Neem oil is a botanical pesticide made from an extract of the plant Azadirachta indica. Since it doesn't strongly affect humans, mammals, or beneficial bugs, farmers use neem oil as an insecticide and miticide to keep away pests like aphids and white flies. Neem oil even protects crops from fungal infections such as mildew and rust. People use insecticide with neem oil to repel mosquitoes and lice.

The plant that gives us neem oil originates in Southeast Asia. People from these countries have long noted the benefits of crushing the leaves and stems against their skin to keep off biting insects like gnats. A wider industrial and commercial use was found for the potent oil by grinding the seeds of the neem plant. When the oil is distilled from seeds, its concentrated mixture contains high amounts of the active chemical azadirachtin.

Azadirachtin-rich neem oil gets sprayed on crops as an organic substitute for other harsher insecticides that might be carcinogenic or have limited uses. Neem oil repels harmful insects like white flies, gnats, aphids, mites, and weevils, as well as strengthening the crops against rust, scab, mildew, and blight. Edible crops of vegetables do not get poisoned when neem oil is used.

Neem oil makes the plants it touches taste bitter, so pests won't eat them, as a "contact" insecticide. Azadirachtin also interrupts insects' transitions between different stages of metamorphosis, such as growing from larvae to pupae. It prevents insects from developing a hardened exoskeleton. When the chemical gets absorbed through the roots of crops, it functions as a "systemic insecticide." That means crops don't need to be constantly re-sprayed.

The greatest benefit of using neem oil is that it doesn't harm beneficial insects. Butterflies, earthworms, and bees all help plants pollinate or absorb nutrients. Lacewings eat insects trying to feed on the crops. But these bugs won't have a negative reaction to neem oil or azadirachtin.

Neem oil has even made it into cosmetic and household products. Lotions and skin sprays use the oil as a mild insecticide that isn't likely to cause rashes. If you soak cotton balls in neem oil and place them in your closet, it will dissuade wool moths from devouring your clothes. While neem oil smells faintly of garlic, many people prefer it to stronger chemical alternatives.