By Mike Kobus
Fall in the foothills of El Dorado County can be the best time of year. Time to take a leisurely hike in the forest (watch your step) and enjoy a late afternoon barbecue on the back deck (what keeps buzzing around my hamburger?)
What are they?
They are yellow jackets — one of the most aggressively annoying pests in El Dorado County. Yellow jackets are a type of vespid wasp. They are commonly mistaken for bees, but can be differentiated from the latter by their lack of hair. Yellow jackets also tend to have brighter yellow and black markings on the tail. These bright markings are a means of letting predators and potential foes know they are dangerous. This is called warning coloration.
Like other wasps, yellow jackets chew bits of wood and leaves to make a “paper” nest. The most likely place for a nest is a hole in the ground with a small single entrance. Nests can also be constructed hanging from a tree branch, a hole in a tree, under the eaves of a house, in the attic or in any other suitable place that is dry and not often disturbed. If you find a nest in your yard, due to the danger involved, it is recommended that you call a professional pest control operator to remove it.
Yellow jackets are renowned scavengers — eating road kill, rotting fruit, insects and our picnic scraps. They forage for food more than 1,000 feet from the nest and will attack if they sense a threat to themselves or their nest. If one lands on you in the course of searching for food, you are probably safe from being stung but swatting may stimulate their aggressiveness. Yellow jackets may also be attracted to brightly colored clothing. Unfortunately, they can sting more than once, or at least until they lose their stinger. They may also bite. Many people are allergic to the sting.
Several years ago was an especially critical one for yellow jackets in El Dorado County. It seemed that the aggressive insects invaded every picnic or backyard barbecue. I recall a late August birthday party at Cameron Park Lake where the pesky varmints attacked like they were F-16 jets with laser-guided, meat-seeking missiles. I heard many stories of folks stumbling upon yellow jacket nests and being chased and stung several times. One person I know was raking leaves and disturbed a nest. He was stung 18 times and rushed to Marshall Hospital. He survived, but is a lot more careful with his rake. Yellow jacket season begins anywhere from late March to May (depending on weather) and ends in the fall. The queens are first to emerge in spring time and select a nesting site to lay their eggs. About a month later the workers emerge and the queen retires to the nest to produce workers. By August or September each colony can attain a maximum size of up to 4,000 workers.
This last spring was one of the warmest on record. We all remember the bright sunny days of March and April and so do the yellow jacket queens. This warm weather in spring allowed more queens to survive. The high rate of queen survival means that this fall, there are lots of yellow jacket workers in the backyard and hovering around the barbecue.
Trapping is an effective way to limit yellow jackets. I have tried several traps and recommend the Rescue trap by Sterling. This trap is easy to use and comes with a pheromone that will attract yellow jackets. A protein bait, such as turkey ham, can be added to increase efficiency but should be replaced often. Avoid baits high in fat content because they spoil quickly and will actually repel yellow jackets Traps should be placed away from human activity as they will draw yellow jackets to them. Three to four traps will cover an average sized yard.
Mike Kobus is the owner/operator of Koby Pest Control. He can be reached at 530-626-6774