Pest Management Regulatory Agency
26 July 2013
ISSN: 1925-0886 (PDF version)
Catalogue number: H113-9/2013-17E-PDF (PDF version)
Summary
Health Canada's Pest Management Regulatory Agency (PMRA), under the authority of the
Pest Control Products Act and
Regulations, is proposing full registration for the sale and use of Corn Gluten Technical and Wilson Garden Weeder with Corn Gluten Meal, containing the technical grade active ingredient corn gluten meal, which is intended for pre-emergent inhibition of weed seed germination in flower, vegetable, and fruit gardens.
An evaluation of available scientific information found that, under the approved conditions of use, the product has value and does not present an unacceptable risk to human health or the environment.
This summary describes the key points of the evaluation, while the Science Evaluation of Proposed Registration Decision PRD2013-17, Corn Gluten Meal provides detailed technical information on the human health, environmental and value assessments of Corn Gluten Technical and Wilson Garden Weeder with Corn Gluten Meal.
The key objective of the Pest Control Products Act is to prevent unacceptable risks to people and the environment from the use of pest control products. Health or environmental risk is considered acceptable if there is reasonable certainty that no harm to human health, future generations or the environment will result from use or exposure to the product under its proposed conditions of registration. The Act also requires that products have value when used according to the label directions. Conditions of registration may include special precautionary measures on the product label to further reduce risk.
To reach its decisions, the PMRA applies modern, rigorous risk-assessment methods and policies. These methods consider the unique characteristics of sensitive subpopulations in humans (for example, children) as well as organisms in the environment (for example, those most sensitive to environmental contaminants). These methods and policies also consider the nature of the effects observed and the uncertainties when predicting the impact of pesticides. For more information please refer to the following:
Before making a final registration decision on corn gluten meal, the PMRA will consider all comments received from the public in response to Proposed Registration Decision PRD2013-17, Corn Gluten Meal. The PMRA will then publish a Registration Decision on corn gluten meal, which will include the decision, the reasons for it, a summary of comments received on the proposed final registration decision and the PMRA's response to these comments.
For more details on the information presented in this summary, please refer to the Science Evaluation of Proposed Registration Decision PRD2013-17, Corn Gluten Meal.
Corn gluten meal is the active ingredient of Wilson Garden Weeder with Corn Gluten Meal, which is intended for pre-emergent inhibition of weed seed germination in flower, vegetable, and fruit gardens. Wilson Garden Weeder with Corn Gluten Meal is for domestic use only.
The mode of action of corn gluten meal is to prevent normal development of plant roots by releasing organic dipeptides into soil and inhibiting root formation of germinating seeds. Corn gluten meal does not prevent seed germination or affect root systems of established plants but rather causes seedlings with less than normal root systems to succumb to dehydration when exposed to drought stress.
Corn gluten meal is unlikely to affect human health when used according to label directions.
Exposure to corn gluten mealmay occur when applying the end-use product or when people enter a freshly treated site. When assessing health risks, two key factors are considered:
The dose levels used to assess risks are established to protect the most sensitive human population (for example, children and nursing mothers). Only uses for which the exposure is well below levels that cause no effects in animal testing are considered acceptable for registration.
The technical grade active ingredient corn gluten meal is expected to be of low acute toxicity via the oral, dermal and pulmonary routes, minimally irritating to the skin, mildly irritating to the eyes, and a potential sensitizer. Therefore, precautionary statements alerting users to the eye irritation and sensitization potential of corn gluten meal are required on the labels for Corn Gluten Technical and the end-use product Wilson Garden Weeder with Corn Gluten Meal.
Based on the information available on corn gluten meal, exposure to humans from domestic use of Wilson Garden Weeder with Corn Gluten Meal is not expected to be of concern due to the low toxicity of corn gluten meal and precautionary statements present on the end-use product label that are aimed at mitigating exposure.Dietary risks from corn gluten meal on food and water are not of concern.
Wilson Garden Weeder with Corn Gluten Meal is proposed for use on domestic vegetable, fruit, and ornamental gardens as a pre-emergent herbicide to inhibit seed growth, and the proposed use is not expected to raise any dietary concern.
No risk due to exposure from drinking water is anticipated as corn gluten meal, by its organic nature, is expected to be degraded in the environment.
Risks are not of concern when corn gluten meal is used according to label directions, which include precautionary statements.
Wilson Garden Weeder with Corn Gluten Meal is to be applied directly from the packaged container. Residential exposure to individuals applying the end-use product is not expected to result in unacceptable risk when the product is used according to label directions. Precautionary statements on the label of the end-use product are considered adequate to protect individuals from residential exposure.
Since the end-use product is granular in form and is to be applied directly from the packaged container, bystander exposure is expected to be negligible.
Precautionary statements on the label of Wilson Garden Weeder with Corn Gluten Meal are considered adequate to protect individuals, children and pets from domestic use of this product.
Corn gluten meal is not expected to pose significant environmental risk when used under the proposed use pattern.
Corn gluten meal is derived from a naturally-occurring substance and is not expected to be persistent in the environment. It has a non-toxic mode of action and a long history of use as an animal food commodity, fertilizer and more recently as a pre-emergent herbicide in turf. Given the limited exposure expected from residential garden use, the risk to non-target organisms from corn gluten meal in the end-use product, Wilson Garden Weeder with Corn Gluten Meal is expected to be negligible.
Wilson Garden Weeder with Corn Gluten Meal, as a pre-emergent treatment in flower, vegetable, and fruit gardens, provides inhibition of weed seed germination
A pre-emergent application of Wilson Garden Weeder with Corn Gluten Meal at the 300 g per m2 rate provides inhibition of weed seed germination, including annual bluegrass, black medic, black nightshade, buckhorn plantain, catchweed bedstraw, lamb's-quarters, creeping bentgrass, curly dock, dandelion, giant foxtail, large crabgrass, orchard grass, purslane, white clover, redroot pigweed, and smooth crabgrass in flower, vegetable, and fruit gardens.
There are a few non-conventional herbicides for weed management in domestic flower, vegetable, and fruit gardens. The expansion of corn gluten meal for use in gardens may provide a useful tool for pre-emergent weed management to home gardeners.
Labels of registered pesticide products include specific instructions for use. Directions include risk-reduction measures to protect human and environmental health. These directions must be followed by law.
The key risk-reduction measures on the technical and end-use product labels to address the potential risks identified in this assessment are as follows.
The signal words "POTENTIAL SENSITIZER" and "CAUTION EYE IRRITANT" are present on the principal display panels of the labels of Corn Gluten Technical and Wilson Garden Weeder with Corn Gluten Meal.
Both the technical and end-use product labels have precautionary statements, such as "Avoid contact with skin, eyes or clothing," "May cause sensitization," and "Avoid breathing/inhaling dusts."
The end-use product label also instructs users not to apply the product if a member of the household has a sensitivity or allergy to corn, and not to apply under windy conditions.
The following additional statement: "Keep pets away from treated areas until the applied product is no longer visible" is also required on the end-use product label.
Before making a final registration decision on corn gluten meal, the PMRA will consider all comments received from the public in response to Proposed Registration Decision PRD2013-17, Corn Gluten Meal. The PMRA will accept written comments on Proposed Registration Decision PRD2013-17, Corn Gluten Meal up to 45 days from the date of publication of Proposed Registration Decision PRD2013-17, Corn Gluten Meal. Please forward all comments to Publications. The PMRA will then publish a Registration Decision, which will include its decision, the reasons for it, a summary of comments received on the proposed final decision and the Agency's response to these comments.
When the PMRA makes its registration decision, it will publish a Registration Decision on corn gluten meal (based on the Science Evaluation of Proposed Registration Decision PRD2013-17, Corn Gluten Meal). In addition, the test data referenced in Proposed Registration Decision PRD2013-17, Corn Gluten Meal will be available for public inspection, upon application, in the PMRA's Reading Room (located in Ottawa).