The LowDown on Dursban • The LowDown on Dursban • The LowDown on Dursban • The LowDown on Dursban Alternatives to Using Chlorpyrifos By Kagan Owens

hlorpyrifos, the active ingredient in over 800 pesti atmosphere, it does not have the dangers associated with the use cide products, is used to control numerous pest prob of synthetic pesticides. lems. When looking for alternatives to using this chemi- Electrical currents can be used to kill insects that nest in the C TM cal you must remember that one chemical cannot be swiped out walls of a structure. The Electorgun uses low wattage, high for another. In order to identify an alternative to using voltage, and high frequency to kill the insects. It does not emit chlorpyrifos it is necessary to first identify the pest problem. microwaves, x-rays, ultraviolet rays or other potentially harmful It is important to remember radiation. Tests have shown the when controlling a pest problem gun to be very effective. Exist- to look for long-term solutions It is important to remember ing pest holes and holes drilled not just a temporary control. In- into the nests by the operator are stead of addressing the cause of when controlling a pest problem used as entry points for the elec- pest problems, many pesticides tricity. Tests show that whereas only treat the symptoms, without to look for long-term solutions some termites die immediately, changing the structural problems not just a temporary control. others may take weeks to die, but that create an environment con- that they all die eventually. ducive to their existence. Pesti- Fatty-acid soap and water cides are often ineffective over the long term and the most com- can be used to control pests. The fatty acids in soaps serve as an mon pests are now resistant to many insecticides. insecticide killing pests on contact. Aphids, which attract ants, Simple changes in your environment can significantly reduce can be controlled by treating the aphids directly with insecti- pest populations. Before reaching for a pesticide, monitor the cidal soaps. Direct action against individual fire ant nests in- pest population, make structural repairs, use proper sanitation clude pouring boiling or soapy water directly into the hole. inside and outside, and modify the pest’s habitat. Any openings Beneficial nematodes are microscopic soil-dwelling that pests are using to access the structure should be caulked, worms that actively search for insects like pre-adult fleas, fire screened or repaired. Some outdoor pests are attracted to spilled ants, or termites in the yard. After invading the larvae or pu- greasy or sugary liquids, improperly stored garbage, untended pae, they release a bacterium that kills the host within 48 pet foods or explosions of naturally-occurring food sources like hours. The nematodes then feed on the pest’s body, repro- aphids or scale infestations on nearby plants. Efforts to elimi- duce and seek out more pests. When all larvae and pupae are nate food sources may eliminate the pest problems. killed, the nematodes die off and biodegrade. Numerous pest Following is a brief description of some alternatives to using problems can be controlled or eliminated by using biological chlorpyrifos to control common pest problems. Use Table 1 to controls that have a minimal impact on non-target species identify which alternatives can be used to eradicate a specific and offer long-term solutions. pest problem. Milky spore disease, Bacillus popilliae is a nontoxic way to control grubs. Commercial milky spore dust is made Non-Toxic Solutions by inoculating beetle grubs with the disease and then ex- Heat treatments are effective in controlling pest popula- tracting the spores, which resemble dust or powder when tions for those pests that have minimum and maximum tem- dry. The spores can be applied any time except when the peratures beyond which they cannot survive. Heat treatments ground is frozen or a strong wind is blowing. Grubs be- require raising the temperature of a structure to 120 degrees come infected when they feed on the thatch or roots of F or more. Special equipment composed of a heating unit, grass where the spores have been applied. As the infected blowers and ducts carries the heat to the locations in the struc- grubs move about in the soil, then die and disintegrate, ture where the pests are causing damage. Heat treatment field they release one or two billion spores back into the soil. tests have killed insects inside wood without damaging the This spreads the disease to succeeding generations of grubs. building or furnishings, although certain sensitive appliances If the conditions are right, grub population high and feed- should be removed as a precaution. ing vigorously, and soil is at least 70 degrees F and very Cold treatments of liquid nitrogen can also eradicate pests moist, the disease can spread through the grub population that live in a narrow temperature range. Liquid nitrogen can be in a week or two. In general, however, the disease should pumped into walls, which freezes the pest, killing them, then not be thought of as a quick knockdown insecticide. It may warms and evaporates. Because nitrogen is a natural part of our take a season or two before it has a substantial impact.

Vol. 20, No. 1, 2000 Pesticides and You Page 19 Beyond Pesticides/National Coalition Against the Misuse of Pesticides The LowDown on Dursban • The LowDown on Dursban • The LowDown on Dursban • The LowDown on Dursban

Bacillus thuringiensis (B.t.) is a naturally occurring soil Diatomaceous earth and silica aerogels are insecticidal dusts bacterium; it is a spore-forming rod and an insect pathogen. that kill pests by breaking through their outer cuticle, which Different strains are toxic to particular kinds of insects. There protects them from excess moisture loss. When the dust comes are nearly 400 registered products that have been marketed in contact with the pest, it abrades their outer shell, dehydrating in the country, providing effective control of such major in- and finally killing the pest. Because the dusts are inorganic, they sect pests as gypsy moths, mosquitoes, blackflies, and many can remain effective for a very long time. Although they are made others. These B.t. strains are only effective against insects in of inert material and are relatively safe, care should be taken to their larval feeding stages, since B.t. must be ingested to be avoid inhalation. Be aware that they have been combined with effective. Depending on how much B.t. is ingested, insect larva pyrethrin insecticides in various products; and there are serious soon stop feeding and health concerns asso- are dead in a few days ciated with the use of to a few weeks. B.t. is If pesticides are used, it is best to go with baits or pyrethrins. With diato- completely biode- maceous earth, it is im- gradable, and does crack and crevice spot treatments and use the least portant that natural, not persist in the di- not swimming pool gestive systems of grade, be used. Swim- birds or mammals. toxic pesticide available and only after non-toxic ming pool grade has There is no evidence been refined in such a that B.t. goes on to re- alternatives have been tried manner that makes it produce in the wild. more harmful to hu- B.t.’s short biological man lungs. Silica half-life and high specificity makes the development of field aerogels are higher in acute toxicity and tend to kill insects more resistance much more unlikely than with chemical pesticides quickly than diatomaceous earth. Silica aerogels are toxic to fish, if used in a targeted fashion. so they should not be applied where they could run off into a stream, pond or lake. Least Toxic Pesticides Botanical pesticides are derived from plants that are Because of the high toxicity of conventional pesticides and known to have insecticidal properties. It is important to re- the high levels of exposure to people and pests that result from member that just because a pesticide is derived from a plant their use, it is wise to avoid them. Pesticides are products that does not mean that it is safe for humans and other mammals are designed to kill living organisms and should be treated with or that it cannot kill a wide variety of other life. Many botani- caution. If pesticides are used, it is best to go with baits or crack cal insecticides are formulated with synergists. These have and crevice spot treatments and use the least toxic pesticide avail- no insecticidal effect of their own, but serve to enhance the able and only after non-toxic alternatives have been tried. insecticidal effect of the botanicals. Carefully read the labels Boric Acid is a low-toxicity mineral with insecticidal proper- on all products before use to make sure that they do not also ties. It does not evaporate or volatilize into the air or pose the contain toxic pesticides. Some botanical pesticides can be quite considerable health concerns associated with synthetic pesticides; toxic to humans and should not be used. Neem oil and garlic however it can still pose health hazards and should be used with oil are two least-toxic botanical pesticides listed below. Oth- care. Insects travel through the boric acid, which adheres to their ers that can also be used as a last resort are citrus oils, mint legs. When the insects groom themselves, they then ingest the oil, pine oil and herbal extracts. poison, which causes death three to ten days later of starvation Neem oil, extracted from the tropical neem tree, contains and dehydration. As long as the material is not allowed to be- insecticidal properties that are composed of a complex mix- come wet, its continuous presence ensures that hatching insects, ture of biologically active compounds. It has a strong, unpleas- which sprays commonly spare, are exposed and die. Because ant odor and a bitter taste. Its various active ingredients act as boric acid is a stomach poison, don’t expect immediate results – repellents, feeding inhibitors, egg-laying deterrents, growth it may take weeks or even months to completely get rid of the retardants, sterilants and direct toxins. Neem has both contact pest problem. While boric acid is somewhat slower acting than and systemic action in plants. The active ingredients biode- the synthetic pesticides, like chlorpyrifos, diazinon, or pyrethrins, grade rapidly in sunlight and within a few weeks in the soil. it is highly effective over a long period of time. At least one study Garlic oil exhibits antibacterial, antifungal, amebicidal and has shown that the combination of heat, 110 degree F for two insecticidal qualities. Although garlic oils kill pest insects and hours with boric acid, will increase the speed at which the Ger- some pathogens, it also kills beneficial insects and microbes. man cockroach is killed. As with any pesticide, keep boric acid Thus, it is not recommend as an all-purpose spray for out- pesticide products out of reach of children and only use it in door use. locations where it will not come in contact with people or ani- If you have a pest problem, contact Beyond Pesticides/NCAMP mals, such as in cracks and crevices, behind counters, and in for a detailed information packet on how to control the pest using baseboards. non and least toxic methods.

Page 20 Pesticides and You Vol. 20, No. 1, 2000 Beyond Pesticides/National Coalition Against the Misuse of Pesticides The LowDown on Dursban • The LowDown on Dursban • The LowDown on Dursban • The LowDown on Dursban

Table 1. Non- and Least Toxic Alternatives to Using Chlorpyrifos

Ants Gypsy moths Heat treatment Microbial insecticide: Bacillus thuringiensis Cold treatment Spinosad Electrical current Fatty acid soap Japanese beetles/grubs Beneficial nematodes, Steinernema sp. Milky spore Spinosad Beneficial nematodes Diatomaceous earth Botanical pesticides: neem Boric acid Botanical pesticides: d-limonene, mint oil, herbal ex- Mosquitoes tracts, orange oil, pine oil, garlic Carbon dioxide traps Bat houses Chinch Bug Purple martin houses Beneficial fungus, Beauveria spp. Microbial insecticides: Bacillus thuringensis Israeliensis, Beneficial wasp, Eumicrosoma beneficum and Bacillus sphaericus Insecticidal soap Mosquito fish, Gambusia affinis Silica aerogel Botanical pesticides: herbal extracts, neem

Cockroaches Termites Electrical currents Heat treatment Heat treatment Cold treatment Beneficial fungus: Metarhiziumanisopliae Termite shield Diatomaceous earth Electrical currents Boric acid Beneficial nematodes, Steinernema carpocapsae Botanical pesticides: orange oil, mint oil, herbal oil, Microbial termiticide: Metarhizium anisopliae neem Spinosad Diatomaceous earth Crickets Silica gel Beneficial fungal pathogen: Beauveria bassiana Boric acid Insecticidal soap Botanical pesticides: neem Diatomaceous earth Boric acid Wasp and Hornets Botanical pesticides: neem Physical traps Insecticidal soap Fleas Boric acid Beneficial nematodes Diatomaceous earth Insecticidal soap Silica aerogels Boric acid Botanical oil: mint oil Diatomaceous earth Silica aerogel Webworms/Cutworms/Caterpillars Botanical: limonene and herbal oil extract Beneficial Nematodes Microbial insecticide: Bacillus thuringiensis Flies Spinosad Beneficial nematodes, parasitoids, parasitic mites Beneficial Endophytic fungi Botanical repellents Insecticidal soaps Diatomaceous earth Free roaming chickens Silica aerogels

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