Proposed Registration Decision PRD2022-17, Florpyrauxifen-benzyl, Milestone NXT Herbicide, Restore NXT Herbicide, GF‑3206 Herbicide, GF-3301 Aquatic Herbicide, and ProcellaCOR FX Herbicide

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Pest Management Regulatory Agency
15 December 2022
ISSN: 1925-0886 (PDF version)
Catalogue number: H113-9/2022-17E-PDF (PDF version)

Summary

Table of contents

• Proposed registration decision for Florpyrauxifen-benzyl
• What does Health Canada consider when making a registration decision?
• What is Florpyrauxifen-benzyl?
• Health considerations
• Environmental considerations
• Value considerations
• Measures to minimize risk
• Next steps
• Other information

Proposed registration decision for Florpyrauxifen-benzyl

Health Canada’s Pest Management Regulatory Agency (PMRA), under the authority of the Pest Control Products Act, is proposing registration for the sale and use of Rinskor Active, Milestone NXT Herbicide, Restore NXT Herbicide, GF-3206 Herbicide, GF-3301 Aquatic Herbicide and ProcellaCOR FX Herbicide, containing the technical grade active ingredient florpyrauxifen-benzyl, for weed management in hazelnut and non-agricultural/industrial vegetation management including many invasive species, as well as for aquatic vegetation management to control invasive plants both in and around water.

The proposed end-use products Milestone NXT Herbicide and Restore NXT Herbicide are coformulations of florpyrauxifen-benzyl and aminopyralid present as potassium salt. Aminopyralid is a registered herbicide active ingredient (REG2007-01 Aminopyralid). The potassium salt represents a new salt form of aminopyralid. The proposed registrations do not represent expansions of use from currently registered uses of aminopyralid.

An evaluation of available scientific information found that, under the approved conditions of use, the health and environmental risks and the value of the pest control products are acceptable.

This summary describes the key points of the evaluation, while the Science evaluation of Proposed Registration Decision PRD2022-17, Florpyrauxifen-benzyl, Milestone NXT Herbicide, Restore NXT Herbicide, GF‑3206 Herbicide, GF-3301 Aquatic Herbicide, and ProcellaCOR FX Herbicide provides detailed technical information on the human health, environmental and value assessments of florpyrauxifen-benzyl and Milestone NXT Herbicide, Restore NXT Herbicide, GF-3206 Herbicide, GF-3301 Aquatic Herbicide and ProcellaCOR FX Herbicide.

What does Health Canada consider when making a registration decision?

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^{Footnote 1} 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^{Footnote 2} 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. 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:

• Protecting Your Health and the Environment
• Pesticide Registration Process
• Pesticide Risk Reduction Program.

Before making a final registration decision on florpyrauxifen-benzyl, Milestone NXT Herbicide, Restore NXT Herbicide, GF-3206 Herbicide, GF-3301 Aquatic Herbicide and ProcellaCOR FX Herbicide, Health Canada’s PMRA will consider any comments received from the public in response to this consultation document.^{Footnote 3} Health Canada will then publish a Registration Decision^{Footnote 4} on florpyrauxifen-benzyl, Milestone NXT Herbicide, Restore NXT Herbicide, GF-3206 Herbicide, GF-3301 Aquatic Herbicide and ProcellaCOR FX Herbicide, which will include the decision, the reasons for it, a summary of comments received on the proposed registration decision and Health Canada’s response to these comments.

For more details on the information presented in this summary, please refer to the Science evaluation of PRD2022-17.

What is Florpyrauxifen-benzyl?

Florpyrauxifen-benzyl is a new selective herbicide belonging to the arylpicolinate class of herbicides. It acts as a synthetic plant hormone by mimicking the natural plant hormone auxin and disrupting growth processes in susceptible plants. Excessive auxin causes alterations in cell wall elasticity resulting in leaf curling and interference with nutrient transport.

Health considerations

Can approved uses of Florpyrauxifen-benzyl affect human health?

End-use products containing florpyrauxifen-benzyl are unlikely to affect your health when used according to proposed label directions.

Potential exposure to florpyrauxifen-benzyl may occur through the diet (food and drinking water), when handling and applying the end-use products, or when coming into contact with treated water and surfaces. When assessing health risks, two key factors are considered:

• the levels at which no health effects occur and
• the levels to which people may be exposed.

The dose levels used to assess risks are established to protect the most sensitive human population (for example, children and nursing mothers). As such, sex and gender are taken into account in the risk assessment. Only uses for which the exposure is well below levels that cause no effects in animal testing are considered acceptable for registration.

Toxicology studies in laboratory animals describe potential health effects from varying levels of exposure to a chemical and identify the dose level at which no effects are observed. The health effects noted in animals occur at dose levels more than 100-times higher (and often much higher) than levels to which humans are normally exposed when pesticide products are used according to label directions.

In laboratory animals, the technical grade active ingredient florpyrauxifen-benzyl was of low acute toxicity by the oral, dermal and inhalation routes. Florpyrauxifen-benzyl was minimally irritating to the eyes and non-irritating to the skin. It did cause an allergic skin reaction; consequently, the hazard statement “POTENTIAL SKIN SENSITIZER” is required on the label.

The acute toxicity of GF-3301 Aquatic Herbicide and ProcellaCOR FX Herbicide containing florpyrauxifen-benzyl, was low via the oral, dermal and inhalation routes of exposure. They were minimally irritating to the eyes and skin and did not cause an allergic skin reaction.

The acute toxicity of GF-3206 Herbicide containing florpyrauxifen-benzyl was low via the oral, dermal and inhalation routes of exposure. It was minimally irritating to the eyes, slightly irritating to the skin and did not cause an allergic skin reaction.

The acute toxicity of Milestone NXT Herbicide containing florpyrauxifen-benzyl and aminopyralid (present as potassium salt) was low via the oral, dermal and inhalation routes of exposure. It was minimally irritating to the eyes, slightly irritating to the skin and did not cause an allergic skin reaction.

The acute toxicity of Restore NXT Herbicide containing florpyrauxifen-benzyl and aminopyralid (present as a potassium salt) was low via the oral, dermal and inhalation routes of exposure. It was non-irritating to the eyes and skin and was not a dermal sensitizer.

Registrant-supplied short- and long-term (lifetime) animal toxicity tests, as well as information from the published scientific literature, were assessed for the potential of florpyrauxifen-benzyl to cause neurotoxicity, immunotoxicity, chronic toxicity, cancer, reproductive and developmental toxicity, and various other effects. The most sensitive endpoints for risk assessment were effects on body weight. There was no evidence of increased sensitivity of the young compared to adult animals. The risk assessment is protective against the effects noted above and other potential effects by ensuring that the level of exposure to humans is well below the lowest dose level at which these effects occurred in animal tests.

Residues in water and food

Dietary risks from food and drinking water are not of health concern.

Studies in laboratory animals showed no acute health effects. Consequently, a single dose of florpryrauxifen-benzyl is not likely to cause acute health effects in the general population (including infants and children).

Aggregate chronic dietary (food plus drinking water) intake estimates indicated that the general population and all population subgroups are exposed to less than 1% of the acceptable daily intake (ADI), and therefore are not of health concern.

The Food and Drugs Act prohibits the sale of adulterated food, that is, food containing a pesticide residue that exceeds the established maximum residue limit (MRL). Pesticide MRLs are established for Food and Drugs Act purposes through the evaluation of scientific data under the Pest Control Products Act. Given that dietary risks from the consumption of foods are shown to be acceptable when florpyrauxifen-benzyl is used according to the supported label directions, MRLs are being proposed as a result of this assessment (refer to PMRL2022-23, Florpyrauxifen-benzyl).

MRLs for florpyrauxifen-benzyl determined from the acceptable residue trials conducted throughout Canada and the United States, which also includes growing regions representative of Canada, and in Australia, Southern Europe, Argentina, Brazil, China and Japan, can be found in the Science evaluation of PRD2022-17.

A number of these florpyrauxifen-benzyl products are also formulated with the active ingredientaminopyralid, present as potassium salt. Aminopyralid is already registered for these uses in Canada, and residues in treated commodities will be covered under the existing MRLs.

Occupational risks from handling GF-3206 Herbicide, Milestone NXT Herbicide, Restore NXT Herbicide, GF-3301 Aquatic Herbicide and ProcellaCOR FX Herbicide

Occupational risks are not of health concern when GF-3206 Herbicide, Milestone NXT Herbicide, Restore NXT Herbicide, GF-3301 Aquatic Herbicide and ProcellaCOR FX Herbicide are used according to the proposed label directions, which include protective measures.

Workers mixing, loading or applying GF-3206 Herbicide, Milestone NXT Herbicide, Restore NXT Herbicide, GF-3301 Aquatic Herbicide or ProcellaCOR FX Herbicide and workers entering areas recently treated with these end-use products can come in direct contact with florpyrauxifen-benzyl. Therefore, the label specifies that anyone mixing, loading and applying GF-3206 Herbicide, Milestone NXT Herbicide, Restore NXT Herbicide, GF-3301 Aquatic Herbicide or ProcellaCOR FX Herbicide must wear a long-sleeved shirt, long pants, chemical-resistant gloves, socks and shoes. For GF-3206 Herbicide, Milestone NXT Herbicide, Restore NXT Herbicide, the label also requires that workers do not enter or be allowed into treated areas during the restricted-entry interval (REI) of 12 hours, except for industrial and other non-crop areas where entry is permitted once sprays have dried. Taking into consideration the label instructions and the duration of exposure for handlers and postapplication workers, the risks to these individuals are not of health concern.

Risks in residential and other non-occupational environments

Risks in residential and other non-occupational environments are not of health concern when GF-3301 Aquatic Herbicide and ProcellaCOR FX Herbicide are used according to the proposed label directions.

Water treated with GF-3301 Aquatic Herbicide and ProcellaCOR FX Herbicide can be used to irrigate golf courses and residential turf and gardens. As such, individuals can come into direct contact with florpyrauxifen-benzyl when golfing in the irrigated turf, irrigating residential turf and gardens, and entering irrigated residential turf and gardens. Taking into consideration the label instructions and the duration of exposure, the risks to these individuals are not of health concern.

Risks from swimming in treated water are also not of health concern.

Risks to bystanders

Bystander risks are not of health concern when GF-3206 Herbicide, Milestone NXT Herbicide, Restore NXT Herbicide, GF-3301 Aquatic Herbicide and ProcellaCOR FX Herbicide are used according to the proposed label directions and spray drift restrictions are observed.

Risks to bystanders in non-crop areas (in other words, hikers) are not of health concern. In addition, a standard label statement to protect against drift during application is on the label. Therefore, health risks to other bystanders are also not of concern.

Environmental considerations

What happens when Florpyrauxifen-benzyl is introduced into the environment?

When used according to label directions, environmental risks associated with florpyrauxifen-benzyl and its associated end-use products are acceptable.

Florpyrauxifen-benzyl enters the environment when its end-use products are used to control aquatic and terrestrial weeds, including invasive plant species.

• The aquatic end-use products (GF-3301 Aquatic Herbicide and ProcellaCOR FX Herbicide) are applied to water by foliar spray using boat or ground equipment, or by direct injection into water. Treated waters can also be used for irrigation.
• The terrestrial end-use products (GF-3206 Herbicide, Milestone NXT Herbicide and Restore NXT Herbicide) are applied to agricultural and non-agricultural areas using aerial or ground equipment.

In the environment, florpyrauxifen-benzyl is quickly broken down to its acid form (florpyrauxifen acid) and other transformation products by microorganisms and via interactions with water and sunlight. Florpyrauxifen acid is both an active form of the pesticide and a transformation product of florpyrauxifen-benzyl, and degrades more slowly than florpyrauxifen-benzyl. Most transformation products of florpyrauxifen-benzyl also degrade relatively quickly in water and sediment. Certain transformation products of florpyrauxifen-benzyl, namely florpyrauxifen acid, hydroxy acid, and nitro hydroxy acid, may move through soil and reach groundwater. Florpyrauxifen-benzyl and its transformation products are not expected to be found in air or to travel long distances in the atmosphere from its application sites. They are also not expected to accumulate in the tissues of animals.

When used according to label directions, florpyrauxifen-benzyl and its transformation products do not pose a risk to wild mammals, birds, beneficial invertebrates, earthworms, bees, aquatic invertebrates, fish, amphibians, or algae. While florpyrauxifen-benzyl and florpyrauxifen acid may pose risks to sensitive non-target terrestrial plants and aquatic vascular plants, the PMRA recognizes that control of invasive species is necessary to help protect habitats for native species. When used according to label directions, florpyrauxifen-benzyl products will have the desired effect of controlling invasive terrestrial and aquatic plant species that pose a risk to sensitive habitats, which will benefit the aquatic plant community. Preventative measures and use restrictions are required to reduce exposure to plants that are not pests.

Value considerations

What is the value of GF-3206 Herbicide, Milestone NXT Herbicide, Restore NXT Herbicide, GF-3301 Aquatic Herbicide and ProcellaCOR FX Herbicide?

GF-3206 Herbicide is formulated as an emulsifiable concentrate containing 19.91 g/L florpyrauxifen (present as benzyl ester). It provides selective control of many annual and perennial broadleaf weeds and invasive plants and shrubs in rangeland, permanent pasture, rights-of-way, industrial and other non-crop areas. GF-3206 Herbicide can also be used in hazelnut production for weed management.

Milestone NXT Herbicide is formulated as a wettable granule containing 4.77% florpyrauxifen (present as benzyl ester) and 60% aminopyralid (present as potassium salt). It provides selective control of many annual and perennial broadleaf weeds and invasive plants and shrubs in rangeland, permanent pasture, rights-of-way, industrial and other non-crop areas.

Restore NXT Herbicide is formulated as a soluble concentrate and also contains both florpyrauxifen (6.36 g/L, present as benzyl ester) and aminopyralid (80 g/L, present as potassium salt). Restore NXT Herbicide also provides selective control of many annual and perennial broadleaf weeds and invasive plants and shrubs in rangeland, permanent pasture, rights-of-way, industrial and other non-crop areas.

GF-3301 Aquatic Herbicide is formulated as a soluble concentrate containing 238.4 g/L florpyrauxifen (present as benzyl ester). It is intended as a selective herbicide for the management of invasive freshwater aquatic vegetation in still or slow-moving waters of ponds, lakes, reservoirs, streams, rivers, and canals (including shoreline and riparian areas in or adjacent to these waterbodies).

ProcellaCOR FX Herbicide is also formulated as a soluble concentrate containing 238.4 g/L florpyrauxifen (present as benzyl ester) and shares an identical use pattern to GF-3301 Aquatic Herbicide.

Terrestrial and aquatic invasive plants are a global phenomenon that have received more attention in Canada in the last decade. Registrations of GF-3206 Herbicide, Milestone NXT Herbicide and Restore NXT Herbicide provide users with options to control a wide range of annual and perennial broadleaf weeds and invasive plants and shrubs in rangeland, permanent pasture, rights-of-way, industrial and other non-crop areas. GF-3301 Aquatic Herbicide and ProcellaCOR FX Herbicide will provide provincial authorities and partners with a valuable tool and long-term solution to manage invasive aquatic species in and around aquatic sites.

Measures to minimize risk

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 being proposed on the labels of Rinskor Active, Milestone NXT Herbicide, Restore NXT Herbicide, GF-3206 Herbicide, GF-3301 Aquatic Herbicide and ProcellaCOR FX Herbicide to address the potential risks identified in this assessment are as follows.

Key risk-reduction measures - Human health

To reduce the potential of workers coming into direct contact with florpyrauxifen-benzyl dermally, workers mixing, loading and applying GF-3206 Herbicide, Milestone NXT Herbicide, Restore NXT Herbicide, GF-3301 Aquatic Herbicide and ProcellaCOR FX Herbicide and performing cleaning and repair activities must wear a long-sleeved shirt, long pants, chemical-resistant gloves, socks and shoes. For GF-3206 Herbicide, Milestone NXT Herbicide and Restore NXT Herbicide, the label also requires that workers do not enter or be allowed entry into treated orchards, pastures and rangelands during the REI of 12 hours; and do not enter or allow others to enter treated industrial and other non-crop areas until sprays have dried. Furthermore, a standard label statement to protect against drift during application is present on the label.

Key risk-reduction measures - Environment

To minimize exposure and reduce risks to non-target terrestrial plants and aquatic vascular plants from the aquatic end-use products, GF-3301 Aquatic Herbicide and ProcellaCOR FX Herbicide, the following mitigation measures are included on product labels:

• Classification of the products as restricted:
  • GF-3301 Aquatic Herbicide and ProcellaCOR FX Herbicide are registered for use by, or under permit from, and after consultation with provincial and federal fish and wildlife agencies.
  • Nature of Restriction: This is a restricted product that must be used in the manner authorized. This product is only to be used by individuals holding an appropriate pesticide applicator certificate or license recognized by the provincial/territorial pesticide regulatory authority where the pesticide application is to occur. This registration is granted under the Pest Control Products Act and does not exempt the user from any other legislative requirements. Use of this product in or immediately adjacent to water bodies must be appropriately authorized and used in accordance with the Fisheries Act and Regulations, such as the Aquatic Invasive Species Regulations, and in accordance with any other required federal and provincial authorizations. Consult with provincial regulatory authorities on any authorizations required prior to use of this product.
• Precautionary statements indicating toxicity to terrestrial and aquatic vascular plants
• Advisory distances to reduce exposure from spray drift to sensitive terrestrial plants
• Precautionary label statements against irrigating lawns that contain sensitive, non-grass, plants

To minimize exposure and reduce risks to non-target terrestrial plants and aquatic vascular plants from the terrestrial end-use products, GF-3206 Herbicide, Milestone NXT Herbicide and Restore NXT Herbicide, the following mitigation measures are included on product labels:

• Mandatory spray buffer zones to minimize exposure of terrestrial and aquatic habitats from spray drift
• Precautionary label statements for runoff, leaching to groundwater, and contamination of water sources
• Precautionary statements indicating toxicity to terrestrial and aquatic vascular plants

Next steps

Before making a final registration decision on florpyrauxifen-benzyl, Milestone NXT Herbicide, Restore NXT Herbicide, GF-3206 Herbicide, GF-3301 Aquatic Herbicide and ProcellaCOR FX Herbicide, Health Canada’s PMRA will consider any comments received from the public in response to PRD2022-17. Health Canada will accept written comments on this proposal up to 45 days from the date of publication of PRD2022-17. Please note that, to comply with Canada's international trade obligations, consultation on the proposed MRLs will also be conducted internationally via a notification to the World Trade Organization. Please forward all comments to Publications. Health Canada will then publish a Registration Decision, which will include its decision, the reasons for it, a summary of comments received on the proposed decision and Health Canada’s response to these comments.

Other information

When the Health Canada makes its registration decision, it will publish a Registration Decision on florpyrauxifen-benzyl, Milestone NXT Herbicide, Restore NXT Herbicide, GF-3206 Herbicide, GF-3301 Aquatic Herbicide and ProcellaCOR FX Herbicide (based on the Science evaluation of PRD2022-17). In addition, the test data referenced in this consultation document will be available for public inspection, upon application, in the PMRA’s Reading Room. For more information, please contact the PMRA’s Pest Management Information Service.