Why should carpenter bee holes not be plugged immediately after insecticide treatment?

The reasoning behind waiting to plug carpenter bee holes after insecticide treatment primarily revolves around effective insecticide penetration. When insecticide is applied to the holes, it needs adequate exposure to the target pests to ensure that it can work effectively. If the holes are plugged immediately, it can create a barrier that prevents the insecticide from fully penetrating the tunnels where the bees may be residing. This limits the treatment's effectiveness because the insects may not come into contact with the insecticide, which could allow them to continue their activity and cause further damage.

Additionally, plugging the holes too soon can also interfere with the ability to monitor any residual activity and ensure that all pests have been eradicated. This approach helps ensure that the treatment is comprehensive, making sure that the application works effectively against the carpenter bees.