Local Plants Help Control Pests



Content: Save money. Control pests using local plants. Experiment with different plants, especially ones that have a strong smell and don’t suffer from insect damage.

Save money. Control pests using local plants. It may take extra time and effort, but there are advantages. Because they cost less than commercial insecticides you will have money to spend on other things, such as your children’s education. And homemade pest control solutions are often less harmful to the environment than store-bought chemical insecticides.

How can some plants help in pest control?

Plants have to protect themselves from their enemies, just as animals do. To understand how plants can help control pests we need to understand how plants protect themselves from insects.

We know how animals protect themselves. Many animals, such as deer, run to escape their enemies. Snakes have venom and can poison predators. Skunks give off a bad smell to keep predators away.

What about plants?

Plants can’t move the way deer and other animals can so they can’t run from their enemies. Do plants have any way of keeping their predators away or fighting their enemies? The answer is yes. Plants also have ways of defending themselves.

Some plants are poisonous and kill insects using naturally-produced chemicals, the way some snakes and spiders poison their enemies. For example tobacco (Nicotiana spp.) contains nicotine, chrysanthemum (Chrysanthemum cinerariafolium) contains pyrethrum and derris (Derris spp.) contains rotenone. These chemicals are poisonous to many pests and other organisms. The mammey tree (Mammea americana) of Central and South America also has chemicals which may be poisonous to many pests.

Other plants protect themselves the way a skunk protects itself. They produce chemicals which repel pests for reasons we don’t fully understand. For example, garlic (Allium sativum), wormwood (Artemesia spp.), tomato (Lycopersicon esculentum), and marigold (Tagetes spp.), all produce chemicals that insects don’t like. All these plants smell bad to insects the way skunks smell bad to us. So insects stay away. In some cases, even organisms that carry plant diseases stay away.

Experiment with plants for pest control

When you use a plant for pest control you may first have to process it. For example you may grind the leaves and add some water. Then you can spray the solution on your crop. If you don’t have a sprayer you could dip a broom, grass, or branches of any plant into the solution, and then sprinkle it on the crop you want to protect.

Common plants you know such as garlic, chile, and onion are not the only plants that have chemicals that repel insects. There are more than 2,000 species of pest-control plants in the world. That means that many of the plants you see every day could possibly be used to make insecticides. So farmers have a great opportunity to experiment with alternatives to chemical insecticides.

You may want to experiment with different plants that grow in your area even if you don’t know the names of them. To choose plants for experiment, first look for plants that have a strong smell. Second, choose plants that show no insect damage. For example, when you look at a field of damaged crops, you may see certain plants that aren’t attacked by insects. These plants probably contain some chemical repellent or poisonous substance and could be used to make pest control solutions.

When you decide which plant you want to experiment with, start with one part of the plant. If you don’t get good results, continue experimenting with other parts, other procedures, and then with other plants.

For example, start with the plant leaves. Many homemade pest-control recipes use plant leaves because they are easy to get at any time of the year. A good way to start is to grind them to a paste and add some water. Spray this solution directly on the crop you want to protect in a test plot. If you are using a sprayer you may need to strain the liquid and spray it immediately on your crop. Or soak the leaves in boiling water to extract its chemicals and then spray or sprinkle the solution on the plants.

Always try these new homemade sprays on just a few plants or a small test plot first. If you find something that is effective, then you can slowly increase the amount you apply.

If you are not satisfied with the results, choose another plant and keep experimenting. You will have to be a kind of detective to figure out which plants and mixtures work the best.

Pesticide safety

It is important to be extremely careful when you prepare and use these sprays and powders. They can be just as poisonous as the pesticides you buy. Follow the safety rules. Take the same precautions you would when you use any other pesticide.

  • Protect your hands with plastic gloves when preparing the mixture.
  • If you don’t have gloves, use small plastic bags tied to your wrist.
  • Never prepare insecticides in containers that hold food or drinking water.
  • When you apply insecticides always wear protective clothing.
  • Wash your hands and face thoroughly after applying your pest-control solution.
  • Do not eat or drink anything until after you wash your hands.

Learning to recognize pest-control plants and use them to protect your crop is worth the effort. You protect your crops using local resources, you save money, and you take better care of the environment.
Pesticide Safety Rules

  1. Store pesticides in original containers, never in food or drink containers. Store in a safe place, out of reach of children and animals. Keep away from food, water, and animal feeds.
  2. Follow the instructions and safety guidelines on the container. Obey the precautions. Use the amount instructed, in the correct manner. Know beforehand what to do in case of an accident.
  3. Don’t spray on a windy day. Never spray into the wind.
  4. Don’t let pesticides get on your skin. Wear protective clothing (cover all of your skin, if possible—including your feet, hands and head). Be especially careful when working with pesticide concentrates.
  5. If pesticide gets on skin, wash immediately. Get medical help if necessary. If it gets on clothes, remove clothes and wash the clothes before wearing them again. Always wash after using pesticides, even if you think none touched you.
  6. Don’t let pesticides get in your eyes. If possible, wear goggles or glasses.
  7. Avoid breathing pesticides in. (If possible, wear a mask, respirator, etc.)
  8. Don’t eat, drink or smoke near pesticides. Wash your hands and face with soap and water before eating, drinking or smoking.
  9. Wash all equipment used and store in a clean place.
  10. Don’t contaminate water (in rivers, wells, ponds, etc.) with pesticides.
  11. Don’t reuse empty pesticide containers. Rinse them at least twice, crush them and bury them.
  12. Keep people and animals out of recently sprayed areas.
  13. Don’t eat or sell food crops that have recently been sprayed.

Information sources

  • Thank you to Saleem Ahmed of the Resource Systems Institute, East-West Centre in Hawaii, for reviewing this script.
    Manejo integrado de plagas insectiles (Integrated pest management) (1992, 95 pages) by Ann Baier, Martin Bourque,
    Hermogenes Castillo and Ana Maria Xet, published by Altertec, 3a Avenida 5-27, Zona 1, Guatemala City, Guatemala.
    Preparacion y uso de plaguicidas naturales (Preparation and use of natural pesticides)(1992, 56 pages) by Mark Dupong, Rafael Solorzano G., and Hermogenes Castillo, published by Altertec, 3a Avenida 5-27, Zona 1, Guatemala City, Guatemala.
  • Handbook of plants with pest control properties (1988) by Michael Grainge and Saleem Ahmed, Resource Systems Institute, East-West Centre, Honolulu, Hawaii, U.S.A.
  • Natural crop protection based on local farm resources in the tropics and subtropics (1986, 186 pages), by Gaby Stoll, AGRECOL, c/o OKOZENTRUM, CH-4438 Langenbruck, Switzerland. Also available in French and Spanish.
  • Botanicals in rice cultivation (1991, 17 pages), published by the McKean Rehabilitation Centre, P.O. Box 53, Chiang Mai 50000, Thailand, and the Appropriate Technology Association, 143/171-2 Pinklao Nakornchaisri Rd., Bangkok 10700, Thailand.
  • Pyrethre: culture et utilisation domestique (Pyrethrum; cultivation and domestic use) (1980, 4 pages), Published by G.R.E.T. (Groupe de Recherche et d’Echanges Technologiques, 34 rue Dumont d’Urville, 75116 Paris, France.
  • “Botanical pesticides” (1989, 16 pages), in Sustainable Agriculture Newsletter, Vol. 1, No. 4, published by CUSO-Thailand, 17 Phahonyothin Golf Village, Phahonyothin Road, Bangkhen, Bangkok 10900, Thailand.
  • “Protection naturelle des cultures” (Natural crop protection) in Entre nous: bulletin d’,change d’information sur l’agriculture r,g,neratrice, Volume 4, No. 6, December 1991, published by Rodale International, B.P. A237 Thies, Senegal.
  • “Plaguicidas naturales” (Natural pesticides) in Ra¡ces, Year 5, No. 45, published by Asociaci¢n de Amigos del Pa¡s, 6a. Av. “A” 10-38 Zona 9, Apartado Postal 291, Guatemala City, Guatemala.
  • The following DCFRN scripts have more information about making insecticides from plants:
    • Neem seed spray protects crops – Package 30, Script 3
    • Make neem leaf spray at any time – Package 16, Script 6
    • Protection of stored grains with neem – Package 29, Script 3
    • Use chili peppers to control pests – Package 18, Script 8
    • Use garlic to control pests – Package 23, Script 1