When damage becomes great enough to warrant emergency measures, organic gardeners often will want to use natural insecticides and various homemade botanical sprays, instead of synthetic organic chemicals.

Insecticides should be used only when needed and in strict accordance with label directions. A good understanding of insecticides enables you to use these materials effectively without harming you or the environment.

The following information may help gardeners select a natural insecticide for their specific needs.

Pyrethrum : Botanical Insecticide.
This slightly toxic insecticide is derived from the flowers of a species of chrysanthemum imported mainly from Kenya and Ecuador. The material causes rapid paralysis of most insects, but the insects usually recover unless the pyrethrum is used in combination with a synergist or other poison.

Pyrethrum mixed with synergists such as piperonyl butoxide or piperonyl cyclonene to increase toxicity and produce longer residual action is used extensively in space sprays, household sprays, crop sprays and dusts. This chemical is registered for use on most vegetables and fruits at any time during the growing season.

Nicotine : Botanical Insecticide.
Pure nicotine is a tobacco extract highly toxic to warm-blooded animals. The insecticide usually is marketed as a 40% liquid concentrate of nicotine sulfate, which is diluted in water and applied as a spray. Dusts can irritate the skin and are not normally available for garden use. Nicotine is used primarily for piercing sucking-insects such as aphids, whitefiles, leaf hoppers and thrips.

Nicotine is more effective when applied during warm weather. It degrades quickly, so can be used on many food plants nearing harvest. It is registered for use on a wide range of vegetable and fruit crops.