Special Review Decision SRD2021-04, Special Review Decision: Thiamethoxam Risk to Aquatic Invertebrates

Pest Management Regulatory Agency
31 March 2021
ISSN: 2561-6269 (PDF version)
Catalogue number: H113-17/2021-4E-PDF (PDF version)

Summary

To obtain a full copy of Special Review Decision SRD2021-04, Special Review Decision: Thiamethoxam Risk to Aquatic Invertebrates please contact our publications office.

Health Canada’s Pest Management Regulatory Agency will host a webinar to provide an overview of the decisions for clothianidin and thiamethoxam. For more information and to register, select the following link: Health Canada webinar

Should you require further information please contact the Pest Management Information Service.

Table of contents

Special review decision

Pursuant to subsection 17(1) of the Pest Control Products Act, Health Canada’s Pest Management Regulatory Agency (PMRA) conducted a special review of all agricultural, greenhouse and ornamental uses for registered pest control products containing thiamethoxam. The decision to conduct the special review was based on a preliminary analysis of available information on the concentration and frequency of detections of thiamethoxam in the aquatic environment. The aspect of concern for this review is to assess potential risk to aquatic invertebrates exposed to thiamethoxam applied as a seed, foliar or soil treatment.

Health Canada evaluated the aspect of concern that prompted the special review in accordance with subsection 18(4) of the Pest Control Products Act. The proposed special review decision was published for consultation in Proposed Special Review Decision (PSRD2018-02), Special Review of Thiamethoxam Risk to Aquatic Invertebrates: Proposed Decision for Consultation.Footnote 1 Since the publication of PSRD2018-02 on 15 August 2018, a significant number of comments were received during the consultation period. In addition, extensive information obtained from published literature, as well as data received from registrants and environmental monitoring networksFootnote 2 was also considered.

In addition, during the consultation period, Health Canada issued a final re-evaluation decision examining the effects of thiamethoxam on pollinators Re-evaluation Decision RVD2019-04, Thiamethoxam and Its Associated End-use Products: Pollinator Re-evaluation. Final Decision. This special review decision takes into consideration the additional mitigation measures put in place as a result of the pollinator re-evaluation. Health Canada has completed the special review for thiamethoxam, and this final special review decision has resulted in changes to the proposed regulatory decision as described in PSRD2018-02.

A reference list of information used as the basis for the proposed special review decision is included in PSRD2018-02. Further information used in the special review decision is listed in Appendix IX of Special Review Decision: Thiamethoxam Risk to Aquatic Invertebrates (SRD2021-04). Therefore, the complete reference list of all information used in this final special review decision includes both the information set out in the list of references of the PSRD2018‑02 and the information set out in Appendix IX of SRD2021-04.

This document presents the final regulatory decisionFootnote 3 for the special review of thiamethoxam, including the required risk mitigation measures to protect aquatic invertebrates. All pest control products containing thiamethoxam that are registered in Canada for agricultural, greenhouse and ornamental uses are subject to this special review decision (see Appendix I). Appendix II lists all of the registered uses of Commercial Class end-use products containing thiamethoxam that were subject to this special review, taking into consideration the required use restrictions identified in RVD2019-04. Appendix III of SRD2021-04 summarizes the comments received during the consultation period and provides Health Canada’s response to these comments. All of the data that were used as the basis for the proposed special review decision are published in PSRD2018‑02. Additional data used in the final special review decision, including data received during the consultation period, are listed in Appendix IV for toxicity information and in Appendix VII of SRD2021-04 for monitoring information.

Under the authority of the Pest Control Products Act, Health Canada has determined that continued registration of products containing thiamethoxam is acceptable with additional risk mitigation measures (that is, with changes to the conditions of registration). An evaluation of available scientific information found that some uses of thiamethoxam products meet current standards for protection of the environment when used according to revised label directions, which include mitigation measures. Certain uses of thiamethoxam are cancelled as risks to aquatic invertebrates were not shown to be acceptable. Label amendments, as summarized below and listed in Appendix VIII of SRD2021-04, are required.

Outcome of science evaluation

The environmental risk assessment took into consideration revisions to thiamethoxam uses as outlined in RVD2019-04, scientific comments received on study interpretations during consultation of PSRD2018-02, newly published relevant toxicity data and additional water monitoring data. Based on these data it was determined that the risks to aquatic invertebrates resulting from chronic exposure following application of thiamethoxam under certain currently registered conditions are acceptable. For uses where the risks were not shown to be acceptable, mitigation measures are required to minimize exposure to aquatic invertebrates which include changes to the use pattern or cancellation in cases when other mitigation options were not considered viable. In addition to the prescribed mitigation measures, label amendments including the addition of best management practices and label statements informing users of the toxicity to aquatic organisms are required. When thiamethoxam is used in accordance with these new risk reduction measures, the reduced environmental exposure is sufficient to address concerns and risks are acceptable.

Regulatory decision for thiamethoxam

Health Canada has completed the special review of thiamethoxam’s risk to aquatic invertebrates. Following an evaluation of the aspect of concern, under the authority of the Pest Control Products Act, Health Canada has determined that, with additional risk mitigation measures, continued registration of products containing thiamethoxam is acceptable. An evaluation of available scientific information found that some uses of thiamethoxam products meet current standards for protection of aquatic invertebrate communities when used according to the revised conditions of registration, which include required amendments to label directions. Label amendments, as summarized below and listed in Appendix VIII of SRD2021-04, are required for all end-use products. Certain uses of thiamethoxam are cancelled as risks to aquatic invertebrates were not shown to be acceptable.

Risk mitigation measures to protect aquatic invertebrates

Registered pesticide product labels include specific directions for use. Directions include risk mitigation measures to protect human health and the environment and must be followed by law. The required amendments, including any revised/updated label statements and/or mitigation measures as a result of this Special Review Decision, are summarized below. Refer to Appendix VIII of SRD2021-04 (Label Amendments).

In order to protect aquatic invertebrate communities, Health Canada is cancelling the following uses of thiamethoxam:

Health Canada is changing the conditions of use of thiamethoxam for the following crops:

Next steps

To comply with this decision, the required amendments (mitigation measures and label updates) must be implemented on all product labels no later than 24 months after the publication date of this special review decision (SRD2021-04). The risks identified are not considered imminent and serious because they are not expected to cause irreversible harm over this phase-out period. Potential effects include reduced aquatic insect abundance. Affected populations have the potential to recover following implementation of the additional restrictions which will reduce overall exposure. Accordingly, both registrants and retailers will have up to 24 months from the date of this decision document to transition to selling the product with the newly amended labels. This approach is consistent with Health Canada’s current policy and practice with respect to phase out of uses as a result of a re-evaluation (Regulatory Directive DIR2018-01, Policy on Cancellations and Amendments Following Re-evaluation and Special Review).

Similarly, users will also have the same 24-month period from the date of SRD2021-04 to transition to using the newly amended labels, which will be available on the Public Registry.

Refer to Appendix I for details on specific products impacted by this decision.

Other information

Any person may file a notice of objectionFootnote 4 regarding this decision on thiamethoxam within 60 days from the date of publication of this special review decision. For more information regarding the basis for objecting (which must be based on scientific grounds), please refer to the Pesticides section of the Canada.ca website (Request a Reconsideration of Decision) or contact the PMRA’s Pest Management Information Service by phone (1-800-267-6315) or by e-mail (hc.pmra-info-arla.sc@canada.ca).

The relevant confidential test data on which the decision is based (as referenced in PSRD2018‑02 and Appendix IX of SRD2021-04) are available for public inspection, upon application, in the PMRA’s Reading Room. For more information, please contact the PMRA’s Pest Management Information Service.

Appendix I Registered products containing thiamethoxam in Canada that are subject to this special review decision

Table 1 Registered products containing thiamethoxam in Canada requiring (label) amendmentsTable 1 Footnote 1
Registration number Marketing class Registrant Product name Formulation type Active ingredient

26637

Commercial

Syngenta Canada Inc.

Helix Liquid Seed Treatment

Suspension

  • Thiamethoxam 10.3%;
  • metalaxyl-M and S isomer 0.39%;
  • fludioxonil 0.13%;
  • difenoconazole 1.24%

27045

Commercial

Cruiser 5FS Seed Treatment

Suspension

  • Thiamethoxam 47.6%

28407

Commercial

Actara 240SC Insecticide

Suspension

  • Thiamethoxam 240 g/L

28408

Commercial

Actara 25WG Insecticide

Wettable granules

  • Thiamethoxam 25.0%

28821

Commercial

Cruiser Maxx Beans Seed Treatment

Suspension

  • Thiamethoxam 22.6%;
  • metalaxyl-M and S isomer 1.70%;
  • fludioxonil 1.12%

30404

Commercial

Endigo Insecticide

Suspension

  • Thiamethoxam 141 g/L;
  • lambda-cyhalothrin 106 g/L

30436

Commercial

Cruiser Maxx Vibrance Cereals Seed Treatment

Suspension

  • Thiamethoxam 30.7 g/L;
  • sedaxane 8.0 g/L;
  • metalaxyl-M and S isomer 9.5 g/L;
  • difenoconazole 36.9 g/L

30723

Commercial

Flagship Insecticide

Wettable granules

  • Thiamethoxam 25%

30900

Commercial

Minecto Duo 40WG

Wettable granules

  • Thiamethoxam 20%;
  • cyantraniliprole 20%

30901

Commercial

Mainspring X Insecticide

Wettable granules

  • Thiamethoxam 20%;
  • cyantraniliprole 20%

31024

Commercial

Cruiser Maxx Potato Extreme

Suspension

  • Thiamethoxam 250 g/L;
  • fludioxonil 62.5 g/L;
  • difenoconazole 123 g/L

31453

Commercial

Cruiser Vibrance Quattro

Suspension

  • Thiamethoxam 61.5 g/L
  • Difenoconazole 36.9 g/L
  • Metalaxyl-M and S-Isomer 9.2 g/L
  • Sedaxane 15.4 g/L
  • Fludioxonil 7.7 g/L

31454

Commercial

Helix Vibrance

Suspension

  • Thiamethoxam 269 g/L
  • Difenoconazole 16 g/L
  • Metalaxyl-M and S-Isomer 5 g/L
  • Sedaxane 3.4 g/L
  • Fludioxonil 1.7 g/L
Table 1 Footnote 1

as of 19 January 2021, excluding discontinued products or products with a submission for discontinuation.

Table 1 Return to footnote 1 referrer

Table 2 Registered products containing thiamethoxam in Canada that do not require (label) amendmentsTable 2 Footnote 1
Registration number Marketing class Registrant Product name Formulation type Active ingredient (%, g/L)
26665 Technical Syngenta Canada Inc. Thiamethoxam Technical Dust or powder (solid) 99.1%
Table 2 Footnote 1

as of 19 January 2021, excluding discontinued products or products with a submission for discontinuation

Table 2 Return to footnote 1 referrer

Appendix II Registered commercial class uses of thiamethoxam in Canada as of 31 July 2020 that are subject to this special review

Site(s)Appendix 2 Footnote 1 Pest(s) Formulation type Application methods and equipment Application rateAppendix 2 Footnote 2 Maximum number of applications per year Minimum application interval(day s) Change in application timing based on pollinator risk (RVD2019-06)Appendix 2 Footnote 3
Use-site Category 5 – Greenhouse Food Crops

Greenhouse Peppers

Pepper weevil

Wettable granules

Ground application: foliar spray

  • 3.5 g a.i./100 L
  • 70 g a.i./ha

12/year – 3 per crop cycle

7

-
Use-site Category 6 – Greenhouse Non-Food Crops

Greenhouse coniferous evergreens, greenhouse ornamental grasses, greenhouse grown cut flowers and indoor potted plants

Aphids, dipteran leafminers, mealybugs, soft scales, thrips whiteflies

Wettable granules

Ground application: foliar spray

  • 7.5 - 15 g a.i./100L
  • 75 - 150 g a.i./ha

8/year -2 per crop cycle

14

-

Aphids, dipteran leafminers, mealybugs, soft scales, fungus gnats, root aphids, whiteflies, thrips

Ground application: soil drench

  • 10 - 15 g a.i./100L
  • 200 - 300 g a.i./ha/crop cycle

4/year -1 per crop cycle

Not applicable

Use-site Category 10 – Seed and Plant Propagation Materials Food and Feed

Barley

Wireworms, European chafer

Suspension

Commercial and on farm seed treatment equipment

  • 10 - 30 g a.i./100 kg seed
  • 6.7 - 36.3 g a.i./ha

1

Not applicable

-

Wheat

  • 10 - 30 g a.i./100 kg seed
  • 6.7 – 52.5 g a.i./ha}

Oats

Wireworms

  • 10 - 20 g a.i./100 kg seed
  • 5.4 - 22.8 g a.i./ha

Buckwheat

  • 10 - 30 g a.i./100 kg seed
  • 3.9 - 24.3 g a.i./ha

Millet

  • 10 - 30 g a.i./100 kg seed
  • 0.55 - 6.7 g a.i./ha

Sorghum

  • 10 to 30 g a.i./100 kg seed
  • 0.9 - 4.5 g a.i./ha

Rye

  • 10 to 30 g a.i./100 kg seed
  • 6.2 – 20.2 g a.i./ha

Triticale

  • 10 to 30 g a.i./100 kg seed,
  • 8.1 - 63.0 g a.i./ha

Corn (Field, seed, sweet, popcorn)

 

European chafer, wireworm

Suspension

Commercial seed treatment equipment

  • 50 g a.i./100 kg seed
  • field 7.9 – 11.8 g a.i./ha
  • popcorn 8.5 – 12.4 g a.i./ha
  • sweet 5.3-7.6 g a.i./ha

1

Not applicable

Seedcorn maggot, corn flea beetle

  • 50 - 100 g a.i./100 kg seed
  • field 7.9 -23.7 g a.i./ha
  • popcorn 8.5 - 24.8 g a.i./ha
  • sweet 5.3-15.1 g a.i./ha

Corn rootworm

  • 500 g a.i./100 kg seed
  • field 78.8 –118.3 g a.i./ha
  • popcorn 85.3 - 123.8 g a.i./ha
  • sweet 52.5-75.6 g a.i./ha

Corn (Field, seed, sweet, popcorn)- for export only, not planted in Canada

Corn rootworm

Suspension

Not applicable

  • 200 g a.i./100 kg seed

Not applicable

Not applicable

-

Bean (dry)

Potato leafhopper, seedcorn maggot

Suspension

Commercial seed treatment equipment

  • 30 - 50 g a.i. /100 kg seed
  • 9.6 - 41.5g a.i./ha

1

Not applicable

-

Wireworm

  • 50 g a.i. /100 kg seed
  • 41.5 g a.i./ha

Chickpeas

Wireworm

Suspension

Commercial and on farm seed treatment equipment

  • 10 - 30 g a.i./100 kg seed
  • 9.0 - 46.5 g a.i./ha

1

Not applicable

Faba bean

  • 10 - 30 g a.i./100 kg seed
  • 26.6 – 111.6 g a.i./ha

Lentils

  • 10 - 30 g a.i./100 kg seed
  • 4.5 – 27.0 g a.i./ha

Lupins

  • 10 - 30 g a.i./100 kg seed
  • 15.7 – 50.4 g a.i./ha

Dry peas

  • 10 - 30 g a.i./100 kg seed
  • 10.4 -83.1 g a.i./ha

Faba bean

Pea leaf weevil

Suspension

Commercial and on farm seed treatment equipment

  • 30 g a.i./100 kg seed
  • 79.8 – 111.6 g a.i./ha

1

Not applicable

Pea (dry)

  • 30 - 50 g a.i./100 kg seed
  • 31.2 – 138.5 a.i./ha

Succulent bean

Potato leafhopper, seedcorn maggot

Suspension

Commercial seed treatment equipment

  • 30 - 50 g a.i./100 kg seed
  • 22.5 – 50.0 g a.i./ha

1

Not applicable

Wireworm, soybean aphid

  • 50 g a.i./100 kg seed
  • 37.5 – 50.0 g a.i./ha

Succulent pea

Potato leafhopper, seedcorn maggot

  • 30 - 50 g a.i./100 kg seed
  • 30-150 g a.i./ha

Wireworm, soybean aphid

  • 50 g a.i./100 kg seed
  • 50-150 g a.i./ha}

Pea leaf weevil

  • 30 - 50 g a.i./100 kg seed
  • 30 – 150 g a.i./ha

Soybean

Seedcorn maggot

Suspension

Commercial seed treatment equipment

  • 30 - 50.8 g a.i./100 kg seed
  • 17.1 - 63.0 g a.i./ha

1

Not applicable

Bean leaf beetle, European chafer, soybean aphid, wireworm

  • 50.8 g a.i./100 kg seed
  • 28.5 – 64.g a.i./ha

Canola, rapeseed

Flea beetles

Suspension

Commercial seed treatment equipment

  • 199.4 - 403.5 g a.i./100 kg seed
  • 8.0 - 32.3 g a.i./ha

1

Not applicable

Mustard

  • 199.4 - 403.5 g a.i./100 kg seed
  • 9.0 - 45.2 g a.i./ha

Potato

Aphids, Colorado potato beetle,
potato leafhopper

Suspension

Seed piece treatment equipment: slurry

  • 1.9 - 5.86 g a.i./100 kg seed
  • 91.2 or 117 g a.i./ha

1

Not applicable

Sunflowers

Wireworm

Suspension

Seeds are not treated in Canada but are imported pre-treated with thiamethoxam.

  • 0.25 mg a.i./seed
  • 4.4 - 27.5 g a.i/ha

1

Not applicable

-

Sugar beet

Wireworm, sugar beet root maggot

Suspension

Commercial seed treatment equipment

  • 30 - 60 g a.i./100,000 seeds
  • 19.5 – 58.7 g a.i./ha

1

Not applicable

Crop Group 9 Cucurbit Vegetables

Cucumber beetle

Suspension

Seeds are not treated in Canada but are imported pre-treated with thiamethoxam.

  • 0.25 - 0.75 mg a.i./seed
  • cucumber: 4.6 – 20.8 g a.i./ha
  • pumpkin/squash 0.56 – 8.3 g a.i./ha

1

Not applicable

Use-site Category 13 – Terrestrial Feed Crops & Use-site Category 14 – Terrestrial Food Crops

Potato

Aphids, Colorado potato beetle, potato leafhopper

Suspension

Ground and aerial application: foliar spray

  • 26.2 g a.i./ha

2

7

-

Water dispersible granule

Suspension

Ground application: soil drench and in-furrow

  • 0.82 - 1.06 g a.i./100m of row
  • 37.9 - 140 g a.i./ha

1

Not applicable

Aphids, Colorado potato beetle,
flea beetles, potato leafhopper

Wettable granule

  • 0.66 - 3.2 g a.i./100m of row
  • 88 - 140 g a.i./ha
Use-site Category 14 Only – Terrestrial Food Crops

Bean (dry) (Phaseolus spp., Lupinus spp., Vigna spp., dry fava beans, dry lablab beans and chickpeas, soybean)

Bean leaf beetle, soybean aphid

Suspension

Ground and aerial application: foliar spray

  • 25.38 g a.i./ha

3

7

Do not apply pre-bloom or during bloom (Do not apply until after stage R3.5 (petal fall).

Celeriac

Tarnished plant bug

Water dispersible granule

Ground application: foliar spray

  • 52.5 - 70 g a.i./ha

2

Not stated

-

Crop Group 1B and 1C Root vegetables

Aphids, Aster leafhopper

Water dispersible granule

Ground application: foliar spray

  • 26.25 g a.i./ha

2

7

Crop Group 4 Leafy vegetables

Aphids

Water dispersible granule

Ground application: foliar spray

  • 26.25 g a.i./ha

2

7

Tarnished plant bug

  • 52.5 g a.i./ha

1

Not applicable

Aphids, dipteran leafminers, leafhoppers, cabbage looper, flea beetle, beet armyworm, corn earworm, fall armyworm

Wettable granule

Ground application: soil drench (surface banding) and in-furrow

  • 0.23 - 4.5 g a.i./100m of row
  • 150 g a.i./ha

Aphids, leafhoppers, dipteran leafminers, flea beetle

Suspension

  • 90 - 150 g a.i./ha

Crop Group 5 Brassica vegetables

Aphids, dipteran leafminers, flea beetles, cabbage looper, diamondback moth, imported cabbageworm thrips, beet armyworm, corn earworm, fall armyworm, yellowstripped armyworm

Wettable granule

Ground application: soil drench (surface banding) and in-furrow

  • 0.23 - 4.5 g a.i./100m of row
  • 150 g a.i./ha

1

Not applicable

Aphids, flea beetle

Suspension

  • 90 - 150 g a.i./ha

Crop Group 8 Fruiting vegetables

Aphids

Water dispersible granule

Ground application: foliar spray

  • 26.25 g a.i./ha

2

7

Do not apply pre-bloom or during bloom

(Do not apply until petal fall).

Tarnished plant bug, stink bug

  • 26.25 - 52.5 g a.i./ha

Brown marmorated stink bug

  • 52.5 g a.i./ha

Pepper

Pepper weevil

  • 70 g a.i./ha

Crop Group 13-07A Cane berries

Black vine weevil, obscure root weevil

Water dispersible granule

Ground application: foliar spray

  • 52.5 - 70 g a.i./ha

2

7

Do not apply pre-bloom or during bloom (Do not apply until petal fall). When applying after petal fall, renovation of woody plants (cutting back old growth) must occur after harvest and before the next season's bloom.

Crop Group 13-07B Bush berries

Black vine weevil, obscure root weevil

Water dispersible granule

Ground application: foliar spray

  • 52.5 - 70 g a.i./ha

2

7

Brown marmorated stink bug

  • 70 g a.i./ha

Crop Group 13-07G Low growing Berries

Adult black vine weevil, cranberry weevil

Water dispersible granule

Ground application: foliar spray

  • 52.5 - 70 g a.i./ha

2

7

Use-site Category 27 - Ornamentals Outdoor

Outdoor ornamentals (coniferous evergreens and Ornamental grasses only)

Aphids, black vine weevil, dipteran leafminers, lace bugs, leafhoppers, mealybugs, psyllids, soft scales, thrips

Wettable granules

Ground application: foliar spray

  • 7.5 - 15 g a.i./100L
  • 75 - 150 g a.i./ha

1 at high rate or 2 at low rate

14

-

Black vine weevil

Water dispersible granule

Ground application: foliar spray

  • 2.63 - 3.5 g a.i./100L

2

7

Aphids, leafhoppers

  • 26.25 g a.i./ha

Tarnished plant bug

  • 52.5 - 70 g a.i./ha

Outdoor nurseries and landscape (coniferous

evergreens and ornamental grasses only)

Brown marmorated stink bug

Water dispersible granule

Ground application: foliar spray

  • 70 g a.i./ha

1

Not applicable

Appendix 2 Footnote 1

Crop groups are identified as listed on the end use product labels and may not be identical to the crop groups listed on the Health Canada Residue Chemistry Crop Groups website: http://hc-sc.gc.ca/cps-spc/pest/part/protect-proteger/food-nourriture/rccg-gcpcr-eng.php

Appendix 2 Return to footnote 1 referrer

Appendix 2 Footnote 2

g = gram; a.i. = active ingredient; L = litre; ha = hectare; kg = kilogram

Appendix 2 Return to footnote 2 referrer

Appendix 2 Footnote 3

All foliar applications include the following pollinator restriction: Do not apply during bloom.

Appendix 2 Return to footnote 3 referrer

Footnote 1

“Consultation statement” as required by subsection 28(2) of the Pest Control Products Act.

Return to footnote 1 referrer

Footnote 2

For further details on the environmental monitoring network please refer to Section 1.5.1 of the Response to Comments.

Return to footnote 2 referrer

Footnote 3

“Decision statement” as required by subsection 28(5) of the Pest Control Products Act.

Return to footnote 3 referrer

Footnote 4

As per subsection 35(1) of the Pest Control Products Act.

Return to footnote 4 referrer

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