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.
It also prevents musty odors. Sage repels many garden bugs like moths, ants, slugs, sticks, carrot flies and cabbage moths that are known to destroy vegetable garden. Rosemary repels lice, moths, carrot flies, mosquitoes, sliver fish and bean beetles. Both fresh and dried rosemary are effective. It is advisable to plant rosemary around your patio.