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You are in: Applicant Advice » Pesticide Approvals » Pesticides Registration » Applicant Guide » The Applicant Guide: Tank-mixes

The Applicant Guide: Tank-mixes

What is a tank-mix?

There are two different types of ‘tank-mix’:

  1. Convenience tank-mixes - The combination by the user of two or more pesticides in the same spray tank to reduce the number of spray operations. A convenience tank-mix can also occur when a product label recommends, in a ‘Compatibility’ section, that the product can be mixed with another product. Such tank-mixes must be shown to be physically and biologically compatible.

The compatibility section of the label may also advise on tank-mixes which are known to be incompatible or on specific mixing instructions to be used with compatible mixes.

  1. Positive tank-mixes - The combination by the user of two or more pesticides in the same spray tank to obtain better pest control than if the products were applied alone.

A positive tank-mix occurs when a product label recommends a mixture to give an enhanced effect when the tank-mix is used (e.g. to control additional pests; to reduce the application rate of one or more of the products).

You cannot include recommendations for tank mixes containing two or more anticholinesterase products unless we have fully assessed the toxicological effects – you should contact us for guidance. Unless there is information to the contrary on the product label, users should not apply ALS herbicides in tank mixture or sequence with other ALS herbicides including sulfonylureas. Further information is available in Regulatory Update 16/2006.

We are currently reviewing our policy on all tank mixes and the way we assess exposure to both the concentrated and diluted products in combination. There may be some changes to our approach in future.

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Convenience tank-mixes

What are the data requirements for the approval of convenience tank-mixes?

If you are applying for the first approved recommendation of a convenience tank-mix for a product that contains an active substance for which no tank-mixes have been previously approved, you must submit data and/or reasoned scientific cases demonstrating that the products can be used safely and efficaciously together in the proposed mixture. These data can be considered under the first application to be considered for the active substance (via the Committee procedure) or any subsequent application for a product containing that active substance (via the Secretariat procedure).

Requirements for subsequent tank-mixtures

Once the first convenience tank-mixture is approved, subsequent convenience tank-mixes for products containing that active substance must be supported by relevant data. We do not need to see these data in full, instead we will accept a Compatibility Assurance Statement (CAS) - a statement certifying that data or evidence is available to demonstrate that the products in the proposed mixture are physically and biologically compatible.

Although we accept CAS's, the underlying data must be available for submission if requested by CRD. Any recommendations made verbally by an approval holder must also be supported by compatibility data.

It is becoming increasingly common for applicants to include general tank-mix compatibility phrases on draft product labels rather than specific lists, such as;

  • ‘For up to date details of compatible tank-mixes contact the manufacturer/distributor’,
  • ‘Product X may be tank-mixed with a variety of plant protection products providing that the application timing is correct for both Product X and the partner(s) in the mixture. For further information on the approval status of mixture partners, consult the manufacturer’
  • ‘Consult manufacturer for details of tank mixes’.

This is acceptable so long as approval has been given for at least one convenience tank-mixture with the active substance.

Notifying CRD of additional convenience tank-mixtures.

CRD must be kept informed of additions to the portfolio of convenience tank-mixtures. However, we do not require a separate application for each addition. Instead we require that each time you submit an application for some other change to the product label, you provide a Compatibility Assurance Statement to confirm that there are compatibility data to support any and all tank mixes being recommended.

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Positive tank-mixes

What are the data requirements for the approval of positive tank-mixes?

In addition to the data listed for convenience tank-mixes, where a positive tank-mix recommendation is being made, then additional efficacy data will be required to support the proposed positive tank-mixes. This also applies to positive tank-mix recommendations made with adjuvants.

The proposed recommendations must be within the approved conditions of use of the product to be included in the positive tank-mix recommendation or you will also need to submit an application, with the appropriate safety data, to amend the approved conditions of use for the product to be included in the positive tank-mix recommendation.

How do I apply for approval of a recommendation for a positive tank-mix?

You may submit an application which only involves the addition of a change to the compatibility section on a product label. Alternatively, you may apply for such a change as part of an application involving other changes to the product.

We will consider a positive tank-mix recommendation either under the first application to be considered for the active substance (via the Committee procedure) or any subsequent application for a product containing that active substance (via the Secretariat procedure).

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How should I specify a tank-mix on my product label?

The products recommended for ‘convenience’ or ‘positive’ tank-mixes on your product label should only be specified in one of the following formats:

  1. Product name (the appropriate MAFF/MAPP number can be included if you wish); or,
  2. MAFF/MAPP number; or,
  3. Active substance name with a list of appropriate MAFF/MAPP numbers; or,
  4. For certain products that are simple salt formulations and contain the same active substance, one formulation is considered to be similar to another in terms of physical and biological characteristics. It is therefore not necessary to test each individual product for compatibility. The following active substances fall under this criteria and products may be referenced as detailed below:
    • For 2,4-D, dichlorprop-P, MCPA, MCPB and mecoprop-P:

    ‘Approved salt formulations containing <active substance>’

    • For products that are simple salt formulations of chlormequat (i.e. not those containing metal chelates or di-1-p-menthene) with or without choline chloride:

    ‘Approved salt formulations containing <active substance>’


    Approved salt formulations containing only chlormequat or chlormequat and choline chloride’

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How should I deal with revoked or commercially withdrawn partner products

Any reference to products that are no longer approved must be removed from the product label. Please see Regulatory Update 16/2009 for further information.

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Further Information


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