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How Landscaping Can Support Declining Bee Populations

July 31, 2013

from beebiology.ucdavis.edu

Research and observation increasingly suggest that pesticides are harming bee populations on a frightening scale. The magnitude of recent bee deaths has prompted a re-evaluation of national and local uses of pesticides.

One field under the microscope is landscaping. Landscapers and their customers need to confront the question of whether the benefits of using pesticides outweigh the potential harm done to valuable pollinators. By continuing current pesticide practices we face the apocalyptic cost of losing pollinators that play a crucial role in supporting human life.

Bees Are Dying. Why?

Colony Collapse Disorder (CCD) has wiped out an estimated 10 million beehives, worth $2 billion, over the past six years. Bees (both honey bees and bumblebees) and other insects are vital for global food production. Together they pollinate about three-quarters of all world food crops.

The frightening declines in global bee populations have been associated with many environmental factors: industrialization, air pollution, parasites, and mono-crop planting schemes. But the factor most closely connected with bee disappearance is pesticide use. A number of recent studies point to pesticide exposures as a direct, or indirect, cause of CCD.

Although the recent deaths of over 50,000 bees in Wilsonville, OR, doesn’t exactly qualify as CCD – as the deaths look more like outright poisoning – they were likely caused by profligate spraying of dinotefuran (or Safari), a type of neonicotinoid insecticide used to control sap-feeding aphids.

Most research has focused on agricultural pesticides, but a growing body of research suggests that neonicotinoids used by homeowners and landscapers could play a large role in bee die offs.

What Can Be Done?

Preserving bee populations requires promoting beneficial pollinator habitats. Farmers, landscapers, and gardeners can promote diverse vegetation that supports insect diversity and resilience. They can also use non-toxic methods of pest and weed control.

Programs like the EcoBiz Certification for Landscape Professionals* helps participants address pest problems in ecologically sensitive ways. In guiding the sustainable practices of landscaping businesses, EcoBiz strives to promote practices of “Integrated Pest Management (IPM).” IPM is a systematic approach to managing pests that focuses on long-term prevention of pests by accounting for risks to human health and the environment.

Before considering pesticides, according to IPM practice, landscapers should apply alternative pest-management strategies. For example, selecting plants that are well-adapted to local conditions can cultivate natural pest controls that are both effective and aesthetically pleasing. Such a proactive approach to landscape design reduces the need for applying any chemicals.

According to IPM guidelines, pesticides are used only as a last resort after monitoring shows they are needed to remove a targeted organism. If landscapers truly need to use an insecticide, chemicals should be applied according to label guidelines. The landscaping company responsible for poisoning so many thousands of bees in Wilsonville ignored specific spraying guidelines when they chose to spray the foliage of blooming linden trees.

In some areas, businesses no longer have a choice about whether or not to use some neonicotinoids. The weight of evidence connecting bee die offs to some pesticide exposures has prompted international and local restrictions. For example, the European Union recently passed a two-year ban on three types of neonicotinoid insecticides, including Safari. And following the Wilsonville bee disaster, the Oregon Department of Agriculture opted to restrict the use of 18 pesticide products containing the active ingredient dinotefuran.

The Path Ahead

Minimizing or eliminating harmful pesticide use will not be easy. Neonicotinoids are still widely available to the agricultural community, landscapers, and gardeners alike. They remain one of the most widely used families of insecticides in the world, sprayed on virtually all U.S. crops of corn, soybeans, and wheat. Part of the popularity of these pesticides may stem from their reputation as being less acutely toxic than many other pesticides on the market. For example, many neonicotinoids are labeled as “Toxicity Level 3: CAUTION” rather than the more acutely toxic “Toxicity Level 1: DANGER.”

Neonicotinoids may be one of the most common pesticides, but aren’t the only kind ravaging bee populations. A recent PLOS study suggests that honeybees are exposed to a cocktail of pesticides and fungicides that weakens their immune system to the lethal gut parasite Nosema ceranae. Another recent study, in the Journal of Environmental Toxicology and Chemistry, chronicles harmful physiological effects of other types of widely used pesticides.

from beebiology.ucdavis.edu

As a society, we face landscaping and agricultural decisions about how to best deal with local pests, and how to use pesticides in a precautionary manner. By promoting IPM principles, EcoBiz supports a precautionary and reserved approach to any pesticide use. The organization also constantly re-evaluates standards to promote continuous improvement in ecologically sensitive standards.

Does following IPM principles sufficiently protect our environment from harmful pesticides? Are additional landscaping standards needed? Some environmental groups are pushing for stricter, or less vague, limitations on insecticide uses. The Xerces Society for Invertebrate Conservation, for example, has called for a ban on using neonicotinoids and other insecticides for cosmetic purposes. Such a ban would have prevented the Wilsonville spraying, a spraying justified by the cosmetic desire to eliminate aphids that drop a sticky substance on parked cars.

We need to ask ourselves: what values are we applying to landscaping decisions? Are cosmetic landscaping preferences worth the harm done to surrounding organisms, which, in the case of bees, not only beautify our environment but also may be necessary to human life?


Resources / Further Reading:


– By Cyrus Philbrick, Communications Manager

& Mitchell Frister, EcoBiz Associate

* EcoBiz is a third-party verified certification for Landscaping and Automotive businesses in Oregon. EcoBiz participants meet the highest standards to help reduce and prevent water, air, and hazardous waste pollution. For more information, email mfrister@pprc.org or call 503-348-6219

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