ARCHIVED - Memo - Use of Unlabelled Tank Mixes of Commercial Class Pest Control Products Used for Crop Production or Vegetation Management

27 October 2009

1.0 Purpose

This memo serves to clarify the Health Canada Pest Management Regulatory Agency's (PMRA) position regarding the use of unlabelled tank mixes of commercial class pest control products used for crop production or vegetation management.

2.0 Scope

The scope of this memo is limited to tank mixes that fall within the registered use patterns for each tank mix partner, and to registered commercial class pest control products used for crop production, including seed treatments (applied both on-farm and at commercial seed treating facilities), but excluding adjuvants. Commercial class products that are not used for crop production or vegetation management and domestic class products are specifically excluded.

3.0 Background

A tank mix of pest control products may be defined as the simultaneous application of two or more pest control products from the same set of spray nozzles, with each product being referred to as a tank mix partner. Tank mixes may include tank mix partners of the same (for example, herbicide + herbicide) or different types (for example, herbicide + fungicide).

The use of tank mixes is of particular value when it results in a broadening of the spectrum of pests controlled, contributes to resistance management or integrated pest management, or results in a cost- or time-savings to the user.

The majority of registered tank mixes (i.e. those that appear on one or more registered product labels) used for crop production or vegetation management involve the application of two or more tank mix partners, each in accordance with the currently registered use patterns (application rate, application timing, retreatment interval, number of applications per season, pre-harvest interval, etc.) on the respective tank mix partner labels.

4.0 Agency Position

Users of commercial class pest control products used for crop production are permitted to apply unlabelled tank mixes of registered pest control products, subject to the following conditions:

1. Each tank mix partner is registered for use in Canada on the crop of interest, including genetically modified crops.
2. The tank mix only includes an adjuvant when specifically required by one of the tank mix partner labels. If an adjuvant is not required on the label of any tank mix partner, then no adjuvant may be added to the tank mix.
3. The application timings of all tank mix partners are compatible with regards to crop and pest staging.
4. Each tank mix partner is applied in accordance with its registered product label (for example, Directions for Use, Precautions, Buffer Zones, etc.). In cases where information on the tank mix partner labels differs between them, the most restrictive directions must be followed.
5. The tank mix is not specifically excluded or contraindicated on either tank mix partner label.
6. The use of the tank mix provides additional value to the user (for example, increased scope of pests controlled, contributes to resistance management or integrated pest management, cost- or time-savings).

In some cases, tank mixing pest control products can result in reduced biological activity (antagonism-reduced efficacy), or increased biological activity (synergism-increased host injury). This may be acceptable if there are other benefits associated with using the tank mix (for example, cost savings). Anyone who recommends or applies an unlabelled tank mix does so at their own risk and liability as it has not been reviewed by the PMRA. Unlabelled tank mixes that are outside the scope of this memo can be subject to compliance action.

Registrants are permitted to prepare compatibility charts and provide verbal and written guidance regarding the use of unlabelled tank mixes within the scope of this memo to users of such tank mixes. Similar activities by provincial extension specialists and crop advisors are also permitted. Unlabelled tank mixes that fall within the scope of this memo may be promoted, advertised and marketed.

Registrants are permitted to offer for sale two or more registered pest control products in the same packaging if a tank mix of the products falls within the scope of this memo. In this case, the outer common packaging should indicate for which crops the pre-packaged combination of registered products should be used.

Registered product labels within the scope of this memo that currently contain statements that specifically preclude tank mixes that do not appear on the label may be amended to remove these statements at the registrant's discretion.

Tank mixes within the scope of this memo can still be added to registered product labels through existing submission and review processes.

5.0 Questions

Questions concerning the use of unlabelled tank mixes of commercial class pest control products in agriculture should be directed to the PMRA via the Pest Management Information Service.