September 18, 2003 at 1:47 p.m.
If you are a senior citizen, as I am, you don't remember yellow jackets when you were young, and for good reason. They were introduced accidentally to northeastern United States in the late 1960's. They have been in Minnesota for about 25 years. There is more than one kind of yellow jacket but it's the German yellow jacket that is sharing your picnic lunch with you. As I'm writing this article, they just announced on TV. that these bees have increased tenfold in the past couple of weeks and are worse this year than in the past. I have a couple of my own theories as to why this may be happening. One is because it's such a bumper year for apples and other fruits. The other is because the weather has been too dry. Wouldn't it be ironic if the latter were the case? A bumper crop of mosquitoes this summer due to the wet spring and now a record crop of yellow jackets because it was so dry this summer.
Yellow jackets are usually considered beneficial insects in the garden. They begin their life cycle as meat eaters of insects such as aphids on rose bushes to worms on ripening apples.
In September, the drones or worker bees are banished from the hive. They are no longer needed and they eat too much of the honey that is being saved for the winter. This means more bees are patrolling your yard and garden at this time of year looking for food thus increasing the risk of stinging.
As summer ends, the yellow jackets experience a shortage in their food supply (insects such as caterpillars and maggots). They also can get into fermenting fruit and become intoxicated. Intoxication changes their behavior and they become mean and aggressive. Yellow jackets are social insects and fiercely territorial, whether they are defending their nest or taking a drink from your pop can.
I'm glad I researched the yellow jackets because up until now I thought they were as worthless as mosquitoes.
I spend a lot of time in my raspberry patch in the fall because it's my main cash crop. Since I have everbearing raspberries, the fall crop is constantly blooming until the frost. The honey bees and bumble bees are busy pollinating blossoms from dawn to dusk. The yellow jackets occasionally pollinate but mainly they are looking for food.
I used to believe the false concept about yellow jackets that they are just a nuisance bee. However, an article from the Associated Press states that the yellow jacket is the most dangerous stinging insect around. It is blamed for between 50 to 100 deaths each year. There is another serious downside to this type of bee. The honey bee can only sting once because it loses its stinger after stinging. However, the yellow jacket can sting multiple times. I'm not going to get into allergic reactions from bees because I know very little about the subject. I do know that bee stings can be a little like poison ivy. There comes a point where repeated exposures or multiple bee stings can result in an increased risk of allergic reaction.
The best way to control the yellow jacket is to find their nest and proceed from there. The main problem with this particular bee is that it's not fussy about where it builds its nests. Also, if it's true that drones get evicted out of the hive, they may have a home away from home.
If you find the nest on the ground, first try pouring a soap and water solution into the hole. Any type of detergent will do. If that doesn't work, sprinkle chlorpyrifos dust into the opening or mix a liquid concentrate such as Sevin and pour it into the nest opening. Be sure the product you use has been cleared for lawn or soil use. Some use the Sevin in the power form and sprinkle it outside the nest.
Hanging nests on trees, shrubs or on buildings can be sprayed with an aerosol insecticide, such as resmethrin or propoxur (ex baygon) into the opening. Do this at night when bees are not so active. Repeat several times if necessary. Aerosols don't work well in hidden areas like behind walls, in attics, etc.
When I finished writing this article I went out to pick berries. The Pat Miles' show was on WCCO and they were talking about bees and bee stings. I realized that I had forgotten to mention that yellow jackets are in the wasp family and differ from bees in that they are meat eaters; while honey and bumble bees just gather pollen.
To learn more about this topic or others, go to the U of M Extension Service web page at www.extension.umn.edu and search. Or, you may call our Yard and Garden Line anytime and leave a message at (612) 624-4771. A Master Gardener will return your call. The Master Gardeners also staff the Extension Office on Monday from 4:30 to 8 p.m. Call (651) 674-4417 or drop by with your samples and gardening questions.
Applications for the 2004 Master Gardener Training program are now available from your county extension office. The deadline for Chisago County is September 19.