Peppermint oil spray repels ants and gets rid of other hard-bodied insects. Oregon State University recommends mixing one part peppermint oil with 10 parts water to produce a spray that gets rid of ants. Experts at the University of Hawaii suggest a similar mixture containing 2 tablespoons of liquid soap, 2 tablespoons of peppermint oil and 1 gallon of water to get rid of insects with hard bodies, such as weevils. The peppermint oil helps the mixture penetrate insect shells, while the soap reduces surface tension and helps the mixture smother insects.
This is cheap if you grow your own mint and use that.
Thankyou for your advise