Audubon At Home >

YOU HAVE A CHOICE!
Blank

Despite the prevalence of synthetic pesticides on the shelves of hardware stores and gardening centers, you have many other options for pest control that pose no, little, or much less toxic risk.

Click on any of the following to explore your options:

Whiteflies, a common insect pest. Photo courtesy USDA Cooperative Ext. Slide Series insectimages.org

PHYSICAL METHODS
HEAT & NONTOXIC SUBSTANCES
TRAPS, VISUAL LURES, NONTOXIC BAITS
HORTICULTURAL OIL SPRAYS
INSECTICIDAL SOAPS
BIOLOGICAL CONTROL
MICROBIAL PESTICIDES
BOTANICAL INSECTICIDES

Blank

Blank

Blank

Physical methods

Pull a weed, swat a fly—many times pest control need be no more high-tech than that. Physical control simply means that you are physically removing a pest from a target area or blocking its entry into the area.

Several physical methods can be used to curb infestations of Japanese beetles. Photo courtesy of Doug Stone, Mississippi State University, www.insectimages.org

  • • Pluck bugs by hand and drop in pail of soapy water
  • • Wash plants with a hose
  • • Pull weeds by hand –ideally before they set seed
  • • Prune infested or diseased branches
  • • Vacuum bugs from home or plants
  • • Use landscape paper or mulch to prevent weeds from recolonizing cleared areas
  • • Caulk potential entry points around doors and windows; repair cracks in foundation walls
  • • Remove both ends of a can or plastic cup and place around stems of vegetable plants – forming a collar against cutworms
  • • Encircle plants, pots, or beds with copper flashing to deter snails and slugs
  • • Use row covers to block insects
Blank

Heat & Nontoxic substances

Boiling water can be used as a non-toxic alternative for controlling weeds and ant colonies. Photo by Steven J. Saffier/NAS

  • • Kill weeds in driveway cracks with boiling water or a propane torch
  • • Sprinkle natural grade diatomaceous earth in pest hiding places and entry points
  • • Sprinkle corn gluten meal on turf grass to inhibit root formation during germination of annual weeds such as dandelions and crabgrass
  • • Pour boiling water into ant mounds – do early in morning when colony is closer to surface
  • • To kill weeds over larger areas, cover with black or clear plastic, secure to ground, and leave for 4 to 6 weeks. Resulting elevated temperatures will kill subsurface roots and seeds.
Blank

Traps, Visual Lures, Nontoxic Baits

Beer placed in a shallow pan will help control slug and garden snail populations. Photo by Steven J. Saffier/NAS

  • • Bait slugs with beer or yeast solution (1 tsp yeast in 1 cup water) in saucer placed flush with garden soil surface
  • • Position outdoor lights away from windows, doors, or seating areas to lure insects away from these sites
  • • Yellow sticky cards trap aphids and whiteflies attracted by the color
  • • Sticky fly strips are effective when hung in small enclosed areas; flies like to land on narrow, vertical objects
  • • Lure yellow jackets into narrow-necked bottles or jars containing fruit juice, or meat or fish submerged in water. Commercially made traps are readily available.
Blank

For more information:

Blank

Horticultural oil sprays

Scales on the needle of a Blue Spruce. Photo by Whitney Cranshaw, Colorado State University, insectimages.org

What are they?
Horticultural oil sprays are comprised of certain oils that are mixed with an emulsifying agent to allow them to be diluted with water and applied as a spray for the control of many plant pests including aphids, mites, scale insects, whiteflies, and others. These oil sprays are usually based on highly refined petroleum products, but some effective vegetable oil-based sprays are available.

Two common horticultural oil sprays readily available to home gardeners are now named primarily for the time of their application rather than for characteristics of the oil. Dormant oils are used on woody plants during the dormant season. Summer or foliar oils can be applied during the growing season when foliage is present.

Advantages:
Horticultural oil sprays, especially those based on vegetable oils, pose few risks to human health and non-target species. Oil sprays quickly dissipate through evaporation, leaving little or no residue. There is no evidence that their use can lead to insect resistance.

Disadvantages:
Primary disadvantage to horticultural oils is their potential to cause plant injury in some situations. Some plants are more sensitive than others and taking recommended precautions will minimize the risks to plant safety. See the reference below for discussion of recommended precautions. Petroleum-based oils may cause skin and eye irritation, and may leave behind more residues than vegetable-based oils.

Blank

For more information:

  • • For excellent discussion of the horticultural oils - their varieties and uses, see:

    Cranshaw, W.S. and B. Baxendale.     Insect Control: Horticultural Oils. Colorado State University Cooperative Extension. Online. Internet. Last updated June 06, 2001.
Blank

Insecticidal soaps

Mealybugs such as these can be treated with insecticidal soaps. Photo by Sally Simons, insectimages.org

What are they?
Soaps are made from the salts of fatty acids—which are the principal components of the fats and oils found in animals and plants. Insecticidal soaps are made with fatty acids that have insecticidal properties. The soap itself is the active ingredient; it is not a soap to which insecticides have been added. Oleic acid, a fatty acid found in high quantities in olive oil, is especially effective and commonly used in insecticidal soaps.

Insecticidal soaps are most effective against many soft-bodied pests such as aphids, mites, whiteflies, thrips, caterpillars, mealybugs, etc. They are less effective against pests that have a heavier cuticle such as beetles and grasshoppers. Soaps must come in contact with the pest to be effective, and are active only when wet.

Advantages:
Soap residues degrade rapidly. They are no more toxic than common household soaps and detergents.

Disadvantages:
Insecticidal soaps can kill soft-bodied stages of beneficial insects and so care must be taken to apply to pest infestations only. Soap is effective only when wet so repeated applications are usually necessary. Some soaps may burn the foliage of sensitive plants.

Blank

For more information:

Blank

Biological control

Cocoons of the parasitic Braconid wasp mean imminent doom for the host, a tobacco hornworm. Photo courtesy Clemson University – USDA Cooperative Ext. Slide Series, www.insectimages.org

What is it?
Biological control is the use of organisms that are the natural enemies of pests to reduce pest populations. Biological control, as opposed to the natural control of pests by ongoing environmental and ecological forces, typically involves an active human role.

Biological control can be effective in managing insect and weed pests, and plant diseases. Beneficial natural enemies may be predators (e.g., lacewings, lady beetles), parasitoids (e.g., parasitic wasps), or pathogens (e.g., nematodes; single-celled pathogens are discussed under “microbial pesticides” below).

Natural pest enemies are present in every healthy ecosystem.
Conservation of existing populations is the most efficient way to implement biological control and to maximize its effectiveness.

Protect and encourage the presence of beneficial species in your lawn and garden.
Learn what different beneficial species look like. Many pesticides kill beneficial organisms as well as pests so use pesticides minimally and selectively. Provide shelter, overwintering sites, and alternative food sources for those beneficial species you want to encourage. If necessary, natural populations of natural pest enemies can be augmented by purchasing and releasing additional individuals.

Advantages:
Biological control draws upon and encourages natural processes. It can be an effective pest management tool for homeowners as well as in agriculture. By conserving and encouraging organisms that selectively target identified pests, there is no risk to non-target species.

Disadvantages:
Effective practice of biological control requires knowledge of the life cycle and biology of both beneficial and pest species.

Blank

For more information:

Blank

Microbial pesticides

What are they?
Microbial pesticides are comprised of certain one-celled organisms (including types of bacteria, fungi, viruses, and protozoa) that have the capability to kill specific pests. They are formulated into dusts, sprays, and granules and are applied in the same way as conventional pesticides. They are considered a type of "biopesticide" by the EPA and are regulated by the EPA.

The most widely used microbial pesticides in the U.S. are strains of the bacterium, Bacillus thuringiensis or Bt. Each strain produces a different toxin that kills different pest species or sets of species. Some Bt’s are toxic to a wide array of butterfly and moth larvae, others kill the larvae of mosquitoes and black flies, and still others target other pests.

Another commonly used microbial pesticide is milky spore disease. Comprised of the bacteria Bacillus popilliae and Bacillus lentimorbus, it is used to control Japanese Beetle grubs.

Advantages:
Many are essentially nontoxic to humans, wildlife, and other organisms not closely related to target pest. Often effective in small quantities.

Disadvantages:
Proper timing and application procedures must often be followed carefully for effective use.

Blank

For more information:

  • • Visit the EPA website for Biopesticides for detailed information, including fact sheets and available products, for all registered microbial pesticides

    Note: At this website, microbial pesticides are grouped according to the microbe involved, bacterium vs. fungus vs. virus, etc. Classes of non-microbial biopesticides (e.g., pheromones, growth regulators, etc.) are also listed.
  • • For assistance in locating sources of microbial pesticides, see:

    Johnson, D. 1998.     Vendors of Microbial and Botanical Insecticides and Insect Monitoring Devices. University of Kentucky College of Agriculture Cooperative Extension Service. 8 pp.
Blank

Botanical Insecticides

Botanical insecticide – photo by Steven J. Saffier/NAS

What are they?
Botanical insecticides are naturally occurring plant extracts and compounds that have insecticidal properties. They can be found in various forms: (1) dusts or powders ground from dried seeds, flowers, roots, bark, etc., (2) concentrated extracts, oils, or resins, and (3) purified and isolated compounds. Although botanical insecticides are naturally occurring, it is important to realize that they are not necessarily nontoxic or safer than synthetic chemical pesticides. They are pesticides and are regulated as such by the EPA. They include some of the fastest-acting, most deadly toxins known.

Sabadilla, Pyrethrum, and Neem are among the least toxic to humans of the botanical insecticides. Be aware though that sabadilla is very toxic to honey bees and pyrethrum is very toxic to cold-blooded animals.

Advantages:
Most botanical insecticides degrade rapidly in the environment. Persistent residues are much less likely than with synthetic pesticides.

Disadvantages:
Botanical pesticides vary greatly in their toxicity to humans as well as to non-target organisms. Use all precautions recommended when using synthetic pesticides.

Blank

For more information: