Neem extracts are particularly suitable for use on vegetables and small scale field crops. If sufficient water and sprayers are available it is also possible to treat larger fields..

Numerous insect species are repelled by active ingredients in the neem seed. As they find the taste and smell unpleasant they avoid the plants that have been treated with neem extracts. Other insects die some time after having eaten leaves or other parts of the plant treated with these substances. They alter the behaviour in some insects or reduce their ability to lay eggs. Other pest species are affected minimally or not at all by the neem substances, probably as a result of their hidden biology.

The neem extract can be applied in two ways: When using a sprayer, the rough particles must first be filtered out of the mixture to prevent clogging the nozzle. This is done by covering a bucket or similar container with a coarse cloth or gauze through which the mixture is poured. The sprayer is filled with the filtered solution and spraying of the vegetable crops can begin. If no sprayer is available the extract may be applied with a straw brush. In this case, it need not be filtered. A brush made with fine, flexible straw is simply dipped into the solution and shaken over the plants until all the leaves are moistened. The effect of the neem substance lasts between 3 to 6 days, regardless of how it was applied.

The neem extract can be applied in two ways: When using a sprayer, the rough particles must first be filtered out of the mixture to prevent clogging the nozzle. This is done by covering a bucket or similar container with a coarse cloth or gauze through which the mixture is poured. The sprayer is filled with the filtered solution and spraying of the vegetable crops can begin. If no sprayer is available the extract may be applied with a straw brush. In this case, it need not be filtered. A brush made with fine, flexible straw is simply dipped into the solution and shaken over the plants until all the leaves are moistened. The effect of the neem substance lasts between 3 to 6 days, regardless of how it was applied.

Neem Oil based pesticides scores over chemical pesticides in many ways. Few of them are:

Resistance: Pest and Insects can not develop resistance again neem based pesticides.
Ecofriendly: Neem based pesticides are eco friendly as compared to their counter part chemical pesticides.
No residue: Neem Oil based pesticide are residue free.
MHI 3 Days: Neem based pesticides have MHI of just three days.
Economical: Contrary to belief, this organic pesticide are very ecnomical.
Effective: Chemical Pesticides fails on egg, where neem pesticides are very effective on eggs of harmful pests.
Broad Spectrum: Neem Oil based pesticides are effective against more than 600 types of insects and pests.

The term broad spectrum refers to activity against a wide range of pests, diseases, fungus, nematodes, etc. of Neem Oil and Neem Oil based Pesticides. This is in contrast to a narrow-spectrum pesticides which are effective only targeted pests.