Garden column for the Salisbury Post

Darrell Blackwelder

September 23, 2004

     Yellow jackets seem to be more active now, pestering picnickers or those trying to enjoy outdoor activities.  These insects can make the most casual activity a nightmare by constantly buzzing food or drink.  The small insects' reputation for delivering a powerful sting adds concern to the aggravation as their sting may be lethal to those with allergies.

    Yellow jacket workers are most active during the mid-day foraging food and cellulose for the construction of the nest.  Yellow jackets are somewhat beneficial since they feed on small adult insects and larvae for their source of protein. The insects’ source of carbohydrates is nectar and honeydew secreted by aphids or scales. 

    Closely related to wasps and hornets, these creatures choose to make their home in underground paper nests. Nests can also be found in flower pots and other containers resting on the ground or the side of a building. What seems to be of interest is the number of complaints about yellow jackets nesting in walls this season. Fortunately, the nests are abandoned each year in the fall.

     Yellow jackets over winter as mature, fertilized queens. When the weather warms in the spring, the queen selects a nesting site and builds a single comb.  The queens forages for food and feeds the first larvae while newly hatched workers in large the nest and tend the young.  Underground nests may develop several layers of comb during the summer. 

     Future queens and males are produced for next year’s colony in late summer.  After mating, the males die and the females seek a suitable site to over winter.

     The entrance to the underground nest is a single hole or cavity about the size of a quarter. Workers, tirelessly migrate in and out of the single entrance during the day. 

      The best time to treat the underground nest is late evening or at night when the yellow jackets are quite and all in the nest. Early in the morning when it is still cool is also an excellent time to eliminate nests.  Wasp and hornet sprays that spray a straight stream of insecticides work best in destroying the insects' nest.  Point the steady stream to the entrance hole and empty an entire canister or two of the insecticide into the entrance hole.

     Cover the hole immediately to encapsulate the vapor, insuring a complete kill. Yellow jackets should be dead within 24 hours after an application of the aerosol insecticide.

     Pouring a small amount of gasoline down the entrance hole is not recommended since it presents a fire hazard and may also damage plant material near the nest.  Over-the-counter aerosol pesticides (wasp and hornet killers) from retail outlets and garden centers are quite effective. 

     Always read the label before applying any pesticide.  Contact the Cooperative Extension Service should you have any questions about the usage of any pesticide materials.