Neem oil comes from the tree Azadirachta indica, a South Asian and Indian plant common as an ornamental shade tree. It can be extracted from most parts of the tree, but the seeds hold the highest concentration of the insecticidal compound. The effective compound is Azadirachin, and it is found in highest amounts in the seeds. There are numerous uses due to its anti-fungal and pesticide properties.
Neem oil insecticide works as a systemic in many plants when applied as a soil drench. This means it is absorbed by the plant and distributed throughout the tissue. Once the product is in the plant’s vascular system, insects intake it during feeding. It reduces insect feeding and acts as a repellent. It also interferes with insect hormone systems, making it harder for insects to grow and lay eggs. The compound causes insects to reduce or cease feeding, can prevent larvae from maturing, reduces or interrupts mating behavior and, in some cases, the oil coats the breathing holes of insects and kills them. Neem oil is a useful repellent for mites and used to manage over 200 other species of chewing or sucking insects according to product information, including: Aphids Mealybugs Scale Whiteflies. It is useful against fungi, mildews and rusts.
Some soft-skinned insect larvae may be killed by direct contact with the Neem oil spray. Adults are not killed by the growth regulating properties of azadirachtin but mating and sexual communication may be disrupted which results in reduced fecundity. It is also deemed helpful for other kinds of issues such as: Root rot Black spot Sooty mold etc.
Besides being an organic insecticide, using Neem oil allows you to target pests, specifically, as opposed to beneficial insects (for example, bees and lady bugs). More than 60 insect pests may be affected by azadirachtin including aphids, beetles, caterpillars, lace bugs, leafhoppers, leafminers, mealybugs, psyllids, thrips and whiteflies.