Pest Management Guidelines

Pesticides include insecticidal soaps, horticultural oils, biopesticides, botanicals and minerals, and synthetic chemical pesticides and insect repellents.

Minimum-risk pesticides

The EPA has identified some pesticides as minimum-risk pesticides, and these products are exempted from the requirements of FIFRA (the Federal Insecticide, Fungicide, and Rodenticide Act). Other criteria must be met before a product is considered minimum risk. The inert ingredients in any such product must be on the list in the most current List 4A published in the Federal Register, which is updated periodically. For a copy of the list, write to Registration Support Branch (4A Inerts List), Registration Division (7505C), Office of Pesticide Programs, Environmental Protection Agency, 401 M St., SW, Washington, DC 20460.

All of the following conditions must be met for products to be exempted under this section:

· Each product containing the substance must bear a label identifying the name and percentage (by weight) of each active ingredient and the name of each inert ingredient.

· The product must not bear claims either to control or mitigate microorganisms that pose a threat to human health, including but not limited to disease-transmitting bacteria or viruses, or claims to control insects or rodents, carrying specific diseases, including, but not limited to, ticks that carry Lyme disease.

· The product must not include any false or misleading labeling statements.

Products containing the following active ingredients are exempt from the requirements of FIFRA, alone or in combination with other substances listed in this paragraph, provided that all of the above criteria are met.

Castor oil (U.S.P. or equivalent)

Cedar oil

Cinnamon and cinnamon oil

Citric acid

Citronella and citronella oil

Cloves and clove oil

Corn gluten meal

Corn oil

Cottonseed oil

Dried blood

Eugenol

Garlic and garlic oil

Geraniol

Geranium oil

Lauryl sulfate

Lemongrass oil

Linseed oil

Malic acid

Mint and mint oil

Peppermint and peppermint oil

2-Phenethyl propionate (2-phenylethyl propionate)

Potassium sorbate

Putrescent whole egg solids

Rosemary and rosemary oil

Sesame (includes ground sesame plant) and sesame oil

Sodium chloride (common salt)

Sodium lauryl sulfate

Soybean oil

Thyme and thyme oil

White pepper

Zinc metal strips (consisting solely of zinc metal and impurities)

Insecticidal Soaps

These specially formulated soaps contain potassium or sodium salts of certain fatty acids. They have become popular because of their low toxicity to humans, pets, and many beneficial insects.

Insecticidal soaps are one of the safest choices available for controlling pests in the garden or on ornamental plants. They control adelgids, aphids, mealy-bugs, whiteflies, mites, and other pests.

Insecticidal soaps work only on contact, so the spray solution must coat the pest. Once the spray has dried, an insect will not be harmed by walking over the residue. For example, spraying only the upper leaf surface will leave whiteflies alive and healthy because they usually feed on the undersurfaces of the leaves. Whitefly immature stages move little or not at all and will not be killed by contact with the wet material.

Spray only when and where an infestation appears, not as a preventive measure. Symptoms such as leaf or shoot distortion, sooty mold, and holes in leaves require further investigation to determine the cause and the extent of an infestation. Once you find the pest, treat only affected plants or spots.

Watch for phytotoxicity, an adverse plant reaction, or injury from the soap treatment. Symptoms on foliage include yellow or brown spotting, “burned” tips, and yellow or brown scorching on leaf edges. Soap spray may also cause marking on certain pome (e.g., apple, pear) and stone fruit varieties. Phytotoxicity is perhaps most people’s greatest concern when using insecticidal soap.

Avoidance of Plant Injury

1. Do not treat plants that are under stress. Drought is a major stress factor. Newly planted ornamentals, transplants, and unrooted or newly rooted cuttings are under stress and should not be sprayed until they are well established. Conifers are particularly susceptible when under drought stress. Make sure plants are well watered before treatment.

2. Avoid treating sensitive plants.
The following plants may show phytotoxic reactions after treatment:

Horsechestnut	Aesculus hippocastanum
Mountain ash	Sorbus americana
Japanese maple	Acer palmatum
Gardenia	Gardenia spp
Bleeding heart	Dicentra formosa
Sweet pea	Lathyrus odoratus
Maidenhair fern	Adiantum pedatum
Crown of thorns	Euphorbia milii
Lantana	Lantana spp.
Nasturtium	Nasturtium spp.
Easter lily (during bud formation)	Lilium longiflorum

Certain varieties of azalea, begonia, camellia, fuchsia, geranium, and impatiens may be sensitive. Rinse these plants with a clean water spray if they show signs of wilting within a few hours after treatment. Test a small portion of palms, delicate ferns, ornamental ivies, and succulents before treating an entire plant or area.

3. Wait for new growth to harden off before treating. Tender, young foliage of evergreen trees or shrubs is especially sensitive. Fruit and nut trees in bloom should not be sprayed. If in doubt, test a small part of the plant first. If the plant is sensitive, phytotoxic symptoms will appear within 48 hours.

4. Do not apply if the temperature is above 90° F or the plant is in full sun. High temperatures and high relative humidity may increase plant stress and therefore sensitivity. The best time to apply insecticidal soap is early morning.

Compatibility with Other Pesticides and Fertilizers

Insecticidal soap is compatible with many pesticides but should not be mixed with rotenone-based insecticides, Manzate, Dithane, lime sulfur, copper sulfate, or copper fungicides such as Bordeaux mixture. It should also not be combined with concentrated mineral fertilizers for spraying on foliage.

Compatibility with Water

Use soft water to dilute the soap. Hard water is unsatisfactory because soap combines with and is precipitated by certain minerals, especially calcium, iron, and magnesium, found in hard water. Test water by allowing a quart of the prepared spray solution to stand for 15 minutes. A scum or “curd” of soap scale on the surface indicates hard water and the need for a water conditioner. The solution should be a light, milky color.

Horticultural Oils

These highly refined petroleum oils are manufactured specifically to control plant pests. They are paraffinic, degrade rapidly through evaporation, and have very low toxicity to humans and wildlife when used properly.

Horticultural oils, applied both in the summer and when plants are dormant, have gained wide acceptance in pest management programs. They are relatively safe for plants and the environment and control many insect and mite pests. They are also relatively nontoxic to the applicator and leave no toxic residue.

Horticultural oils interfere with respiration and membrane function, causing suffocation, and disrupt feeding activities of certain insects and mites. Complete coverage of the infested parts of the plant is essential. Horticultural oils are most effective against eggs, immature forms, and soft-bodied adults. Aphids, scales, mealybugs, leafhoppers, whiteflies, mites, and eggs of almost all species are readily killed.

Several grades of horticultural oil are available. Some are strictly limited to dormant use; others can be applied to actively growing plants in spring and summer. Most trees can be treated in the summer, but check the label to be sure. Under adverse spraying conditions such as high heat and relative humidity, sensitive species may suffer from phytotoxicity. The following plants appear to be sensitive: maples, hickories, and black walnut (dormant sprays); smoke tree and certain varieties of azalea (summer sprays); and cryptomeria (both). The following plants show a tendency toward sensitivity: beech, redbud, spruce, and Douglas fir (dormant sprays); savin junipers and photina (summer sprays); and Japanese holly (both). Glaucus evergreens (those with a bluish bloom) may temporarily lose their blue color if oil is applied, and the natural bloom may not return for one to two years. Never spray when trees are under stress or temperatures are expected to be 90° F or above.

A preventive application in late winter and early spring when trees are dormant can save valuable time later in the season. The oil is applied to above-ground plant parts and is effective against scales, adelgids, and mites in their overwintering stages. Oil should not be applied to plants for 48 hours before or after freezing temperatures occur or are predicted.

Spring and summer applications are safe on a wide variety of plants when used properly. Phytotoxicity may result if plants are under moisture stress. The biological stage of the pest will determine whether a dormant or summer application is needed.

Pests that can be controlled by horticultural oil include:

Aphids

Balsam twig aphid

Cooley spruce gall adelgid

Cottony maple scale

Cottony taxus scale

Eastern spruce gall adelgid

Elongate hemlock scale

Euonymus scale

European red mite

Fletcher scale

Golden oak scale

Hemlock scale

Hemlock woolly adelgid

Juniper scale

Magnolia scale

Maple bladdergall mite

Oystershell scale

Pine bark adelgid

Pine eriophyid mites

Pine needle scale

Pine tortoise scale

Rust mites

Spruce spider mite

Twospotted spider mite

White prunicola scale

Biopesticides

Biopesticides are certain pesticides derived from natural materials such as animals, plants, bacteria, and certain minerals. For example, canola oil and baking soda have pesticidal applications and are considered biopesticides. At the end of 1998 there were approximately 175 biopesticide active ingredients and 700 products. Biopesticides fall into three major classes*:

1. Microbial pesticides consist of a microorganism (e.g., a bacterium, fungus, virus, or protozoan) as the active ingredient. Microbial pesticides can control many different kinds of pests, although each separate active ingredient is relatively specific for its target pest(s). For example, certain fungi control certain weeds; other fungi kill specific insects.

The most widely used microbial pesticides are subspecies and strains of Bacillus thuringiensis (Bt). Each strain of this bacterium produces a different mix of proteins and specifically kills one or only a few related species of insect larvae. Whereas some Bt’s control moth larvae found on plants, others are specific for larvae of flies and mosquitoes. The target insect species are determined by whether the particular Bt produces a protein that can bind to a larval gut receptor, thereby causing the insect larvae to starve.*

Microbial insecticides are applied as sprays, dusts, or granules just as conventional pesticides are (see Application Equipment, Chapter 1). Microbials may kill insects a little more slowly than do conventional pesticides. For example, when a caterpillar ingests Bt, it will continue to feed until the Bt toxin is activated in its gut and will remain alive on the plant for a few days. Because Bt does not reproduce and persist in the environment, it must be applied at regular intervals, much like synthetic insecticides.

2. Plant-pesticides are pesticidal substances that plants produce from genetic material that has been added to the plant. For example, scientists can take the gene for the Bt pesticidal protein and introduce the gene into the plant’s own genetic material. Then the plant, instead of the Bt bacterium, manufactures the substance that destroys the plant. Both the protein and its genetic material are regulated by the Environmental Protection Agency (EPA); the plant itself is not regulated.*

3. Biochemical pesticides are naturally occurring substances that control pests by nontoxic mechanisms. Conventional pesticides, by contrast, are generally synthetic materials that directly kill or inactivate the pest. Biochemical pesticides include substances such as insect sex pheromones that interfere with mating as well as various scented plant extracts that attract insect pests to traps. Because it is sometimes difficult to determine whether a substance meets the criteria for classification as a biochemical pesticide, the EPA has established a special committee to make such decisions.*

Biochemical products also include hormones such as growth regulators and enzymes. Insect growth regulators (IGRs) are nontoxic. They disrupt the balance in the insect between juvenile hormone, which regulates development, and the hormone that regulates emergence into adulthood, causing abnormal pupation or adult development. IGRs kill isolated populations of insects over a period of months or even years, but they may fail if new individuals join the population.

Advantages of using biopesticides*

· Biopesticides are usually inherently less harmful than conventional pesticides.

· Biopesticides generally affect only the target pest and closely related organisms, in contrast to broad-spectrum, conventional pesticides that may affect organisms as different as birds, insects, and mammals.

· Biopesticides are often effective in very small quantities and often decompose quickly, thereby resulting in lower exposures and largely avoiding the pollution problems caused by conventional pesticides.

· When used as a component of integrated pest management (IPM) programs, biopesticides can greatly decrease the use of conventional pesticides while crop yields remain high.

To use biopesticides effectively, however, users need to know a great deal about managing pests.

Botanical and Mineral Pesticides

Botanical pesticides are derived from plants; some, such as nicotine, are as toxic as many synthetic chemical pesticides or more so. Remember, all pesticides are poisonous to some forms of life.

Organic gardeners like botanicals because they are relatively short-lived in the environment and act quickly on insects. If residual action is needed, botanicals do not provide adequate protection. The following botanicals are readily available.

Pyrethrum products are made from the ground-up flowers of a certain type of chrysanthemum. Pyrethrins are the toxins extracted from the chrysanthemum flowers. They decompose rapidly when exposed to light, air, and moisture. Pests are stimulated to move from hiding places when hit with the spray, but they may be only temporarily paralyzed and recover quickly. Synergists combined with pyrethrins may block an insect’s ability to recover, but some synergists are toxic. The correct dose is important - be sure to follow instructions exactly when using these products.

Ryania, extracted from a tropical shrub, is a contact and stomach poison. It does not harm beneficial mites, lacewings, lady beetles, or parasitic wasps. Ryania is usually applied as a dust and is most effective in hot, dry weather. Rain washes it off plants. Its manufacture is dwindling, however, and Ryania may not be available in the future.

Sabadilla, extracted from the seeds of a plant in the lily family, is also a contact and stomach poison. It has little effect on common beneficials and is relatively nontoxic to humans and other mammals. Sabadilla is most effective against leafhoppers and true bugs. It breaks down rapidly in sun-light and air, lasting only about one day.

Rotenone is made from the ground roots of tropical plants. Cubé is the only commercial brand currently being sold, available as a dust or spray. Rotenone acts as a contact or stomach poison to insects. It is highly toxic to fish—do not use in areas where it may get into waterways—and moderately toxic to humans and most animals. It is not toxic to honey bees but will kill some beneficial insects. Formulations lose effectiveness within approximately one week of application.

Mineral pesticides include copper dust and sulfur. Sulfur controls plant disease organisms that cause black spot, scab, rust, powdery mildew, brown rot, and others. Bordeaux mixture is the product of a reaction between copper sulfate and lime. The mixture is sprayed to form a protective membranous coating over plant parts. It controls pathogens that cause anthracnose, downy mildew, cankers, and other diseases.

Diatomaceous earth is a dust made from fossilized shells of tiny aquatic organisms. The particles pierce the exoskeletons of soft-bodied insects, causing them to desiccate. The dust is nonselective, killing both harmful and beneficial insects. It loses its effectiveness if it gets wet, and another application is necessary.

Synthetic Chemical Pesticides

Synthetic chemicals are those made by humans. They have helped to increase the quality and diversity of food available to us and to improve human health by controlling disease vectors. Many synthetic pesticides have been developed since the discovery of DDT in the 1940s. These include insecticides such as malathion, carbaryl, and the synthetic pyrethroids; fungicides such as chlorothalonil and mancozeb; and herbicides such as 2,4D and glyphosate. In some instances, synthetic chemical pesticides may be the best choice for your pest problem, but avoid exposing people, pets, and other plants and organisms. Be especially careful not to expose people with respiratory problems, asthma, allergies, or heart problems, as well as very old or very young people or pets.

Benefits of synthetic chemical pesticides include their quick action, ease of application, and immediate effectiveness. They are often only a temporary solution, however, and repeated applications may be needed. Some cover a very broad spectrum and kill beneficial as well as harmful insects. If pesticides are used indoors, the air may bear residues long after the application.

Used properly and in conjunction with other preventive and nonchemical methods, pesticides can help combat pests. Remember that technique and timing of application are as important as the pesticide used. Read and follow all label directions. Refer to Chapter 3 for information on using pesticides, Chapter 4 for how to use pesticide label information, and Chapters 5 to 15 for pest management options.

Insect Repellents

Repellents are generally useful against mosquitoes, flies, fleas, and ticks but should be used with care. When needed, apply to pants, cuffs, socks, shirtsleeves, or hat brims, but avoid direct contact with skin.

Kinds of Formulations

Pesticides for home and garden use contain the active ingredient combined or formulated with other ingredients to make them usable. They are available for application with dusters, sprayers, pressurized cans or aerosols, lawn spreaders and seeders, and as baits. The formulation you choose will depend on the equipment you have, the pest you need to manage, the availability of suitable materials, and your preference.

Dusts

Dusts are formulations packaged for use in dusters. They are ready to use and cannot be mixed with water for spraying. The concentration of active ingredient in such pesticides rarely exceeds 5 to 10 percent. Dusts are most effective if applied when the air is still and the foliage is covered with dew or moisture.

Sprays

Several formulations of pesticides are packaged for use as sprays. Some of the more common sprays include wettable powders (WP), flowable formulations (F), emulsifiable concentrates (EC) or emulsions, sprayable oils (S), and oil-base sprays.

A wettable powder contains an active ingredient, a wetting agent, and an inert material. It must be diluted and sprayed as a water suspension. If your sprayer does not have an agitator, the mixture should be shaken periodically to keep the powder from settling out. Do not use a wettable powder as a dust. Such use would be very hazardous because wettable powders are much too strong, usually 40 to 50 percent active ingredient. It is also wasteful and costly. Wettable powders, mixed with water, adhere to plants longer than dusts, but not as well as emulsifiable concentrates.

A flowable formulation contains fine particles of the active ingredient suspended in a flowable liquid or paste. It must be diluted with water. Such formulations resemble wettable powders in their other properties.

An emulsifiable concentrate contains an active ingredient, a solvent, and an emulsifier. Upon dilution with water these ingredients form an emulsion. Apply with a sprayer. Emulsion sprays require less agitation than do suspensions formed by flowables and wettable powders. Caution is stressed because the solvents may cause or contribute to plant injury.

Horticultural spray oils primarily control scales, mites, and aphids. They are recommended as dormant sprays (applied in early spring before buds open). These oils contain an emulsifier. They are mixed with water before spraying. An insecticide, ethion, is sometimes formulated with oil. Oil plus ethion is often more effective for scale insect control than oil alone.

An oil-base spray contains an active ingredient dissolved in a solvent ready for use, and it cannot be mixed with water. The concentration of pesticides is usually low. Oil-base sprays should not be sprayed directly on plants or animals. Thermal foggers use a special oil-insecticide formulation.

Pressurized Cans or Aerosols

Pressurized cans or aerosols are self-contained and require no additional equipment or dilution for use. There are important safety considerations. Regardless of the safety of the active ingredients to humans, certain propellants may be hazardous. Do not leave pressurized cans on a stove or radiator, in direct sunlight, or in the trunk or glove compartment of a car. Temperatures of 120° F or above may cause explosions. Do not puncture cans. Do not use near open flames. Never inhale sprays or discharge an aerosol toward the face of people or animals. To dispose of pressurized cans, exhaust all gas through the release valve and place cans in a trash receptacle.

There are two basic types of pressurized cans or aerosols:

· Space sprays, or true aerosols, dispense a fog or spray of fine droplets that float in the air. They kill flying insects such as flies and mosquitoes.

· Surface or residual sprays dispense large spray droplets that fall from the air rapidly. They form a surface deposit to control crawling insects.

Granules

Granules can be applied by lawn drop spreaders and seeders or from a self-contained shaker package. Fertilizers and some pesticides are formulated in this manner. Granules are much like dusts, except that the particles are larger and more uniform in size.

Fertilizer-pesticide combinations are available as granules or as a fine powder for application with a lawn spreader. They should be used only for the purposes specified on the label. Fertilizer-pesticide combinations are not recommended in this guide.

Baits

Baits contain a food substance to which a poison has been added; they are intended for specific pests. Formulations are available for use inside the home as well as outside. They should be placed so that children and pets cannot reach or eat them. In the house baits should be put in place after children have gone to bed and collected before they get up in the morning. Special bait boxes that can be locked to prevent children and pets from gaining access can be used. Nearly half the accidental poisonings from pesticides happen to children under five years of age who eat baits intended for rats, mice, ants, or roaches.

Multipurpose Mixtures

Many multipurpose (MP) mixtures are on the market. Most are designed for use on plants. Some multipurpose mixtures are formulated especially for a particular crop such as roses or tomatoes. Prepared multipurpose mixtures often eliminate the need for keeping other pesticides on hand and are more likely to be used up in one season; thus long-term storage problems are eliminated. Severe outbreaks of hard-to-manage insects or diseases, however, may require selective pesticide treatment.

When using a multipurpose mixture for plant protection, spray at regular intervals throughout the growing season. Purchase a prepared mixture for a specific plant group or prepare your own mixture as described for tree fruit on p. 62. Prepare only what you will use at one spraying; home-prepared mixtures should not be stored. Use only wettable powder concentrates in preparing multipurpose mixtures. Shake the spray mixture frequently to keep the powder in suspension. Apply with a compressed-air or hand-pump sprayer (slide-pump or other type)

Pest Management Guidelines A Cornell Cooperative Extension Publication	New York Pest Management Guidelines
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