Thursday, February 6, 2014

It's not easy finding green

Occasionally I get a request from someone seeking a listing of green insecticides. Of course this is a difficult question to answer without knowing exactly what someone means by a "green insecticide".  Green means different things to different people.  To some it means something natural or organic, overlooking the fact that many highly toxic compounds are found in nature. Others might not restrict a list of acceptable insecticides to only products that occur in nature, but might include some man-modified compounds if they were sufficiently easy on the environment.

Personally I prefer the concept of low impact pesticides. I define "low impact" to include any pesticides (man-made or natural) that pose low risk to humans and to beneficial organisms (including wildlife, pets and beneficial insects).  Using this definition, it's not too hard to find products that fit the description from both the organic and the synthetic side of things.

Examples of man-modified or produced insecticides that meet the low impact criteria include soaps and oils, insect growth regulators, microbial-based products, and reduced risk pesticides identified by the U.S. EPA. If the properties of such products were understood properly, most of these insecticides would be acceptable to most people.

So are there any lists of low-impact, or green pesticides?  A few resources come to mind.  First, Texas has a loose definition of green pesticides in its Green Category products that schools are encouraged to use.  For a summary of these pesticides, see

Another resource is the U.S. EPA list of reduced risk products.  This list is tucked away online in an obscure, online EPA cubbyhole on the Conventional Reduced Risk Pesticide Program.  While this is a regulatory concept and not intended as a list of the lowest risk pesticides, it does list some interesting insecticides that might not be otherwise noted by people seeking lower impact alternatives to more conventional products.  For a list of RR pesticides, click here.

One of the frequently cited sources of "acceptable" pesticides in green circles is the City of San Francisco's Reduced Risk Pesticide list.  The list is designed around professional products that can be used by city employees, and is not intended for consumer reference (click here for consumer low-impact options).  It is, however one of the few sites that has some scientific review and is continually updated with new products--a lot of work.  Municipalities and LEED building architects frequently refer to Tier III pesticides on this site as the standard for acceptable pesticides.

Lastly, the EPA's list of Minimum Risk (or 25b) compounds that are considered exempt from standard label requirements bears mention. This list contains ingredients that are "generally regarded as safe" by the EPA.  Unfortunately, being safe doesn't always make for an effective pesticide; but manufacturers continue to roll out new products with these ingredients because of the economic advantages of not having to register with the EPA.

None of these lists are perfect and all are highly arbitrary in some respects. They all have their uses and limitations.  All of them leave out some very useful pesticides that can solve otherwise intractable pest problems at reasonable risk to the environment. Some "green pesticides" may be very green, but not make very good pesticides--a common problem.  For these reasons, my advice would be to not commit oneself to a course of saying that "only these (select, green, organic, etc.) pesticides will be used" in our city, or our school, or our place of business.

Pesticides are power tools.  Like any power tool, along with their advantages, they have potential hazards. That doesn't mean we shouldn't use them, but that we should choose them and use them with caution.  If you're committed to using pesticides from a green list for your school, city or business, give yourself options. The Texas school regulations and the San Francisco program have both been relatively successful.  But they both allow for exemptions or exceptions for using pesticides not on the preferred lists.  The worst mistake any green pest control program can make is to limit itself so that it cannot effectively or economically respond to all pest problems. That's the quickest way to discredit any green program as impractical.

As Kermit the Frog would tell you, "it's hard to be green".  It's also hard to find the perfect green list of pesticides that will cover all pest problems. Keep this in mind, and these lists might actually help you.

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