Formulations made of Neem oil also find wide usage as a bio-pesticide for organic farming, as it repels a wide variety of pests including the mealy bug, beet armyworm, aphids, the cabbage worm, thrips, whiteflies, mites, fungus gnats, beetles, moth larvae, mushroom flies, leafminers, caterpillers, locust, nematodes and the Japanese beetle. Neem Oil is not known to be harmful to mammals, birds or some beneficial insects such as earthworms, butterflies, honeybees and ladybugs. It can be used as a household pesticide for ant, bedbug, cockroach, housefly, sand fly, snail, termite and mosquitoes both as repellent and larvicide (Puri 1999). Neem oil also controls black spot, powdery mildew, anthracnose and rust (fungus).
For use as a bio-pesticide, pure Neem oil should be diluted at the rate of 1 teaspoon per quart, or 4 teaspoons per gallon of water (metric: 5.2 millilitres per litre) and used as a foliar spray or used as a soil drench at the rate of 1 liter per square meter of soil (3 ounces per square foot). Adding a surfactant greatly enhances its effectiveness. Ordinary liquid dishwashing soap may be used as a surfactant, added at the rate of 1 tablespoon per gallon.