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.
A weekly dusting of sulfur can prevent and treat garden rust disease. Neem oil, a botanical fungicide and pesticide, also controls rust. Some organic gardeners swear by baking soda for garden fungus control. The efficacy of baking soda spray may be enhanced by mixing it with light horticultural oil.