Proposed Re-evaluation Decision PRVD2023-04, Agrobacterium radiobacter strain K84 and Its Associated End-use Product

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Pest Management Regulatory Agency
28 August 2023
ISSN: 1925-0967 (PDF version)
Catalogue number: H113-27/2023-4E-PDF (PDF version)

Table of contents

• Proposed Re-evaluation Decision
• Next steps
• Additional scientific information

Proposed Re-evaluation Decision

Under the Pest Control Products Act, all registered pesticides must be re-evaluated regularly by Health Canada's Pest Management Regulatory Agency (PMRA) to ensure that they continue to meet health and environmental safety standards and continue to have value. The re-evaluation considers data and information from various sources such as information from pesticide manufacturers, incident reports, and other regulatory agencies. Health Canada applies internationally accepted risk assessment methods, risk management approaches and policies to all re-evaluations.

Proposed Re-evaluation Decision PRVD2023-04, Agrobacterium radiobacter strain K84 and Its Associated End-use Product presents the proposed regulatory decision for the re-evaluation of Agrobacterium radiobacter strain K84.

Agrobacterium radiobacter strain K84 is a naturally occurring soil-dwelling, gram-negative, short-rod aerobic bacterium used as a bactericide to control crown gall disease on seeds and nursery stock of stone fruit, pome fruit, berries, tree nuts, ornamental flowers, shrubs and trees as well as grapes and hops. The mode of action of Agrobacterium radiobacter strain K84 is through direct competition that is primarily facilitated by the production of a bacteriocin specific against certain pathogenic strains of Agrobacterium spp.

There is one Commercial Class end-use product containing Agrobacterium radiobacter strain K84 registered in Canada (Appendix I of PRVD2023-04). The product is formulated as a live organism in damp powder and is mixed with water then applied to seeds, seedlings and cuttings (rootstock and rooted) at planting as a dip treatment only, before potential exposure to the disease. It acts as a preventative treatment and therefore is applied at a high application rate to protect any wound sites against pathogenic invasion.

Agrobacterium radiobacter strain K84 is of value to commercial nursery growers as it is the only pesticide registered to prevent crown gall disease in plants. The potential risks to human health (occupational, residential, bystander and dietary) and the environment are considered to be acceptable when the product containing Agrobacterium radiobacter strain K84 is used according to current label directions.

Under the authority of the Pest Control Products Act and based on an evaluation of currently available scientific information, the product containing Agrobacterium radiobacter strain K84 (Appendix I of PRVD2023-04) is being proposed for continued registration in Canada with the proposed label updates (a best practice statement and a label amendment to meet the current labelling standards, as outlined in Appendix II of PRVD2023-04). Proposed label changes include amending the existing personal protective equipment statement and adding a precaution statement for children and animals.

The product containing Agrobacterium radiobacter strain K84 registered in Canada is subject to this proposed re-evaluation decision. This document is subject to a public consultation,^{Footnote 1} during which written comments and additional information may be submitted to PMRA Publications. The final re-evaluation decision will be published taking into consideration the comments and information received during the consultation period.

Next steps

The public, including the registrant and stakeholders, are encouraged to submit written comments and additional information during the 90-day public consultation period upon publication of PRVD2023-04.

All comments received during the 90-day public consultation period will be taken into consideration in preparation of the re-evaluation decision document,^{Footnote 2} which could result in revised risk mitigation measures. The re-evaluation decision document will include the final re-evaluation decision, the reasons for it and a summary of comments received on the proposed re-evaluation decision with Health Canada's responses.

Additional scientific information

Additional scientific data are not required.