Instead of buying expensive chemical preparations to treat pest problems, it's possible to make mixtures from common household items. Making and applying mixtures takes some experimentation. See what works best for you.
* Insecticidal soap: This spray works well on small, soft-bodied, foliage-eating pests like aphids, mealybugs, scales, thrips, whiteflies and mites. It won't harm larger, desirable insects such as bees and ladybugs, although it can kill ladybug larvae.
Mix one-half to 1 tablespoon of a mild liquid dish detergent with a gallon of water. Spray the solution on a small section of the plant and wait half an hour to test for leaf damage. If all seems well, spray the top and underside of plant leaves. Wash the soap off the plants a few hours later if you are concerned about leaf damage.
* Fungicide: When applied on a regular basis, this mixture will rid your plants of fungus problems such as rust, powdery mildew and black spot. It works especially well on roses.
Mix 1 tablespoon of horticultural oil and 1 1/2 tablespoons of baking soda in a gallon of water. Spray on the upper and lower parts of leaves. Repeat every seven to 10 days.