Pyrethrum insecticide is made from the pyrethrum daisy, Tanacetum cinerariifolium or Chrysanthemum cinerariifolium, and is one of the most widely used natural insecticides in existence. The substance has been used for over 100 years to control mosquitoes and other pests in the home and garden. Pyrethrins, the active ingredients, are concentrated in the seeds and flowers of the daisy, and work as a contact insecticide. This means that the insect only has to be touched by the substance for it to take effect. Pyrethrum insecticide can be purchased from local home and garden centers, ordered online or made at home.

Growing Pyrethrum Daisies to Make Your Own Insecticide

Pyrethrum DaisyTo make pyrethrum insecticide at home, you'll need to grow pyrethrum daisies, as the volatile active ingredients degrade quickly once the flowers are cut. Available online and at many well-stocked garden retailers, the plants are easy to grow and can even be sown from seed, if necessary. Sow pyrethrum daisy seeds in spring after all danger of frost has passed, spacing each one 3 to 4 inches apart and planting twice as deep as the size of the seed. If seeds are not available, plant container-grown specimens directly in a prepared planting site after all threat of frost is over, spaced about 12 inches apart.

For the best results, choose a planting location that receives full sun and has very well-drained soil of average fertility. Water immediately after planting and seeds will germinate in 7 to 10 days if the soil is kept moist. Keep the soil moist for the first two weeks of growth for container-grown plants to allow them time to become established. After germination occurs or two weeks of growth have passed, reduce watering to once per week. Increase watering to twice per week during times of drought or extreme heat. No supplemental fertilization is typically required.

Making Pyrethrum Insecticide at Home

Once a crop of pyrethrum daisies is in full bloom, the blossoms can be harvested to make pyrethrum insecticide, as this is when the concentration of pyrethrins is at its peak. Pick the flowers carefully and hang them in bunches in a warm, airy place to dry. For the best results, harvest the flowers with their stems intact and hang upside down in water for 24 to 48 hours before drying to increase the strength of the pyrethrins. This isn't necessary but it will make for a stronger insecticide.

Crush the dried pyrethrum flowers in a mortar and pestle or use a blender. Try to get a fine powder, as the finer the end result, the more effective it will be against insects. To use, simply apply the pyrethrum insecticide powder to the leaves of infected plants by dusting with a shaving brush or something similar. For the best results, use the powder immediately after grinding, as the active ingredients deteriorate very quickly.

To make a spray pyrethrum insecticide, soak approximately 2 teaspoons of the powder in 4 cups of very warm water for around three hours. After this time period, add 1 tsp of dish washing liquid and the spray is ready to be used. Simply spray where needed, but avoid healthy plants, pets and children. Use immediately for the best results or within at least 12 hours of preparation. After this time, the active ingredients will no longer offer protection.