Tony from Upstate, Ny writes
Demand CS is not a contact kill product, it is a residual product that can take a few days to start killing the carpenter bees. You could incorporate a dust insecticide like Delta Dust. It is water-resistant insecticide dust with the powerful active ingredient Deltamethrin, suitable for most common crawling and flying insect pests. Using insecticide dust directly in existing carpenter bee nests gives you the best chances of getting rid of carpenter bees that are already in the area. You can apply Delta Dust with the B&G Bulb Duster 1150. After this treatment, you can use Trebor Plastic Plugs - 3/8 inch 14 days after spraying and dusting to seal up existing holes. This allows time for the female bees to return to the nest, come into contact with the application, and spread the dust throughout the nest.
Answer last updated on: 06/07/2019
