Many plants have insecticidal properties. Botanical products are extracts of these plants, which can be sprayed on crop to kill or repel insects.
A well-known example is the Neem tree (Azadirachta indica). All parts of this tree, but especially the grains, contain active ingredients, which can be used as insecticide. Neem is found to be active against a large number of pests, including the African bollworm (Helicoverpa armigera), Diamond-back moth (Plutella xylostella), thrips and aphids.
Another plant, well known for its insecticidal properties is Tobacco (Nicotiana tabacum). Extracts of tobacco leaves are effective against aphids and thrips.
Many other plants can also be used to prepare extracts with pesticidal properties. For example garlic, chili pepper (Capsicum) and onion.
An important advantage of botanical pesticides is that they are cheap and affordable for small-scale farmers.
Compared to synthetic pesticides, botanical products are generally safer to use, but care should be taken, as some plants contain very toxic substances. For example, the nicotine in tobacco is a highly toxic chemical.
Another advantage of botanical products is that they are not very persistent. Most of them will break down quickly under influence of high temperature or sunshine. Therefore they don’t have a long lasting contaminating effect on the environment.
A disadvantage of botanical products is that they are generally not specific. Many plant extracts will also kill or repel beneficial insects. Just like synthetic pesticides, the botanical products should thus be avoided and only be used as a last resort. However, if a farmer decides, after careful consideration, that active control of a pest is required, botanical extracts are usually a better choice than chemical pesticides.
