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.
Sabadilla : Botanical Insecticide.
Sabadilla is obtained from the seeds of a lily-Like plant and acts as both a contact and stomach poison for insects. It is not particularly toxic to mammals, but does cause irritation of the eyes and respiratory tract. A mask should be worn when working with this insecticide. This. material deteriorates rapidly upon exposure to light and can be used safely on food crops shortly before harvest. Sabadilla generally is used as a 5 to 20% dust or as a spray.
Rotenone : Botanical Insecticide.
Rotenone is extracted from the roots of derris plants in Asia and cube plants in South America. This general garden insecticide is harmless to plants, highly toxic to fish and many insects, moderately toxic to mammals and leaves no harmful residue on vegetable crops. It acts as both a contact and stomach poison to insects. It is slow acting, and in the presence of sun and air, its effectiveness is lost within a week after application. Wear a mask during application because rotenone can irritate the respiratory tract. Rotenone dusts and sprays have been used for years to control aphids, certain beetles and caterpillars on plants as well as fleas and lice on animals.
Other Pesticides
Gardeners have been using soap to control insects since the early 1800s. During the first half of the 19th century, whale oil soap and, more commonly, fish oil soaps were an important part of insect control. A recent test indicate Ivory liquid dishwashing detergent, diluted with water to a 1 to 2% solution, provide the most consistent control and is easy to mix.
There are also soaps available that are specifically formulated to control insects on plants. Thorough coverage of the plant and repeated applications may be necessary to bring insect populations under control. High rates of soaps and detergents may damage some varieties of plants. The most effective soaps have carbon chains of C-12 or C-18. Laurate (C-12) is the main component of most dishwashing liquids and various other products in common usage. The richest natural source of this is coconut oil.
Organic gardeners have been using a spray mixture containing onions, garlic and pepper mixed together to control insects for many years. Recent scientific research indicates the use of the combination of these materials has been erratic and, in many cases, ineffective for insect control. Sprays of food-derived substances do not appear to be good choices as a pesticide. However, some success may be achieved with them, but it is likely to be sporadic. Spraying several times a week might help to bring infestations under control. Control with one application should not be expected.
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