Hi Jela
Neem is being used to manufacture what is known as the natural or bio insecticide, that are environmental friendly and do not have any toxic effects on plants and soil. Neem insecticide are used to protect both food as well as cash crops like rice, pulses, cotton, oils seeds etc. Great for use on all crops, trees, plants, flowers, fruits, veggies round the home as well as organic and commercial growers. Active ingredient Azadirachtin, found in neem tree, acts as an insect repellent and insect feeding inhibitor, thereby protecting the plants. This ingredient belongs to an organic molecule class called tetranortriterpenoids. It is similar in structure to insect hormones called "ecdysones," which control the process of metamorphosis as the insects pass from larva to pupa to adult.
Neem oil and seed extracts are known to possess germicidal and anti bacterial properties which are useful to protect the plants from different kinds of pests. One of the most important advantage of neem based pesticides which differs it from its synthetic counterparts is the fact that it does not leave any residue on the plants. Neem pesticides are generally water soluble and help in the growth of the plants.
REgards
Ashwini