Q&A / 

Carpenter Bee Insecticides

Carpenter Bee Insecticides

It is time to mount an offensive against the carpenter bees. So what common insecticides will work for you? You have two choices, liquid or powder. You may more easily find one type than another at a store, so just get what you can. All of the chemicals listed below will eliminate the bees if you use them as directed.

Many experts feel it is best to use the chemicals after dark when the bees are in their nests. They relax at night and you can be assured that they will be hit with the insecticides. Here is a list of insecticides that are recommended by Darryl P. Sanders. He compiled this list in 1996 while he worked at the Department of Entomology at the University of Missouri-Columbia.

  • bendiocarb (Ficam) 1% dust
  • carbaryl (Sevin) 5% dust or 1% spray
  • chlorpyrifos (Dursban) 1% dust or 0.5% spray
  • cyfluthrin (Tempo) 0.1% spray
  • cypermethrin (Cynoff, Demon) 0.2% spray
  • permethrin (Flee) 0.5% spray

The name listed in the ( ) is the common name you will see on a bottle on the shelf. You can find these products at most full service garden stores, feed mills, or possibly a home center that has a decent lawn and garden area. Be sure to pay attention to the concentrations on the bottle. They need to match those listed above or be slightly stronger. If the bottle is labeled correctly, there should be good instructions that tell you how to use and mix the product for controlling carpenter bees. Note the different concentrations depending upon the use as a dust or a liquid spray.


The dusts are very effective. Try to use these if possible. You can fashion a primitive duster from small diameter aquarium air pump tubing and a turkey baster or a battery acid squeeze bulb. The dusts work well because the bees pick up the dust on their bodies as they go in and out of the nests. Liquid sprays can disappear into the wood grain shortly after you spray them. The liquid sprays are very good if you desire an instant kill of bees that are in the nests.

Be sure to test your duster apparatus before using it. Always pump small amounts of dust into the opening. Be very careful to make sure you are back from the hole so dust doesn't blast you in the face.

Keep in mind that you can always add more dust. You don't want to inhale a cloud of insecticide dust and freak out while you are on a ladder 15 feet in the air.

Don't expect immediate results from the dust. It can take days for it to work on the bees. They eventually get sick and die. Sit back and relax. Once you see activity diminish start thinking about repairing the holes in your outside trim.

Column B314


Leave a Reply

You have to agree to the comment policy.