In such cases the weeps consist of small-diameter plastic, clay or metal pipes extending through the wall to a layer of porous backfill. Typically, weeps are arranged to direct water which may have entered an assembly from outside back to the outside.
A few of several safe household chemicals to use are vinegar, dishwashing soap and rubbing alcohol, according to an Oregon State University Extension Service publication called Using Home Remedies to Control Garden Pests, (EC 1586). The publication, complete with photos, is available free of charge online.
To eliminate insects around the garden, take an empty 2 liter soda bottle with 1 cup apple cider vinegar and 1 cup sugar. Slice up a banana peel into small pieces, put into the bottle, add 1 cup cold water, shake. Tie a piece of string on a low tree branch or place it on the ground to kill pests.