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sealing all food containers, and locate garbage re- Mud daubers are solitary wasps who construct mud ceptacles away from eating areas. Reduce avail- nests and provision them with paralyzed spiders. Our able water for nest building and drinking, by repair- common two species are medium sized, and ing defective spigots and promote drainage in ar- shiny blue/green or black and yellow. eas where water can accumulate. These insects are non-aggressive and stinging incidents are extremely rare. Depletion Trapping These types of devices will not produce consistent If you discover a yellowjacket nest or reliable results. Some commercially available traps utilize a chemical lure to attract the insect to AVOID THE AREA! the trap. These chemicals attract not all yellow- Þ Mark the site and keep children or pets away from jacket species. Once the insect has entered the the nest. trap, they have difficulty in finding their way out and Þ Wear light colored clothing when nearby. they usually die inside from exposure. Homemade Þ Do not disturb the nest area or operate heavy traps can be constructed by suspending meat over equipment. open containers of soapy water. If the insect cuts Þ Get professional help to exterminate the nest. GENERAL INFORMATION off too large a piece of meat, it will fall into the wa- ter and drown. Traps should be placed away from If you are attacked by yellowjackets people or food. Yellowjackets are social insects that live in a Note: Inexperienced people should not attempt to LEAVE THE AREA QUICKLY! colony. Most species are medium sized in- destroy a yellowjacket nest. This should be left to a Þ Most of the angry yellow jackets will remain behind sects with black & yellow or black & white licensed pest control company or vector control to protect the nest. markings. Yellowjackets normally nest in agency. These trained professionals have the Þ Use loose clothing to cover your face, eyes and abandoned rodent burrows in the ground, proper equipment to control the nest safely. mouth. but some species builds aerial nests in trees, and others nest in buildings. First aid for yellowjacket stings OTHER STINGING INSECTS When a yellowjacket nest is disturbed, de- fending workers may attack in numbers and There are a large number of solitary wasps and Þ Wash the affected area with soap and water. stinging ants in the environment. Most of these in- inflict enough stings to create a life threaten- Þ Apply topical anesthetic if available. sects carry out their lives without being noticed by ing situation for individuals hypersensitive to Þ Know the symptoms, which indicate an allergic re- humans. Some of the most commonly encountered the venom. action. examples are: Þ Consult a physician if you have a history of sensi- In late summer, the Yellowjacket population tivity and Þ Obtain a specialized first aid kit for insect stings. is at its highest level, and foraging workers Paper or umbrella wasps are social insects related may resort to scavenging to provide enough to yellowjackets. They build circular exposed nests food for the colony. In addition expanding of wood pulp and are frequently seen in the eaves of houses and in trees. Most For more information call: nests in structures may cause damage to species are yellow and black, but some walls and insulation. Most yellowjacket spe- have a reddish brown color. These Alameda County Vector Control cies are beneficial to man because they prey insects are beneficial and seldom sting humans. Services District on insects and other yellow jacket species. They can sting when mishandled or overtly pro- 1131 Harbor Bay Parkway, STE 166 voked. Alameda, CA 94502 (510) 567-6800 This species is more inclined to build its nest in YELLOWJACKET NESTS YELLOWJACKET CASTS structures than V. pensylvanica and V. vulgaris, and colonies surviving more than one season has been Nests contain three types of yellowjacket casts: documented. In some regions it will construct its’ Yellow jackets use wood fibers from a variety of nest above ground in thick bushes, such as junipers plants to produce a paper like material for nest and cypresses. Its reputation as a scavenging spe- cies on the East Coast is well documented. It is rela- construction. The nest consists of a series of tively rare in the Bay Area due to competition from suspended combs that contain cells where the Queens: establishes nest, lay other scavenging species. young are reared. The combs are enclosed in- eggs side one or more layers of paper envelope. The Aerial Yellowjacket (Dolichovespula arenaria) This surface of the envelope is textured with a gradi- species is somewhat rare in the Bay Area, but is ent of color from gray to yellowish brown. Males: they have a reproductive quite common throughout the coastal and montane role portions of California. Nests are constructed above ground in trees and on buildings. The rarity of this LIFE CYCLE (Queen and Male) species in urban areas may be related to the visibi l- Workers: forage for food, protect ity of the nests and human apprehension about the nest, construct nest, feed stinging insects in general. Even though typical Yellowjackets have four life stages: nests include 100 to 700 workers, stinging incidents young and the queen. are rare because it is not known to scavenge. The egg > larva > pupa > adult preferred food of this species consists of nectar, COMMON CALIFORNIA small insects and caterpillars. As a result it is con- YELLOWJACKETS sidered a beneficial insect, and control should not be necessary, unless the nest may become an attrac- Western Yellowjacket (Vespula pensylvanica): This tive nuisance to children. species is a major pest in California because it can de- Other yellowjacket species: Occasional species velop large colonies, up to 5000 workers, which have which may be encountered in the Bay Area include an affinity to scavenge. In addition it tends to nest in the Bald Faced Hornet (Dolichovespula maculata), the open near recreational areas, and is a common (Eastern Yellowjacket Life Stages) the Forest Yellowjacket (Vespula acadica), and the visitor to picnic areas and garbage receptacles. It is a California Yellowjacket (Vespula sulphurea). The ground nester, usually in abandoned rodent burrows. first two are typically found in deeply forested terrain Its workers have been known to forage up to 1800 feet and rarely interact with humans. The later is typically from the nest, but the normal foraging range is about found in the Upper Sonoran Zones near creeks or a. 1100 feet. The number of workers in the nest will reach reservoirs that are close to transitions from chapar- its highest population level in late summer, then the ral to oak woodland habitats. b. numbers begin to gradually decline until the onset of significant rainfall. YELLOWJACKET CONTROL Common Yellowjacket (Vespula vulgaris): This spe- cies is found in the Holartic regions of Europe and As the summer season progresses scavenging yel- North America. It is also a ground nester, and is also lowjackets will increase in numbers, and become c. d. called the woodland yellowjacket, because it is com- nuisances in parks, campgrounds and recreational monly found in forested areas. It is less common at areas. Elimination of the pests can only be effected back yard barbecues than V. pensylvanica, but can be by total destruction of the nest. Yellow jacket num- a major pest in campgrounds and picnic areas. bers can be reduced by: Yellowjacket life-cycle (Vespula pensylvanica): a. Mating; b. fertilized queen in diapause during winter German Yellowjacket (Vespula germanica): This spe- Sanitation months; c. queen nest beneath soil surface; d. nest at cies was introduced into the United States approxi- peak of colony development. mately fifty years ago on the east coast. Since intro- This is the most effective method of avoiding these duction it has expanded its range to the pacific coast pests. Reduce available food by covering or tightly states. .

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