native to Washing-ton, consists of about 200 cells,while the largest nest is probably less than 400 cells. Golden paper wasp nests are most noticeable under eaves of buildings, but they are also constructed in logs,under rocks, within shrubs and grass clumps, and inside pipe.Nests of the European paper wasp are often less than 100 cells in size but may posss 400 cells and more. This wasp appears to be quite flexible in lecting nest sites, including under roof shakes, within meter boxes, bird hous, outside grills, and mail
boxes, under eaves, chairs, and benches, and within shrubbery.
Control
Yellowjackets and paper wasps can be pests when they build a nest on or near your hou.Yellowjackets may also be attracted in large numbers to food at picnics and to garbage cans. Various controls follow.Select tho most suitable for your needs. Remember, yellow-jackets and paper wasps are beneficial incts—control them only if only absolutely necessary.Yellowjackets and paper wasps do not reu their nests the fol-lowing year, although paper wasps may construct a new nest adjacent to an old one. Knowing this may help you decide if you want to risk being stung during a control operation, especially if the nest is in a rarely ud area of the yard. If you choo to leave the wasps alone, the nest will usually disintegrate over the winter months. If the nest is on the eaves of the hou or in an
attic, it is advisable to remove it after the wasps are gone, becau the nest may rve as a home of carpet beetles or other inct pests.
Nests
Aerial nests. Aerial nests are easily controlled using some of the newer aerosol products that propel the incticide up to 20feet. Effective materials to u are the synthetic pyrethroids,which have a quick knockdown effect. Apply in the evening after most yellowjackets or paper
书画展活动方案wasps have returned to the nest.Direct the initial spray stream into the hole or face of the nest,then thoroughly wet the entire nest. Do not attempt to remove the nest until you are certain that all wasps are dead. This may take a day or two, since some foragers do not return to the
颤栗拼音nest every night. However, when they do return, the incticide residue should kill them rapidly.Underground nests. U a registered hornet and wasp spray. Direct the material into
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