How to Reduce Insecticide Use in Your Landscape
Ask a Specialist: Options for Reduced Insecticide Use in the Landscape
By: Taun Beddes, USU Extension horticulturist, email@example.com
Best management practices can be used to reduce or eliminate insecticide use in the home landscape. Some include irrigating properly, using adapted plants and accepting low pest damage levels.
There are times when insecticide use may be justified, however. If you are not sure, contact your local USU Extension office or experienced garden center personnel with questions. When pesticide use is recommended, many less toxic, reduced-risk options exist that have shorter pre-harvest intervals (the wait time required from spraying until food crops can be harvested) when used correctly. The following list is not comprehensive but offers common options. Be sure to always follow the label.
* Bacillus thuringiensis (Bt): Bt is a naturally occurring gut bacteria found in many insect species. Some strains are toxic to certain insects because they form crystal-like compounds in insect gut-tracts that inhibit feeding. Products with Bt are especially effective against pest caterpillars. Alternative strains that control other insects such as mosquitoes, flies and beetles are available. Thuricide is a common brand.
* Spinosad: Derived from a bacteria found naturally occurring in the Caribbean, spinosad is effective against many insect pests. Of the reduced risk options, it is probably the most effective against many fruit pests including the western cherry fruit fly and coddling moth. Fertilome Borer, Bagworm, Tent Caterpillar and Leaf Miner Spray or Captain Jack’s Deadbug Brew are available from many retailers.
* Azadirachtin or Neem: The active ingredient is derived from pressed fruit of the neem tree in India. It suppresses insect feeding, smothers and repels many insects and also has fungicidal properties. Neem is often blended with other botanical insecticides such as pyrethrins. Look for Fertilime Triple Action, Fertilome Fruit Tree Spray, Fertilome Neem-Py, and Bayer Neem Oil Concentrate.
* Horticultural Oil: Oils can be useful for smothering dormant and active piercing-sucking insects such as aphids and scales. Oils are often applied in late winter as a preventative. Summer weight concentrations can also be mixed. Most oils must be applied directly to the insect to be effective.
* Horticultural Soap: Horticultural soaps are specifically formulated for landscape insect control as compared to products such as dish soap. They can be effective but must be applied directly to the insect, having no residual properties. Safer is a common brand. USU Extension recommends horticultural soap over homebrew soap mixes since exact mixing instructions are included on the label.
* Canola Oil: See horticultural oil.
* Pyrethrins: These are derived from a species of chrysanthemum and control multiple insect pests. They are often included in reduced-risk fruit tree sprays and blended with other active ingredients. Bayer Natria Insect, Disease and Mite Control and Fertilome Neem-Py contain pyrethrins.
* Diatomaceous Earth: Diatomaceous Earth does not act as an internal poison. Instead, it is a powder that consists of fossilized diatoms. It feels somewhat like talcum powder. However, microscopically it has the texture of sharp, broken glass. It is used to control soft-bodied crawling insects such as caterpillars. The dust can also get into the joints of hard-bodied insects and offer control through rubbing action.
* Iron Phosphate: This is an alternative control for slugs and snails and is not toxic to pets. Many options are available, but good choices are Sluggo or Bonide Slug Magic.
Direct column topics to Julene Reese, Utah State University Extension writer, Logan, Utah, 84322-4900, 435-797-0810; firstname.lastname@example.org.