Common Name: Wasp – Yellowjacket

Other Names: Paper Wasps, Meat Bees, Hornets

Origin: There are many species of Vespula in North America, including several species introduced from Europe.  Two of these, Vespula germanica and Vespula vulgaris, are among the serious scavenger pests in this group.

Biology: Yellowjackets are social wasps, with a Queen that initiated the colony and female workers that build the nest, care for the young, forage for food, and defend the colony.  Colonies typically begin each spring and die off each fall in cooler climates, but may survive over the winter in warmer climates.  The population of the colony easily grows to many thousands of workers by the end of the summer.  At this time, males are produced, and mating with new queens takes place, now these fertilized queens then overwinter in protected locations. Adults feed on sweet liquids such as honeydew, nectar, fruit juices, or human foods such as sodas.  They also relish a sugary material exuded by the larvae. The larvae are fed meat, and natural sources such as insect larvae or bits of flesh from dead animals.  As scavengers the workers also gather human food at outdoor eating areas.  The workers are all able to sting repeatedly, and will very aggressively defend their colony from perceived intruders.  Nests are placed either in aerial locations, including trees, shrubs, wall voids, or attics, as well as, in the ground where workers will enlarge holes they find to accommodate the growing colony.  The nest is created from cellulose gathered from tree bark, dried plant materials, or other sources, mixed with saliva, and formed as the hexagonal cells for the larvae.

Identification: Yellowjackets are very similar to the other social paper wasps called Umbrella Wasps, but differ by having no narrow waist between their thorax and abdomen. Colors are yellow and black, and specific identification of each species is done with differences in the patterns of the black patches around the eyes and head, as well as, on the abdomen.   Yellowjackets have 2 pairs of wings that are dissimilar in size and shape.  This separates them from many species of flies that mimic wasps, where there is only 1 pair of wings.

Characteristics Important in Control: Elimination of attractants such as spilled food materials or rotting fruits in gardens will help to prevent the presence of yellowjackets.  If they are nesting within a structure, the nest itself or opening the workers use for entry may be dusted with a residual insecticide.  Baiting using meat or syrups as the attraction will work very well if a product labeled for use in this manner becomes available.  Trapping will capture many of the foraging workers around human activity areas, but is unlikely to cause a large reduction of the nest population.