Proposed Registration Decision PRD2016-23, Pyriofenone

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Pest Management Regulatory Agency
29 August 2016
ISSN: 1925-0886 (PDF version)
Catalogue number: H113-9/2016-23E-PDF (PDF version)

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Pyriofenone
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Summary

Table of Contents

Proposed Registration Decision for Pyriofenone

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 Technical Pyriofenone Fungicide and Pyriofenone 300SC Fungicide, containing the technical grade active ingredient pyriofenone, to control or suppress powdery mildew in cucurbits and certain berry crops.

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 PRD2016-23, Pyriofenone provides detailed technical information on the human health, environmental and value assessments of Technical Pyriofenone Fungicide and Pyriofenone 300SC Fungicide.

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 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. 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 Pyriofenone, the PMRA will consider any comments received from the public in response to this consultation document. The PMRA will then publish a Registration Decision on Pyriofenone, 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 PRD2016-23, Pyriofenone.

What Is Pyriofenone?

Pyriofenone is a fungicide active ingredient with preventative and systemic properties for control or suppression of powdery mildew on various crops.

Health Considerations

Can Approved Uses of Pyriofenone Affect Human Health?

Pyriofenone 300SC Fungicide is unlikely to affect human health when used according to label directions.

Potential exposure to pyriofenone may occur through the diet (food and water) or when handling and applying Pyriofenone 300SC Fungicide. When assessing health risks, two key factors are considered:

  • the levels where 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). 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 where no effects are observed. The health effects noted in animals occur at doses more than 100-times higher (and often much higher) than levels to which humans are normally exposed when pesticide-containing products are used according to label directions.

In laboratory animals, pyriofenone and Pyriofenone 300SC Fungicide, were 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 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 susceptibility of the young in reproduction or developmental toxicity studies. The risk assessment protects against the effects of pyriofenone by ensuring that the level of human exposure is well below the lowest dose 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.

Aggregate dietary intake estimates (food plus drinking water) revealed that the general population and children 1-2 years old, the subpopulation which would ingest the most pyriofenone 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.

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 representative commodities of Crop Group 9, Cucurbit Vegetables, and of Crop subgroup 13-07A (Caneberries), Crop subgroup 13-07B (Bushberries), Crop Subgroup 13-07D (Small fruit climbing) and Crop subgroup 13-07G (Low growing berries) are acceptable, in addition to residue trials conducted throughout Europe using pyriofenone on grapes. The MRLs for this active ingredient can be found in the Science Evaluation section of this consultation document.

Risk in Residential and Other Non-Occupational Environments

Risk to bystanders is not of concern when Pyriofenone 300SC Fungicide is used according to the proposed label directions.

Application is limited to agricultural crops, only when there is low risk of drift to areas of human habitation or activity, such as houses, cottages, schools and recreational areas, taking into consideration wind speed, wind direction, temperature inversions, application equipment and sprayer settings. Therefore, bystander exposure is expected to be minimal.

The occupational re-entry worker exposure to treated crops was not of concern and, therefore, any potential exposure to bystanders in a pick-your-own scenario is also not of concern.

Occupational Risks From Handling Pyriofenone 300SC Fungicide

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

Farmers and custom applicators who mix, load or apply Pyriofenone 300SC Fungicide, as well as field workers re-entering freshly treated fields, can come in direct contact with pyriofenone residues on the skin. Therefore, the label specifies that anyone mixing/loading and applying Pyriofenone 300SC Fungicide must wear long-sleeved shirt and long pants, socks, shoes, and chemical-resistant gloves made of any waterproof material. The label, Pyriofenone 300SC Fungicide, also requires that workers do not enter treated fields for 12 hours after application. Taking into consideration these label statements, the number of applications, and the expectation of the exposure period for handlers and workers, the risk to these individuals from exposure to pyriofenone are not a concern.

For bystanders, exposure is expected to be much less than that for workers and is considered negligible. Therefore, health risks to bystanders are not of concern.

Environmental Considerations

What Happens When Pyriofenone Is Introduced Into the Environment?

Pyriofenone is not expected to pose risks of concern to the environment when used according to label directions.

Pyriofenone enters the environment when it is sprayed on cucurbit vegetables, berries and other small fruit plants to protect them against fungi. Once on the leaves, pyriofenone may be distributed throughout the plant.

In the terrestrial environment, pyriofenone residues tend to bind to soil particles and remain in the top soil layers. Pyriofenone can be broken down by microorganisms faster in soils low in oxygen. Pyriofenone is slightly persistent to persistent in soil, and can carry over to the following growing season. Pyriofenone has a slight potential for mobility in some soils and has limited potential to move through the soil to enter groundwater.

Pyriofenone does not react with water and has a limited potential to transform under sunlight. If it enters the aquatic environment, pyriofenone tends to move from the water column to the sediments. Pyriofenone residues tend to bind to sediment particles and can be broken down faster by microorganisms in sediments low in oxygen. Pyriofenone is not expected to accumulate in fish tissues.

Pyriofenone formed only two major degradation products in control laboratory studies. These two products are structurally similar to pyriofenone and tend to be produced at higher concentrations in the absence of oxygen in both the soil and water/sediment systems. Pyriofenone's degradation products are not expected to be of concern to the environment. Residues of pyriofenone are not expected to volatilize to air or accumulate in the tissues of animals.

Overall, when used according to the label directions, pyriofenone is expected to pose a negligible risk to terrestrial invertebrates, birds, mammals, terrestrial and aquatic plants, freshwater invertebrates, fish (freshwater and marine) and amphibians. Pyriofenone may pose a slight risk to freshwater algae and marine invertebrates. In order to minimize the potential risk of pyriofenone to these organisms, precautionary label statements, as well as mitigation measures, are specified on the label of the end-use product (refer to section on Measures to Minimize Risk below). Pyriofenone 300SC Fungicide is not expected to pose risks of concern to the environment when used according to label directions.

Value Considerations

What Is the Value of Pyriofenone 300SC Fungicide?

Pyriofenone 300SC Fungicide contains a new active ingredient, pyriofenone, which will control or suppress powdery mildew in cucurbits and certain berry crops.

Pyriofenone 300SC Fungicide has been identified as a priority by Canadian growers for control of powdery mildew on blackberry and cucumber. There are currently other conventional and non-conventional fungicides registered for control or suppression of powdery mildew on the crops. Nevertheless, the addition of a new active ingredient from a different mode of action group will offer an alternative to the growers to manage powdery mildew, and help address resistance development in susceptible fungi.

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 label of Pyriofenone 300SC Fungicide to address the potential risks identified in this assessment are as follows.

Key Risk-Reduction Measures

Human Health

Because there is a concern with users coming into direct contact with pyriofenone on the skin, anyone mixing/loading and applying Pyriofenone 300SC Fungicide must wear a long-sleeved shirt and long pants, socks, shoes, and chemical-resistant gloves made of any waterproof material. In addition, standard label statements to protect against drift during application are on the label.

Environment

Additional label statements under the Environmental Precautions section are required to inform the user that:

  • Pyriofenone is persistent and may carry over to the following growing season;
  • Pyriofenone is toxic to aquatic organisms; and
  • To mitigate potential exposure of aquatic organisms through spray drift, spray buffer zones of 1 metre are required to protect sensitive freshwater and marine aquatic habitats and must be specified on the labels of Pyriofenone 300SC Fungicide.

Next Steps

Before making a final registration decision on Pyriofenone, the PMRA will consider any comments received from the public in response to PRD2016-23, Pyriofenone. The PMRA will accept written comments on PRD2016-23 up to 45 days from the date of publication of PRD2016-23. 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. 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.

Other Information

When the PMRA makes its registration decision, it will publish a Registration Decision on Pyriofenone (based on the Science Evaluation of PRD2016-23, Pyriofenone). In addition, the test data referenced in PRD2016-23 will be available for public inspection, upon application, in the PMRA's Reading Room (located in Ottawa).

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