Proposed Registration Decision PRD2023-05, DeltaGard SC Insecticide, containing deltamethrin

• Pest Management Regulatory Agency
• 27 June 2023
• ISSN: 1925-0886 (PDF version)
• Catalogue number: H113-9/2023-5E-PDF (PDF version)

Summary

Table of contents

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

Proposed registration decision for DeltaGard SC 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 DeltaGard SC Insecticide, containing the technical grade active ingredient deltamethrin, to control box tree moth on outdoor-grown boxwood. 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.

Deltamethrin Technical Insecticide (Registration Number 18092) is currently registered in Canada for use on greenhouse ornamentals, greenhouse food crops, industrial oilseed crops, terrestrial feed and food crops, roadsides, shelterbelts, indoor and outdoor surfaces of agricultural buildings and structures, and turf for the control of numerous insect pests and to control adult mosquitoes in residential and recreational areas. For details, see PRD2019-07 and RD2019-15, Deltamethrin and Annihilator PolyZone; PRVD2015-07, Deltamethrin; and RVD2018-27, Deltamethrin and its associated End-use Products. The use of deltamethrin on outdoor ornamentals is a new use for this active ingredient.

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

This summary describes the key points of the evaluation, while the Science evaluation of Proposed Registration Decision PRD2023-05, DeltaGard SC Insecticide, containing deltamethrin provides detailed technical information on the human health, environmental and value assessments of DeltaGard SC Insecticide, containing deltamethrin, when applied to outdoor ornamentals.

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 Canada.ca.

Before making a final registration decision on deltamethrin, DeltaGard SC, 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 deltamethrin, DeltaGard SC, 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 PRD2023-05.

What is deltamethrin?

Deltamethrin is the active ingredient in the commercial class product DeltaGard SC Insecticide, which is used to kill various insect pests on turf, greenhouse floriculture crops, and outdoor-grown boxwood. Deltamethrin is a broad-spectrum synthetic pyrethroid insecticide which affects the insect nervous system causing paralysis and death.

Health considerations

Can approved uses of deltagard SC insecticide affect human health?

DeltaGard SC Insecticide, containing deltamethrin, is unlikely to affect your health when used according to label directions.

Potential exposure to DeltaGard SC Insecticide may occur when handling and applying the product, or through worker or bystander exposure following application. 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). As such, sex and gender are taken into account in the risk assessment. Only uses for which the exposure is well below dose 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 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.

The end-use product DeltaGard SC Insecticide is considered to be of low acute toxicity via the oral, dermal, and inhalation routes of exposure and minimally irritating to the eyes and skin. An allergic skin reaction may occur following repeated dermal exposure, and consequently, the hazard statement "POTENTIAL SKIN SENSITIZER" is required on the product 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 deltamethrin to cause neurotoxicity, immunotoxicity, chronic toxicity, cancer, reproductive and developmental toxicity, and various other effects. The most sensitive endpoint used for risk assessment was neurotoxicity, characterized by a reduced reflex response in young animals. There is some indication that the young may be more sensitive than the adult animal; this sensitivity may reflect age-dependent differences such as the maturation of key metabolic processes.

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 at which these effects occurred in animal tests.

Risks in residential and other non-occupational environments

Non-occupational risks are not of concern when DeltaGard SC is used according to label directions.

As there is no potential exposure to homeowners mixing, loading, and applying deltamethrin, only a residential postapplication risk assessment was required. Residential postapplication exposure may occur from the commercial application of DeltaGard SC to boxwood.

Potential exposure to the public is expected to occur primarily by the dermal route when coming into contact with treated foliage. Residential postapplication activities met the target dermal margin of exposure (MOE) for all populations and are not of concern.

Occupational risks from handling DeltaGard SC

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

Workers who mix, load or apply DeltaGard SC as well as postapplication workers entering treated areas can be exposed to deltamethrin residues through direct skin contact and through inhalation. Therefore, the label specifies that anyone mixing/loading and applying DeltaGard SC must wear a long-sleeved shirt, long pants, chemical-resistant gloves, socks and shoes during mixing, loading, application, clean-up and repair. In addition, the label permits the use of handheld mist blowers/airblast equipment. Workers applying DeltaGard SC using handheld mist blower/airblast equipment must wear chemical-resistant coveralls with a chemical-resistant hood over long-sleeved shirt, long pants, chemical-resistant gloves, socks, chemical-resistant footwear and a respirator with a NIOSH-approved organic-vapour-removing cartridge with a prefilter approved for pesticides OR a NIOSH-approved canister approved for pesticides. The label also requires that workers not enter treated fields for twelve (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 health risk to these individuals from exposure to DeltaGard SC is not a concern.

As application is limited to agricultural crops only when there is low risk of drift to areas of human habitation or activity, bystander exposure is considered negligible. Therefore, health risks to bystanders are not of concern.

Environmental considerations

What happens when deltamethrin is introduced into the environment?

Environmental risks associated with the uses of deltamethrin, and its associated end-use product DeltaGard SC Insecticide, are acceptable when used according to label directions.

Deltamethrin was found to be toxic to bees, beneficial insects, mammals and aquatic organisms. The current product label for DeltaGard SC Insecticide has statements to reduce harmful effects on bees, beneficial insects, mammals and aquatic organisms, including spray buffer zones to protect non-target terrestrial and aquatic habitats.

The new use to control the box tree moth on outdoor-grown boxwood is within the currently registered application rate for the active ingredient deltamethrin, however, the use of airblast equipment is new to the DeltaGard SC Insecticide label. As such, spray buffer zones specific to the use of airblast application methods are required on the DeltaGard SC Insecticide.

Value considerations

What is the value of DeltaGard SC?

DeltaGard SC Insecticide controls the invasive species box tree moth (Cydalia perspectalis) on outdoor-grown boxwood.

Box tree moth is an invasive species, which only feeds on boxwood, causing significant damage which can result in unmarketability and lead to plant mortality. Boxwood is a slow-growing and high-value ornamental crop. Box tree moth is a major threat to the Canadian boxwood nursery industry and the export market for Canadian-grown boxwood.

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 DeltaGard SC to address the potential risks identified in this assessment are as follows.

Key risk-reduction measures - Human health

Because there is potential for users' skin to come into direct contact with deltamethrin residues, anyone mixing/loading and applying DeltaGard SC (except for applicators using handheld mist blower/airblast equipment) must wear a long-sleeved shirt, long pants, chemical-resistant gloves, socks and shoes during mixing, loading, application, clean-up and repair. Workers applying DeltaGard SC using handheld mist blower/airblast equipment must wear chemical-resistant coveralls with a chemical-resistant hood over long-sleeved shirt, long pants, chemical-resistant gloves, socks, chemical-resistant footwear and a respirator with a NIOSH-approved organic-vapour-removing cartridge with a prefilter approved for pesticides OR a NIOSH-approved canister approved for pesticides.

In addition, standard label statements to protect against drift during application are on the label. For postapplication re-entry activities, workers must not enter into treated areas during the restricted-entry interval (REI) of 12 hours.

Key risk-reduction measures - Environment

• An update to the existing label language to mitigate risks to pollinators is required to bring it in line with current risk mitigating measures.
• Spray buffer zones for non-target aquatic and terrestrial habitats are required for the airblast application method.

Next steps

Before making a final registration decision on DeltaGard SC Insecticide, containing deltamethrin, Health Canada's PMRA will consider any comments received from the public in response to PRD2023-05. Health Canada will accept written comments on this proposal up to 45 days from the date of publication of PRD2023-05. 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 DeltaGard SC Insecticide, containing deltamethrin (based on the Science evaluation of PRD2023-05). 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.