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.
Repellant plants emit odors or chemicals that kill or repel pests, or attract beneficial insects that prey on garden predators. Some of these plants can be made into teas or foliar sprays that are effective as insect repellents or fungicides. Planting flowers that repel garden pests offers an extra bonus of brightening up the garden with beautifully colored blooms and foliages.