Neem oil has many complex active ingredients. Rather than being simple poisons, those ingredients are similar to the hormones that insects produce. Insects take up the neem oil ingredients just like natural hormones.

Neem enters the system and blocks the real hormones from working properly. Insects “forget” to eat, to mate, or they stop laying eggs. Some forget that they can fly. If eggs are produced they don’t hatch, or the larvae don’t moult.

Obviously insects that are too confused to eat or breed will not survive. The population eventually plummets, and they disappear. The cycle is broken.

How precisely it works is difficult for scientists to find out. There are too many different active substances in neem oil and every insect species reacts differently to neem insecticide.

Neem oil does not kill beneficial insects for example butterflies, ladybugs, earthworms & bees. Only chewing and sucking insects are affected. It is certainly fascinating.

Like real hormones, neem  works at very low concentrations, in the parts per million range. A little neem oil goes a long way.

But this is not something that happens over night. People spray neem oil as an insecticide and expect everything to die instantly, because that’s what they are used to from chemical poisons. When that does not happen they conclude neem does not work.

It does work! Give it time to work. It’s a much smarter way to deal with insect pests than to just kill everything.