Proposed Registration Decision PRD2022-15, Pyrifluquinazon and Pyrifluquinazon 20SC Insecticide

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

Summary

Table of contents

• Proposed registration decision for Pyrifluquinazon and Pyrifluquinazon 20SC Insecticide
• What does Health Canada consider when making a registration decision?
• What is Pyrifluquinazon?
• Health considerations
• Environmental considerations
• Value considerations
• Measures to minimize risk
• Next steps
• Other information

Proposed registration decision for Pyrifluquinazon and Pyrifluquinazon 20SC Insecticide

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 Pyrifluquinazon Technical and Pyrifluquinazon 20SC Insecticide, containing the technical grade active ingredient pyrifluquinazon, for the control of aphids and whiteflies in greenhouse vegetables and greenhouse herbaceous and woody deciduous ornamentals.

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 PRD2022-15, Pyrifluquinazon and Pyrifluquinazon 20SC Insecticide provides detailed technical information on the human health, environmental and value assessments of pyrifluquinazon and Pyrifluquinazon 20SC Insecticide.

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 pyrifluquinazon and Pyrifluquinazon 20SC Insecticide, 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 pyrifluquinazon and Pyrifluquinazon 20SC Insecticide, 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 PRD2022-15.

What is Pyrifluquinazon?

Pyrifluquinazon is an insecticide that acts on the insect nervous system. Pyrifluquinazon controls insects by acting as a feeding blocker that disrupts feeding in plant-sucking insects. This leads to starvation and death as the insects can no longer penetrate plants with their mouthparts.

Pyrifluquinazon displays translaminar (local systemic) movement by entering one side of a leaf and moving to the other leaf surface when applied to foliage. Pyrifluquinazon is the active ingredient in Pyrifluquinazon 20SC Insecticide, which controls aphids and whiteflies in greenhouse lettuce, cucumber, tomato, eggplant and pepper and greenhouse herbaceous and woody deciduous ornamentals.

Health considerations

Can approved uses of Pyrifluquinazon affect human health?

Pyrifluquinazon 20SC Insecticide, containing pyrifluquinazon, is unlikely to affect your health when used according to proposed label directions.

Potential exposure to pyrifluquinazon may occur through the diet (food), when handling and applying the end-use product, or when coming into contact with treated 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 selected 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 pyrifluquinazon was of moderate acute toxicity by the oral route; consequently, the signal word and hazard statement “WARNING – POISON” are required on the label. It was of low acute toxicity dermally and of slight acute toxicity following inhalation exposure. It was minimally irritating to the eyes and non-irritating to the skin, but caused an allergic skin reaction. Consequently, the hazard statement “POTENTIAL SKIN SENSITIZER” is required on the label.

The end-use product Pyrifluquinazon 20SC Insecticide, containing pyrifluquinazon, was of slight acute toxicity by the oral route; consequently, the signal word and hazard statement “CAUTION – POISON” are required on the label. It was of low acute toxicity through the dermal and inhalation routes of exposure. Pyrifluquinazon 20SC Insecticide was minimally irritating to the eyes and skin, but caused an allergic skin reaction. Consequently, the hazard statement “POTENTIAL SKIN SENSITIZER” is required on the label.

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 pyrifluquinazon 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 the nasal passages, altered fetal development, and mortality. There was no evidence to suggest that pyrifluquinazon has the potential to damage genetic material. Pyrifluquinazon did, however, cause testicular tumours in male rats and mice. An increase in benign mammary gland tumours observed in male rats could not be clearly attributed to treatment with pyrifluquinazon. There was an indication that the young were more sensitive than the adult animal. 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.

Residues in food and drinking water

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

Acute dietary (food alone) intake estimates indicated that the general population and all population subgroups including females 13 to 49 years old are exposed to less than 54% of the acute reference dose, and therefore are not of health concern.

Chronic (non-cancer and cancer) dietary (food alone) intake estimates indicated that the general population and all population subgroups are exposed to less than 15% of the acceptable daily intake, 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 pyrifluquinazon is used according to the supported label directions, MRLs are being proposed as a result of this assessment.

MRLs for pyrifluquinazon were determined from the acceptable residue trials conducted throughout Canada on greenhouse tomatoes, peppers, lettuce and cucumbers, the United States on tuberous and corm vegetables, leafy vegetables, Brassica vegetables, fruiting vegetables, cucurbit vegetables, pome fruits, stone fruits, citrus fruits, small fruits vine climbing (except fuzzy kiwifruit), tree nuts, leaf petiole vegetables and cotton, and Japan on tea.

Occupational risks from handling Pyrifluquinazon 20SC Insecticide

Occupational risks are not of health concern when Pyrifluquinazon 20SC Insecticide is used according to the label directions, which include protective measures.

Workers mixing, loading or applying Pyrifluquinazon 20SC Insecticide, and workers entering recently treated greenhouses can be exposed to pyrifluquinazon residues through direct skin contact and through inhalation. Therefore, the label specifies that anyone mixing, loading and applying Pyrifluquinazon 20SC Insecticide 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 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 in residential and other non-occupational environments

Risks in residential and other non-occupational environments are not of health concern when Pyrifluquinazon 20SC Insecticide is used according to the proposed label directions.

Applications of Pyrifluquinazon 20SC Insecticide will occur within commercial greenhouses only. Therefore, health risks in residential and other non-occupational environments are not of concern.

Health risks to bystanders

Bystander risks are not of health concern when Pyrifluquinazon 20SC Insecticide is used according to the proposed label directions.

Applications of Pyrifluquinazon 20SC Insecticide will occur within greenhouses only. Therefore, health risks to bystanders are not of concern.

Environmental considerations

What happens when Pyrifluquinazon is introduced into the environment?

When pyrifluquinazon is used according to label directions, the risks to the environment are acceptable.

Pyrifluquinazon 20SC Insecticide, containing pyrifluquinazon, will not be released directly into the environment when used on greenhouse food crops and ornamentals. Should pyrifluquinazon enter the environment, it is expected to break down quickly in both soil and water. Pyrifluquinazon exhibits low mobility in soil and low potential to leach through the soil profile to enter ground water.

When pyrifluquinazon is used as a foliar spray for control of pests on greenhouse food crops and ornamentals, beneficial arthropods and bees, which may be used for greenhouse pest management and pollination, could be exposed to spray droplets or residues through contact or oral exposure. While pyrifluquinazon is non-toxic to beneficial arthropods, there is a potential risk to bees. As such, to avoid exposure to bees that may be used in greenhouse production, a label statement is required to avoid application when bees are in the treatment area.

Pyrifluquinazon is toxic to some species of aquatic invertebrates; therefore, label statements prohibiting release of greenhouse effluent into aquatic systems are required.

When pyrifluquinazon is used in accordance with the label directions and the required risk reduction measures are applied, the resulting environmental risk is acceptable.

Value considerations

What is the value of product Pyrifluquinazon 20SC Insecticide?

Pyrifluquinazon 20SC Insecticide is a new active ingredient that provides control of aphids and whitefly in greenhouse lettuce, tomato, eggplant, cucumber and pepper and greenhouse herbaceous and woody ornamentals. Aphids and whitefly are widespread and significant pests of greenhouse crops.

Pyrifluquinazon 20SC Insecticide can aid in resistance management of aphids and whitefly when used in rotation with other insecticides in integrated pest management programs. As pyrifluquinazon stops feeding by insects, it may also aid in reducing the transmission of insect-vectored plant viruses.

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 Pyrifluquinazon Technical and Pyrifluquinazon 20SC Insecticide to address the potential risks identified in this assessment are as follows.

Key risk-reduction measures - Human health

To reduce the potential of workers to pyrifluquinazon through direct skin contact or inhalation of sprays, workers mixing, loading and applying Pyrifluquinazon 20SC Insecticide and 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 statement preventing the use of handheld airblast, mistblowers and foggers is present on the label.

Key risk-reduction measures - Environment

With the following risk reduction measures on the label, the risks are considered acceptable:

• Label statements indicating application should be avoided when bees are in the treatment areas.
• Label statements prohibiting release of greenhouse effluent into aquatic systems.
• Label statement indicating toxicity to aquatic organisms.

Next steps

Before making a final registration decision on pyrifluquinazon and Pyrifluquinazon 20SC Insecticide, Health Canada’s PMRA will consider any comments received from the public in response to this PRD2022-15. Health Canada will accept written comments on this proposal up to 45 days from the date of publication of PRD2022-15. 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 pyrifluquinazon and Pyrifluquinazon 20SC Insecticide (based on the Science Evaluation of PRD2022-15). 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.