I have used the bug duster - battery powered dust applicator with food grade diatomaceous earth for 5 years to kill all kinds of bugs around the outside of the house. We have used an exterminator but the carpenter ants were still getting in (we're surrounded by trees). I simply spray it around the foundation of the house and under the deck. I do it after every rain event in case some of the DE has washed away. If there is a nest of ants, I flip over the rock with the duster in hand and spray away. I love the fact that if birds eat the insects, it will not harm them as it is not poison. After 5 years the battery died and I am thrilled batteries are available.