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.
16 Common Garden Pests. You can identify pest damage in one of two ways: You see the insect or the damage it causes. Use chemical sprays only as a last resort. Where possible, try pest traps and barriers, biological controls and organic sprays first. Garden Pests Organic.