Registration Decision RD2016-37, 4-Chloroindole-3-Acetic Acid

Pest Management Regulatory Agency
19 December 2016
ISSN: 1925-0940 (PDF version)
Catalogue number: H113-25/2016-37E-PDF (PDF version)

Table of Contents

Registration Decision StatementFootnote 1for 4-chloroindole-3-acetic acid

Health Canada's Pest Management Regulatory Agency (PMRA), under the authority of the Pest Control Products Act and Regulations, is granting full registration for the sale and use of GHA-360 Selective Herbicide Technical and the associated domestic end use products, Wilson Lawn WeedOut(1) Selective Weed Control, Wilson Lawn WeedOut(2) Selective Weed Control, Wilson Lawn WeedOut(1) Battery Powered, Wilson Lawn WeedOut(2) Battery Powered, Wilson Lawn WeedOut Concentrate 10X, Wilson Lawn WeedOut Concentrate 3X, Lawn WeedOut(1) Selective Weed Control Lawn WeedOut(2) Selective Weed Control and the commercial end use product WeedOut PRO, containing the technical grade active ingredient 4‑chloroindole-3-acetic acid, to control small patches or individual broadleaf weeds as a spot treatment in turf.

This decision is consistent with the Proposed Registration Decision PRD2016-27, 4‑chloroindole-3-acetic acid, whichcontains a detailed evaluation of the information submitted in support of this registration. The evaluation found that, under the approved conditions of use, the products have value and do not present an unacceptable risk to human health or the environment. See Appendix I for a summary of comments received during the consultation process as well as the PMRA’s response to these comments.

Other Information

The relevant test data on which the decision is based (as referenced in PRD2016-27, 4‑chloroindole-3-acetic acid) are available for public inspection, upon application, in the PMRA's Reading Room (located in Ottawa). For more information, please contact the Pest Management Information Service by phone (1-800-267-6315) or by e-mail (

Any person may file a notice of objectionFootnote 2 regarding this registration decision within 60 days from the date of publication of this Registration Decision. For more information regarding the basis for objecting (which must be based on scientific grounds), please refer to the Pesticides and Pest Management portion of the Health Canada's website (Request a Reconsideration of Decision) or contact the PMRA's Pest Management Information Service.

Appendix I Comments and Responses


The active ingredient 4-chloroindole-3-acetic acid should not be classified as Group 4 (WWSA) or Group O (HRAC). The active ingredient 4-chloroindole-3-acetic acid is a natural auxin. Group 4 (WWSA) or Group O (HRAC) are called "Synthetic Auxins", therefore, this classification is not appropriate.


The active ingredient, 4-chloroindole-3-acetic acid, may act in a similar manner, in terms of pesticide activity, to the chemical group of synthetic auxins which are classified as Group 4 herbicides according to the Weed Science Society of America (WSSA) and as Group O herbicides according to Herbicide Resistance Action Committee (HRAC). However, this active ingredient has not been officially classified by the WSSA or HRAC.

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