Botanical Pest Controls

The following discussion is taken from the Late Spring edition of the Gardens Alive Catalog. For your free copy of this catalog, write to the Natural Garden Research Center, Highway 48, P.O. Box 149, Sunman, IN 47041. All the botanicals mentioned in this article are available from this company, However, you can find some or all of them at your local gardening center or through other mail order sources.

There is a misconception among many gardeners that organophosphates and other synthetic "chemical" insecticides are dangerous, while botanical and mineral insecticides are not. This is not necessarily true. Some botanicals, such as Insecticidal Soaps, are nearly harmless to mammals. But, in fact, Nicotine Sulfate and Rotenone are more toxic than, say, the chemicals Malathion or Carbaryl (Sevin).
Then why do we sell botanicals? Unlike many synthetic chemicals, most botanicals decompose quickly in the garden, broken down by oxygen and sunlight. This means their residues do not endanger our soil, our water supply, pets, people or wildlife. And it means there is somewhat less risk to beneficial insects which might come in contact with the poisons, even though most are broad-spectrum insecticides. This quick breakdown is the main reason botanicals were eventually abandoned in favor of synthetic chemicals. The chemicals knock out bugs over a longer period, but they also leave dangerous residues in the soil, in our water supply and on our food.
We believe that in some circumstances a botanical spray or dust may be the best response to a serious problem.
But only after:
	(1) you're sure which insect is causing the problem.
	(2) you've tried less drastic measures, like insect
	    predators and parasites, traps and barriers.
	(3) you've decided that saving your crop is worth the
	    risk of using botanical insecticides.
	(4) you've taken the normal safety precautions in using
	    them.

Organic gardeners and organic farmers do not always agree among themselves about which sprays and dusts are acceptable. Most use mild pest controls like Insecticidal Soaps. Nearly all the other botanical controls (derived from plants) are, to some extent, toxic. Any compound that can kill insects can, at least, make a person or a pet very sick.
Some of the botanicals, such as Rotenone in Asia and South America and Pyrethrum in Iran, have been used for many centuries. All of the following are used widely in the U.S. until synthetic chemicals became available in the 1940s or 1950s. Now that the synthetics have caused so much problem with the environment, botanicals are slowly coming back into favor.
ROTENONE

Rotenone is a resin derived from the roots of several leguminous plants, principally LONCHOCARPUS, A South American plant, and DERIS, from Malaysia. It is a broad-spectrum contact and stomach poison, affecting nerve and muscle cells. It causes insects to stop feeding and die within a few hours or days. Rotenone is extremely toxic to fish, but when accidentally eaten by humans and other animals, Rotenone is broken down by the liver. Inhaling large amounts of Rotenone, however, can be dangerous.
Rotenone, available in 1 per cent and 5 per cent concentrations, is most useful as a spray or dust against beetles and caterpillars that feed on leaves. It has been used successfully by farmers against Colorado potato beetles when the pests become resistant to all the government- approved synthetics. Vegetable gardeners use it to control aphids, asparagus beetles, bean leaf beetles, cucumber beetles, flea beetles, imported currant worms, raspberry cane borer, spittle bug and strawberry leaf beetle. In the stronger 5 per cent concentration, it also controls the birch leaf miner, blueberry maggot, codling moth, fire ant, grapeleaf skeletonizer, Japanese beetle, June beetle, leaf roller, leafhopper. pear psylla, and red spider mite.
SABADILLA

Sabadilla dust is the finely ground seeds of a tropical lily SCHOENOCAULON OFFIICINALE, from Central and South America. The alkaloids in Sabadilla affect the nerve cells of insects, causing paralysis and eventual, sometimes immediate, death. The dust is considered the least toxic of all registered botanical insecticides. In its pure, extracted, form, however, its active alkaloids are as toxic as the strongest synthetic insecticides. When ingested or absorbed through the skin and mucous membranes, it can make a person sick.
Sabadilla degrades quickly in air and sunlight and does not leave harmful residues in the environment.
Sabadilla is primarily a broad-spectrum contact poison, registered for use on cucumbers, melons and other vine crops; on cabbage, broccoli and related crops; on potatoes, peanuts and citrus fruits. It is best used to control harlequin bugs, squash bugs, stink bugs, blister beetles and other insects which, in their adult stage, are hard to control by other means.
Sabadilla also kills honeybees, which help pollinate your garden. Apply sabadilla in the evening after bees have returned to the hives.
RYANIA

Ryania comes from the stems of a South American shrub. A stomach poison, it causes insects to stop feeding soon after they eat it. It seems to be most effectively used in hot weather. Ryania is moderately toxic, but considered relatively harmless to humans and other mammals. It is used commercially to control citrus thrips and codling moths on fruit trees, and European corn borers on corn. It is also reportedly effective on corn earworms, cabbage worms and some other garden pests. Ryania is hard to find in stores but is available from Gardens Alive alone or in combination with Rotenone and Pyrethrin.
NICOTINE

Nicotine, derived from tobacco species, is one of the most toxic substances sold for use in the garden. It is extremely fast-acting, causing sever disruption and failure of the nervous system. In its pure form, Nicotine is easily absorbed through the eyes, skin and mucous membranes, and is very dangerous. If eaten, it is only slightly less hazardous.
Nicotine is used in greenhouses as a fumigant and in gardens as a contact poison to control soft-bodied sucking insects such as aphids, thrips and mites. It is effective on young scales and squash bugs, leafhoppers, pear psyllids, mealybugs, leaf miners, lace bugs and larvae of asparagus beetle and fungus gnat.
For any gardener, Nicotine Sulfate must be a weapon of last resort. Yet there are at least two characteristics to be counted in its favor:
First, no insect has ever developed an immunity to this poison.
Secondly, Nicotine sulfate biodegrades rapidly and has little residual effect.
For best results, add four teaspoons of horticultural spray oil per gallon of diluted Nicotine Sulfate. Keep your body and limbs covered, and wear protective gloves, goggles and mask when applying this product.
PYRETHRUM/PYRETHRINS

Pyrethrum is a broad-spectrum insecticidal powder made from the dried flowers of the CHYRSANTHEMEM CINERARIAEFOLIUM, commercial grown for the purpose in Kenya. Pyrethrins are the highly concentrated active compounds which are extracted from the daisy-like flower.
Pyrethrin is a fast-acting poison which disrupts the nervous system and causes paralysis. In the garden, it is used for its fast-acting knockdown effect - especially important when a particular insect invader is on the verge of destroying your crop. But many insects have the ability to metabolize Pyrethrin, and they can recover.
When eaten, Pyrethrin is not particularly toxic to humans and other mammals, but the appropriate care and follow product directions when using Pyrethrum flea powder on cats.
Among the advantages of Pyrethrin are its relative safety and its very low danger of residual environmental contamination. It breaks down very quickly from sunlight, moisture and oxygen. For garden use, fast-acting Pyrethrins are often combined with more lethal and longer lasting Rotenone and/or Ryania.
Some Pyrethrin products also contain piperonyl butoxide. Organic gardeners should know that this is a synergist and its safety is still in doubt.
INSECTICIDAL SOAPS

Insecticidal soaps, like all other soaps, are made from the salts of fatty acids, which are the main components of fats and oils in animals and plants.
Of these, certain fatty acids have been proven to have insecticidal properties. The active ingredients of Safer Soaps, for example, are potassium salts of oleic acid, which is abundant in olive oil. Scientists do not yet fully understand how these work to kill insect pests. Evidently the soap penetrates the insects outer coat or enter the respirator system and cause cell damage or disruption.
Generally, Insecticidal Soaps are no more dangerous or toxic to humans than the soaps with which you wash your hands or dishes. Sometimes, insecticidal soaps are combined with more toxic, synthetic chemicals to botanicals for garden use.
Safer soaps are the most commonly available insecticidal soaps and control soft-bodied insects (aphids, thrips, scales, whitefly, leafhopper nymphs and mites) which come in contact with the wet spray. Adult beetles, bees and wasps are not affected because of the hardness of their body cuticle.
Safer Soaps may be used on food crops right up to harvest time without danger to your family. When the soap dries, it loses its effectiveness. Residues break down quickly and pose no threat to the environment.
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