Blackwelder column: What to do about yellow jackets
Yellow jackets have already returned this summer, causing problems for those working or trying to enjoy the outdoors.
Yellow jackets, as small as they are, can deliver extremely painful and often deadly stings. Unfortunately, one death occurred recently nearby in Charlotte due to a sting.
Yellow jacket stings are similar to wasp or hornet stings with the capability of delivering multiple stings. These insects can control the amount of venom injected, so stings may differ in intensity.
Some stings may itch only for a few hours while other stings may swell and be painful for days. Pain from stings of yellow jackets is due to the effect of biogenic amines that include histamines.
What is needed to counteract the pain and effect of these histamines are antihistamines. Wash the area stung with soap and water, and then apply an antihistamine preparation. There are antihistamines available (non-prescription such as Benadryl) that can be taken orally.
Yellow jackets are most active during midday, 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 insect’s source of carbohydrates is nectar and honeydew secreted by aphids, scales or other insects.
Yellow jackets seem to be agitated by excessive noise and vibrations. These creatures defend their nests to the death against lawn mowers, weed trimmers, chain saws and other types of power equipment.
Closely related to wasps and hornets, these creatures choose to make their home in underground paper nests. Nests can also be found in flowerpots and other containers resting on the ground or the side of a building. The nests are abandoned each year in the fall. The combs are found vertically in loose soil, looking like a fresh pancake.
A few yellow jackets survive the winter as mature, fertilized queens. When the weather warms in the spring, the queen selects a nesting site and builds a single comb.
Overwintering queens forage for food and feed the first larvae, while newly hatched workers enlarge the nest and tend the young, much like a colony of honeybees. Underground nests often develop into 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 overwinter.
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 an underground nest of yellow jackets is late evening or early morning when the yellow jackets are quiet in the nest.
Wasp and hornet sprays capable of delivering 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 of the insecticide into the entrance hole. Sprays that contain ether are effective and quick.
Cover the hole immediately to capture the vapor, insuring a complete kill. Yellow jackets should be dead within 24 hours after an application of the aerosol insecticide.
More detailed information about yellow jackets can be found at www.ces.ncsu.edu/depts/ent/notes/Urban/horn-yj.htm
Darrell Blackwelder is an agricultural agent in charge of horticulture with the North Carolina Cooperative Extension Service in Rowan County. Call 704-216-8970.