Effective and Safe Alternatives to Insecticides

Photo © Gary Tyson

After all the work of prepping, planting, and preening your gardens, the last thing you want to see are insects eating it to the ground. When the beetles, larvae, and aphids start getting out of hand, it may be tempting to grab the can of bug spray and make the job of eradicating the pest a simple matter. But is it really that simple? If we take a look at the real and persistent risks of insecticides and compare to the effectiveness of safer alternatives, we find the equation is not as straightforward as many of the marketing labels would have you believe.


Photo © Oregon Department of Agriculture

Insecticide is poison. It is designed to kill. The EPA sets limits and regulations on all pesticides based on toxicity levels and risk to the user. When used correctly insecticides can benefit society by improving food growth, storage, and transport capabilitiesopen_in_newopen_in_new, by acting as a tool for environmental conservation and managementopen_in_new, and even by mitigating health and safety concerns that arise from heavy pest infestationsopen_in_new. Most insecticides require application by certified licensed applicators that follow rigorous methods of control and reporting. Licenses must be renewed and updated annually to keep certified applicators informed and conscientious. The rest of us must carefully read and follow directions on the label precisely. There are many cases of ambitious homeowners misusing insecticides on their property resulting in harm or death to family members, neighbors, and/or pets. Something as simple as watering the lawn after an application of insecticide can create toxic fumes that can quickly kill anything or anyone that inhales it.


Photo © Mike Licht

A big problem with insecticides may be that we are just too quick to reach for them. Many effective insecticides are quite specific–not only to particular species, but also to specific stages in the bug’s development. Using the wrong chemical, on the wrong bug, or at the wrong time, introduces toxic hazards into your living areas without solving your problem. Matching the correct active ingredient to the problem and applying the insecticide correctly, including proper placement, timing, and amount, are essential for both safety and efficacy. It is useless and dangerous, for example, to spray adult bugs that have already laid their eggs and will simply die naturally within a few days–not an uncommon trait among pupating insects. Timing failures like this can introduce risk with no benefit.


Photo © jetsandzeppelins

On the other hand, broad-spectrum insecticides like organophosphates, carbamates, pyrethroids, and neonicotinoids will work on many types of insects at various stages of development. This also means they may kill valued and beneficial insects too, including bees, butterflies, and caterpillars. Some evidence suggests that wildflowers, commonly left along agricultural margins, can become exposed to levels of neonictinoids at levels found on crops. Blue butterfly (Polyommatus icarus) nectaring on these neonictinoid-covered wildflowers can exhibit developmental issues and early mortality.open_in_new Organophosphates are systemic insecticides that can persist for a long time, sometimes even contaminating pollen and nectar long after the insecticide was applied.open_in_new Many are highly toxic and improper use can harm humans and pets around the home, or birds, fish, and other nearby wildlife when spray drift or runoff enter natural habitatsopen_in_newopen_in_new. Some, like the popular neonicotiniod, imidacloprid, and a common organophosphate, chlorpyrifos, can even impair a bird’s migratory abilities, affecting body mass and orientationopen_in_new, both of which are important for surviving long migrations.


Photo © Cornell Lab of Ornithology

Increasing resistance to insecticides is another concern with overuse. Sometimes, due to genetic or behavioral differences, individuals of an insect population may not be affected by an insecticide. Those unaffected may go on to reproduce successfully, leading to breeding resistance in their offspringopen_in_new. Building resistance like this is similar to how bacteria develop antibiotic resistance. Both lead to more applications of stronger/different poisons in order to maintain the same level of effectiveness. For the home and garden, there is a better way.


Photo © John Flannery

Natural environments, including botanic and vegetable gardens, are generally insect hotspots and that is a good thing. This diversity of organisms will likely include some that eat plants but will also include many predator species that happily consume those plant eating bugs. This balance is nothing new in the natural world and you can incorporate this eco-logical concept into your gardens and landscaping practices by growing native plants and eliminating insecticide use. There are many ways to encourage beneficial insects in your vegetable or botanical gardens to create this balanced system of predators and prey, leaving only minimal and, dare we say, acceptable damage to your prize plantings (most plants are tolerant of some baseline level of herbivory by insectsopen_in_new and the product, the fruits and vegetables we eat, may even provide better nutrients after experiencing some pressure from the insect damageopen_in_new).


Photo © JR P

Including a range of native plants in your landscaping can be incredibly beautiful as well as resilient. Locally native plants have developed their own chemical and seasonal defenses for many of the local insects. For millennia plants have needed to defend themselves against insect herbivory and can deter bugs through secondary metabolites that are toxic or unappetizing. Others may just be seasonally unavailable during times when certain pests are abundant and hungry. Native plants may also be more likely to attract a host of predators, like birds, bats, and wasps, that will eat bugs. A diversity of native plants can be key to providing necessary habitat for a diversity of insects and other wildlife that keep pest populations in check.


Photo © CIAT

Integrated Pest Management (IPM) is another, more proactive, alternative. IPM is an effective, whole-system approach for controlling unwanted herbivores in growing environments from greenhouses to gardens to larger green spaces. It is an environmentally sensitive method to pest management that relies on current, comprehensive information on the life cycles of pests and their interaction with the environment to provide efficient strategies and actions, keeping pest populations and their damage at acceptable levels. IPM starts with proper identification of the insect to determine the appropriate measures, if any, that are needed to control damage. Control methods begin with the least pervasive actions, like including native plants and encouraging beneficial insects, as mentioned above. Mechanical or technical solutions should be used next and specific, constrained use of insecticides saved as a last resort.

Along with the above actions, here are some examples of IPM techniques you can use around the home and garden to eliminate insecticide use and effectively control pests.

The Nature Conservancy’s Nature Works Everywhere gardens program utilizes project based learning techniques for elementary and middle school children to teach them the importance of nature and it’s impacts on future generations. Students at Curtis Bay

Photo © Photo © The Nature Conservancy (Jeffrey MacMillan)

-Be watchful. Inspect the gardens regularly to be aware of any new pests that may emerge and act before the damage is too great. You can remove caterpillars and eggs by hand or with a damp cloth and knock beetles into a bucket of soapy water. A handheld vacuum can be used to collect fast moving cucumber beetles. Do your checks at various times of the day as some bugs come out in the morning while others may wait for the warmer afternoons to eat. Recheck any damage you find a couple of times to determine if it is going to continue. Sometimes insect predators will naturally take care of the problem before you can even get to it.


Photo © Rhiannon Crain

-Identify new insects. Determine whether they are harmful, beneficial, or benign to the vegetation. It is important to remember, when making choices about insecticide use, that insects are an important food source for other wildlife. Many species of songbirds rely almost entirely on insects to meet the bulk of their dietary needs. Most bats in North America, too, depend on insects to sustain them throughout the year.


Access the experience and expertise of the community! Do you have a pest problem you can’t identify? Have you found a safe and effective way to manage mites? Post questions, pictures, or solutions you’ve discovered in the Habitat Network Forum.


Photo © Monica Hargraves

-Consider the life cycles. Both the pest and the plant generally have predictable phases of growth and development. For example, bugs like these sawfly larvae will cause damage to leaves in the fall but are not necessarily harmful to the deciduous dogwood shrub so, although they may appear aggressive, no action is needed.


Photo © michel bish

-Grow Healthy Plants. Improve the growing conditions in the garden. Use compost and other soil improvements, efficient irrigation, and proper sun and spacing to help plants help themselves. Productive plants can often outgrow regular insect damage. Rotate garden crops annually and clean up decaying vegetation to keep pest populations and soil pathogens from increasing year after year.


Photo © VitaminGreen

Use companion plantings. Companion plantings are crops, herbs, flowers, or other plants placed next to, or near one another, in a garden to benefit each other in some way. Benefits include structural support and maximizing growth, as well as discouraging pests, and include trap plants that will lure common pests away from garden crops. For example, the rows of radishes and carrots above may benefit each other by repelling flies above ground and discouraging grubs below.

Pumpkin/Corn Patch

Insecticides alternative

Photo © Distant Hill Gardens

Use row covers. Barriers are effective ways to keep many types of pest away from vegetation. They may only be necessary while plants are young or while a threat persists. Again, being aware of the bug’s life cycle can help you determine when it is important to cover and protect and when to remove as the plants need it. Be sure, though, not to have crops covered when they are pollinating.


Photo © CameliaTWU

-Diatomaceous Earth. A powder-like dust made from the silicate skeletons of tiny ocean-dwelling creatures called Diatoms. These skeletons are mined from dry land where prehistoric seas once occurred. DE acts like broken glass to inhibit movement and kill pests by cutting into their waxy cuticle. It can either be added to the soil for grubs, applied to the soil surface for slugs and snails, or sprinkled on the foliage for mites, aphids, and larvae.


Photo © Keith Rowley

-Horticultural Oils and Insecticidal Soaps. Derived from extracts of vegetable or crude oil and fatty acids, these two techniques are non-toxic to people and animals but are lethal to target insects. Oils clog pores that insects use to breath and soaps are toxic once ingested or absorbed. They work well with other IPM controls, dissipate quickly without residue, and are easy for the home gardener to apply.


Insecticides alternative

Photo © SteveR-

-Make a beer trap. Slugs can be the most elusive and damaging pests to many garden plants. They hide beneath the mulch or just under the soil at the base of the plants until the cool, moist evenings and mornings when they climb up and begin devouring the foliage and blossoms. You can pour some inexpensive beer into a shallow container and place it on the ground among the plants–the slugs are drawn into it and will quickly perish. To hide the trap, bury an open, full beer bottle with just the top inch sticking out of the soil. Some traps are even commercially available.


Photo © Xtream_i

-Put your foot down. Sometimes a good-old-fashioned squashing is the easiest alternative. A well-placed shoe, a rolled up newspaper, or just a quick swat of the hand, can quickly remove the pests from your garden. If you are committed to the goal of reducing pesticides, being diligent and determined, and producing vibrant, lush, and productive gardens can give you the knowledge and confidence to be a powerful advocate in your neighborhood.


Photo © meaduva

Regardless of the method, or combination of methods, you choose to use, keeping the pressure on the pests in your landscape will help tip the balance in your favor– allowing your plants to outgrow the damage while maintaining a safer environment for you, your family, your pets, the neighbors, and essentially, because insecticides can persist in the environment and be unknowingly translocated into others’ living spacesopen_in_new, your community.



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