An oil extracted from the seeds of the neem tree is a powerful natural insecticide, capable of disrupting the life cycle of insects at all stages (adult, larvae, and egg), making it a great resource for the organic gardener.
Neem oil acts as a hormone disruptor and as an "antifeedant" for insects that feed on leaves and other plant parts. Neem oil is biodegradable and is nontoxic to pets, birds, fish, and other wildlife, and is effective against a variety of common garden insect pests, as well as being a natural fungicide that can combat powder mildew and other fungal infections on plants.
Inexpensive and can be easily found at many garden stores, Indian grocers or natural foods markets.
How to Apply:
To use neem oil as an insecticide, start out with a basic mixture of two teaspoons neem oil and one teaspoon of mild liquid soap shaken thoroughly with one quart of water, and then sprayed on the affected plant foliage.
Neem oil can also be used preventatively by spraying the leaves of plants that are often ravaged by pests, before they're actually infested. Spray (fine nozzles) from at least 12"-18" away as direct spraying may damage your foliage. (as oil blocks out the sun for photosynthesis) and the leaves may have black spots where a concentrate of Neem oil sits.
CAUTION: Neem oil can be slightly irritating to the eyes and skin. Azadirachtin, a component of neem oil, can be very irritating to the skin and stomach.