Proposed Registration Decision PRD2023-08, Pyriofenone 300 SC Fungicide, containing pyriofenone

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Pest Management Regulatory Agency
10 October 2023
ISSN: 1925-0886 (PDF version)
Catalogue number: H113-9/2023-8E-PDF (PDF version)

Summary

Table of contents

• Proposed registration decision for Pyriofenone 300 SC Fungicide
• What does Health Canada consider when making a registration decision?
• What is pyriofenone?
• Health considerations
• Environmental considerations
• Value considerations
• Measures to minimize risk
• Next steps
• Other information

Proposed registration decision for Pyriofenone 300 SC Fungicide

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 Pyriofenone 300 SC Fungicide, containing the technical grade active ingredient pyriofenone, to suppress/control powdery mildew on greenhouse ornamentals, greenhouse pepper, greenhouse eggplant, greenhouse cucumber and greenhouse tomato. This evaluation was completed under the User Requested Minor Use Label Expansion program, which is a cooperative program between Agriculture and Agri-Food Canada and Health Canada's Pest Management Regulatory Agency and includes participation by sponsor groups, manufacturers, and both provincial and federal governments.

The end use product, Pyriofenone 300 SC Fungicide, and the active ingredient, pyriofenone, are currently registered for the control of powdery mildew on field grown food crops and outdoor ornamentals. For details, see Proposed Registration Decision PRD2016-23, Pyriofenone, and Registration Decision RD2016-33, Pyriofenone.

An evaluation of available scientific information found that, under the approved conditions of use, the health and environmental risks and the value of Pyriofenone 300 SC, containing pyriofenone, are acceptable.

This summary describes the key points of the evaluation, while the Science evaluation of Proposed Registration Decision PRD2023-08, Pyriofenone 300 SC Fungicide provides detailed technical information on the human health, environmental and value assessments of Pyriofenone 300 SC Fungicide, containing pyriofenone, when applied to greenhouse ornamentals and greenhouse cucumber, pepper, eggplant and tomato.

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 on how Health Canada regulates pesticides, the assessment process and risk-reduction programs, please visit the Pesticides section of the Canada.ca website.

Before making a final registration decision on Pyriofenone 300 SC Fungicide, containing pyriofenone, 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 Pyriofenone 300 SC Fungicide, containing pyriofenone, 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 PRD2023-08.

What is pyriofenone?

Pyriofenone disrupts cellular activity, leading to reduced growth and reproduction of the fungus. This active ingredient is effective against powdery mildew on agricultural and ornamental crops.

Health considerations

Can approved uses of pyriofenone affect human health?

Pyriofenone 300 SC Fungicide, containing pyriofenone, is unlikely to affect your health when used according to label directions.

Potential exposure to pyriofenone may occur through the diet (food and drinking water) or when coming into contact with treated surfaces or when handling and applying Pyriofenone 300 SC Fungicide. 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 where 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 pyriofenone and the associated end-use product Pyriofenone 300 SC Fungicide were both of low acute toxicity by the oral, dermal, and inhalation routes of exposure. They were both non-irritating to the eyes and skin and did not cause an allergic skin reaction.

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 pyriofenone to cause neurotoxicity, immunotoxicity, chronic toxicity, cancer, reproductive and developmental toxicity, and various other effects. The most sensitive endpoints for risk assessment were abortions and adverse effects noted in the kidneys. There was no evidence of increased sensitivity of the young compared to adult animals. The risk assessment protects 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.

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

Aggregate dietary intake estimates (food plus drinking water) revealed that the general population and children 1–2 years olds, the subpopulation which would ingest the most pyriofenone residues relative to body weight, are expected to be exposed to less than 9% of the acceptable daily intake. Based on these estimates, the chronic dietary risk from pyriofenone is not of health concern for all population subgroups.

Pyriofenone is not carcinogenic; therefore, a cancer dietary risk assessment is not required.

Animal studies revealed no acute health effects. Consequently, a single dose of pyriofenone is not likely to cause acute health effects in the general population (including infants and children).

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. Food containing a pesticide residue that does not exceed the established MRL does not pose an unacceptable health risk.

Residue trials conducted throughout Canada and the United States using pyriofenone on greenhouse tomatoes, greenhouse peppers and greenhouse cucumbers are acceptable. The MRLs for this active ingredient can be found in the Science evaluation section of PRD2023-08.

Occupational risks are not of health concern when Pyriofenone 300 SC Fungicideis used according to the proposed label directions, which include protective measures.

Workers mixing, loading or applying Pyriofenone 300 SC Fungicide, and workers entering recently treated greenhouses can come in direct contact with pyriofenone residues on the skin and through inhalation. Therefore, the label specifies that anyone mixing, loading and applying Pyriofenone 300 SC Fungicidemust wear a long-sleeved shirt, long pants, chemical-resistant gloves, socks and shoes. The label also requires that workers do not enter or be allowed into treated areas during the restricted-entry interval (REI) of 12 hours. Taking into consideration the label statements, the number of applications and the duration of exposure for handlers and postapplication workers, the risks to these individuals are not of health concern.

Health risks to bystanders

Bystander risks are not of health concern when Pyriofenone 300SC Fungicideis used according to the proposed label directions and spray drift restrictions are observed.

A standard label statement to protect against drift during application is on the label. Therefore, health risks to bystanders are not of concern.

Environmental considerations

Environmental risks associated with the use of pyriofenone are acceptable when Pyriofenone 300SC Fungicide is used according to label directions.

The new uses of pyriofenone on greenhouse ornamentals and greenhouse food crops may result in exposure to beneficial arthropods and pollinators used for greenhouse pest management and pollination. Considering the application rates and patterns for the greenhouse uses, and the ecotoxicity data available in PRD2016-23, risks from pyriofenone were found to be acceptable for beneficial arthropods and pollinators in greenhouses. A label statement is required to prevent greenhouse effluent containing pyriofenone from entering aquatic systems.

Value considerations

What is the value of Pyriofenone 300 SC Fungicide?

Pyriofenone is a fungicide for use against powdery mildew on ornamental crops and certain vegetable crops grown in the greenhouse.

Powdery mildew affects the aesthetic quality and marketability of ornamental plants and can negatively affect the yield and quality of vegetable crops. Canadian growers identified management of powdery mildew on greenhouse ornamental crops as a national priority at the Canadian Minor Use Priority Setting Workshop in 2014. Pyriofenone will contribute to protection against powdery mildew and the management of pathogen resistance.

Measures to minimize risk

Labels of registered pesticide products include specific instructions for use. Directions include risk-reduction measures to protect human health and the environment. These directions must be followed by law.

The key risk-reduction measures being proposed on the label of Pyriofenone 300 SC Fungicide to address the potential risks identified in this assessment are as follows.

Key risk-reduction measures - Human health

To reduce the potential exposure of workers to pyriofenone through direct contact on the skin or through inhalation, workers mixing, loading and applying Pyriofenone 300 SC Fungicideand performing cleaning and repair activities must wear a long-sleeved shirt, long pants, chemical-resistant gloves, socks and shoes. The label also requires that workers do not enter or be allowed entry into treated greenhouses during the REI of 12 hours. Furthermore, a standard label statement to protect against drift during application and to prevent the use of handheld airblast, misters and foggers are present on the label.

Key risk-reduction measures - Environment

Label statement to prohibit greenhouse effluent containing pyriofenone from entering aquatic systems.

Next steps

Before making a final registration decision on Pyriofenone 300SC Fungicide, Health Canada's PMRA will consider any comments received from the public in response to PRD2023-08. Health Canada will accept written comments on this proposal up to 45 days from the date of publication of PRD2023-08. 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 Pyriofenone 300 SC Fungicide, containing pyriofenone (based on the Science evaluation of PRD2023-08). 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.