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.
If your garden is bothered by any of the susceptible insects, Bt pest control might be something to consider. Controlling pests with Bacillus thuringiensis can be an effective and environmentally friendly way to treat your garden. Knowing about what Bacillus thuringiensis is and how and when it should be used is the key to its success.