Editor’s Note: The Canadian Food Inspection Agency (CFIA) has granted ISO 17065 accredited evaluation programs, including some Certifying Bodies (CBs) and other organizations, such as the non-profit Organic Materials Review Institute (OMRI), the ability to verify that production inputs meet Canada Organic Standards (COS) requirements. OMRI has partnered with The Canadian Organic Grower Magazine to provide a series of articles to help explain certain nuances and developments related to permitted inputs. CFIA-accredited CBs are still ultimately responsible to ensure client compliance with the Permitted Substances Lists (PSL); operations should always contact CBs before applying any material to certified organic or transitional land. Another good resource to consult for information regarding inputs permitted by the COS is organicinputs.ca.
Finding an organic solution to pest and disease control is a challenge faced by all organic growers. Pests can quickly destroy an entire crop, from Botrytis (grey mould) in strawberries to flea beetles in broccoli. The tenets of organic agriculture call for using cultural and mechanical practices, such as varietal selection, sound rotations and mulching, as primary methods to enhance crop health and minimize losses. But even traditionally resistant varieties in a well-balanced system can still be susceptible to pests. When carefully planned rotations, proper sanitation and other preventative practices prove insufficient, what is the next step in controlling pests in organic production?
Although the term ‘pesticide’ tends to evoke concerns of toxic chemicals and persistent residues, many naturally-derived substances such neem, clove and citrus oils, comply with organic practices and standards. Only chemicals that have been identified by Health Canada’s Pest Management Regulatory Agency (PMRA) as being of minimal toxicological concern, or that have otherwise been determined to not have adverse health or environmental impacts, may be used in organic production. Pesticides don’t even have to be chemicals. If you’ve introduced ladybugs or praying mantis populations in your garden, you’ve employed a biological control to mitigate pest activity. Along the same principle but on a smaller scale, many microbial cultures also provide biological control, either through direct infection of the target organism or by indirect competition for resources.
Pests can quickly destroy an entire crop, from Botrytis (grey mould) in strawberries to flea beetles in broccoli. The tenets of organic agriculture call for using cultural and mechanical practices, such as varietal selection, sound rotations and mulching, as primary methods to enhance crop health and minimize losses. But even traditionally resistant varieties in a well-balanced system can still be susceptible to pests. When carefully planned rotations, proper sanitation and other preventative practices prove insufficient, what is the next step in controlling pests in organic production?
Diatomaceous Earth (DE) is a naturally occurring pest control substance, produced from marine sediments of fossilized diatoms, a form of microscopic algae. DE feels like a soft powder to the human hand, but at the microscopic level, the intricate cell walls of diatoms have a very abrasive structure. With extremely sharp edges and highly absorptive qualities, DE works by damaging and dehydrating the bodies of insects and other target pests . However, depending on the manufacturing process, DE may or may not be compliant with organic standards. DE products heated at high temperatures during manufacturing, which alters the microscopic structure, are not permitted for use as a crop production aid by the COS. Unfortunately, it is not easy to tell which products on the market have been heated and which have not.
Other pest control substances available to organic growers are described in Table 4.3 of CAN/CGSB-32.311 Permitted Substances Lists (PSL). Dormant and summer oils are listed there, as well as pheromones used in traps or dispensers, insecticidal soaps, and other chemicals such as hydrogen peroxide and ferric phosphate. Hydrogen peroxide is an effective fungicide; it is not permitted as a crop production aid in maple syrup production, however. Ferric phosphate can be used to control those voracious slugs, as long as it does not come in direct contact with crops or cause contamination via runoff of nearby waterways.
Organic farmers must exercise caution when sourcing a pesticide for use in an organic system. Unfortunately, product labels rarely disclose the substances used to extract these pest control substances from the plant and/or formulate the final product, leaving the farmer uncertain as to what other chemicals or materials they might unintentionally apply to crops. In fact, most pesticides include ingredients (deemed “inactive” that do not appear on the product label which often account for 90% or more of the formulation. These can be harmless ingredients, such as flour [or] sugar that help disperse the pesticide, as well as synthetic chemicals used to bind, stabilize or distribute the active ingredient. Advertised use instructions can also be misleading, with some product labels describing uses that are not compliant with organic standards. For instance, materials compliant for use in organic production for pest control around the exterior of a barn may not be allowed for pest control in the field, and many pesticides can only be used to treat specific target pests under specific circumstances.
Some CBs publish lists of approved inputs under the PSL. The OMRI Canada Products List© of brand name products verified as being compliant with the Canadian Organic Standard is also now available. The OMRI List includes product and use-specific restrictions, including permitted extraction methods and manufacturing processes. Users of this list should remember, however, to always read the use entries and restrictions carefully, and to contact their CBs before applying any material to certified organic or transitional land.