Clarifying data requirements for herbicides used in genetically-modified crops

This consultation closed on 28 January 2013.
Consultation period: 
15 October 2012 to 28 January 2013

The APVMA is providing an operational notice to clarify the existing data requirements for a new product or a variation to a product that contains a herbicide active constituent for use in crops that have been genetically-modified for tolerance to these active constituents. For example, this includes, but is not limited to, the use of glyphosate or glufosinate on genetically-modified (GM) herbicide resistant crops such as GM cotton and GM canola.

This is a draft operational notice and stakeholders are invited to provide their comments by the closing date of 28 January 2013.

Operational Notices are developed to inform and consult applicants on proposed changes or additions to the Manual of Requirements and Guidelines (MORAG).

Following consultation, the APVMA:

  • publishes the notices on our website to document the history of changes to requirements; and
  • updates MORAG with the relevant information.

Following consideration of stakeholder comment, relevant changes will be made and the operational notice will be finalised and published on our operational notice page and communication in the Regulatory Update and APVMA Gazette.

View the draft operational notice—Data requirements for herbicides used in genetically-modified crops.

Please send your written submission by email to pesticides@apvma.gov.au or by postal mail to:

Contact Officer
Pesticide Registration
Australian Pesticides and Veterinary Medicines Authority
PO Box 6182
Kingston ACT 2604

Phone: 02 6210 4748
Fax: 02 6210 4776

Email: pesticides@apvma.gov.au

Draft Operational Notice—Data requirements for herbicides used in genetically-modified crops

Products covered: Agricultural chemical products
Purpose: Requirement
Takes effect: Upon publication on APVMA Website

This notice clarifies the existing data requirements for a new product or a variation to a product that contains a herbicide active constituent for use in crops that have been genetically-modified for tolerance to these active constituents. For example, this includes, but is not limited to, the use of glyphosate or glufosinate on genetically-modified (GM) herbicide resistant crops such as GM cotton and GM canola.

Herbicide-resistant GM crop cultivars are designed to be treated repeatedly with the relevant herbicide during an application window that is wider than would be the case in a non-GM crop.

The application of a herbicide to a GM crop may present increased risk in regards to:

  • the efficacy & crop safety or phytotoxicity of the herbicide
  • the resulting residues and
  • potential development of weed resistance.

The applicants for such product registrations, must address these areas of risk via the provision of appropriate data and/or scientific argument. The data requirements for each of the above risks arising from such products are described below.

Efficacy & Crop Safety data

Efficacy and crop safety data must be provided from trials over two growing seasons of the GM crop using the formulation contained in the proposed new or varied product. The trials must be conducted in most recently-released cultivar of the GM crop that contains the relevant trait and as per the contemporary industry practice. Data from trials conducted on GM cultivars with traits previously released and superseded by new ones may not be acceptable.

GM crop cultivars are grown under a wide variety of climatic and edaphic conditions. Therefore, crop safety data must be generated from an appropriately representative number of growing regions. For example, GM cotton crops grown in hot (tropical) conditions are more susceptible to phytotoxicity when treated with certain herbicides. Applicants must provide appropriate data and/or scientific argument on formulation adaptations to deal with such situation-specific crop safety issues.

Residue data

The GM trait conferring tolerance may alter the way in which the herbicide is transformed into a residue. Those transformation pathways may be quite different to the pathways in a conventional crop. OECD Test Guideline 501 clearly describes the situations under which additional metabolism studies need to be conducted for a GM crop to determine if the residue definition resulting from the application of a herbicide to a GM crop is different to the definition that results from use in a conventional crop. OECD Residue Chemistry Test Guidelines (external site) are available on the OECD website.

The requirement for a metabolism study applies for the use of a herbicide product to a new GM crop (including the use of a new gene or possibly a combination of genes in an existing GM crop), rather than to an existing GM crop.

The APVMA requires residues trials for the purposes of setting a Maximum Residue Limit (MRL) to be conducted on most recently-released cultivar of the GM crop that contains the relevant trait. Data from trials conducted on GM cultivars with traits previously released and superseded by new ones are unacceptable. GM crops may modify the behaviour of the chemical degradation pathways which therefore impacts upon the resulting residue profile. These pathways may respond differently to variations in formulation, application timings and rates when compared to those of conventional crops. The arguments that would be made for a conventional crop do not apply to GM crops and the over-the-top use of a herbicide. Assessment of residues data for glyphosate and glufosinate have established that the differences in residues concentrations of a herbicide used in a GM crop when compared to a conventional crop can be significant and residues data will be required to support these uses.

The requirement for bridging or confirmatory data applies to the use of an existing herbicide to any new GM crop (or new use pattern for an existing herbicide), as well as use of an existing herbicide to an existing GM crop (or existing use pattern for a herbicide in a GM crop). Comparability of formulation, application timing and use rates are not considered sufficient grounds on which to make a determination on the adequacy of an existing MRL. Scientific argument that may be provided for a conventional crop is not acceptable for a GM crop owing to possible variations in the response of the GM plant to the herbicide.

Residue Guideline 24 (RGL 24) outlines the numbers of trials that are required for different crops for the purposes of setting an MRL.

As with efficacy & crop safety trials, residues trials should be conducted on appropriate cultivars in locations that are representative of the main growing regions in Australia. The maximum use pattern (as per label) must be trialled and samples collected in accordance with the guidance provided in RGL 24. If the directions for use specify a variety of application timings, each trial must include a number of treatment regimens to ensure that the maximum residue scenario is addressed.

Please contact the contact the APVMA and discuss the trial protocol if unsure about the required number of confirmatory trials. As current GM crops are considered to be major crops, GLP requirements apply.

Resistance Management Plan

The repeated application of a herbicide increases the potential for weeds to development resistance to the active constituent/s contained in the product/s. Applicants are therefore required to provide an appropriate resistance management strategy that provides users with:

  1. adequate instructions regarding the need for preventative resistance management on the product label.
  2. a specific resistance management plan (RMP) that is acceptable to the relevant grower organisation as signified by written approval from a duly designated/authorised officer of that organisation. Where a specific grower organisation is not identifiable or does not exist for the particular GM crop, the APVMA will consider imposing conditions on the registrant to convene a group of suitable persons for the purposes of consultation on matters of resistance management. Typically, for products used on GM cotton, approval of the CMP/RMP is required from the Transgenic and Insect Management Strategies (TIMS) committee of the ACGRA.

Conditions of registration

Where appropriate, the APVMA will impose specific conditions of registration that are designed to enforce the practice of preventative weed resistance management by users of the chemical product and to place obligations on registrants regarding the conduct of weed audits, reporting of weed escapes identified from such audits and taking follow up action to deal with weed escapes. These conditions are necessary as the use pattern is recognised as increasing the potential for the development of weed resistance to the active constituent.

Applicants should also refer to the applicable requirements and guidelines in the Agricultural Manual Of Requirements And Guidelines (Ag MORAG) in regards other relevant legislative criteria relating to public, occupational and environmental health and safety. As the circumstances associated with chemical applications to GM crops are significantly different compared to conventional crops, it would be beneficial to discuss requirements with the APVMA prior to commencing trials for data generation or lodging the registration application.

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