In case you are interested in background information for SDHI fungicides, please follow this link: Information on SDHI fungicides


FRAC Recommendations for SDHI fungicides

 

General Use Recommendations (all Crops)

(Updated in December 2018, changes in bold)

Strategies for the management of SDHI fungicide resistance, in all crops, are based on the statements listed below. These statements serve as a fundamental guide for the development of local resistance management programs.  Resistance management strategies have been designed to be proactive and to prevent or delay the development of resistance to SDHI fungicides.

  • A fundamental principle that must be adhered to when applying resistance management strategies for SDHI fungicides is that:
The SDHI fungicides (benodanil, benzovindiflupyr, bixafen, boscalid, carboxin, fenfuram, fluindapyr, fluopyram, flutolanil, fluxapyroxad, furametpyr, inpyrfluxam, isofetamid, isoflucypram, isopyrazam, mepronil, oxycarboxin, penflufen, penthiopyrad, pydiflumetofen, sedaxane, thifluzamide) are in the same cross-resistance group.

  • Fungicide programs must deliver effective disease management. Apply SDHI fungicide based products at effective rates and intervals according to manufacturers’ recommendations. 
  • Effective disease management is a critical component to delay the build-up of resistant pathogen populations. 
  • The number of applications of SDHI fungicide based products within a total disease management program must be limited.
  • When mixtures are used for SDHI fungicide resistance management, applied as tank mix or as a co-formulated mixture, the mixture partner: should provide satisfactory disease control when used alone on the target disease and must have a different mode of action.
  • Mixtures of two or more SDHI fungicides can be applied to provide good biological efficacy; however, they do not provide an antiresistance strategy and must be treated as a solo SDHI for resistance management. Each application of such a mixture when used in a spray program counts as one SDHI application.
  • SDHI fungicides should be used preventively or at the early stages of disease development. 
  • Please refer to FRAC Recommendations for Mixtures - January 2010 for more information on fungicide mixtures for resistance management.
  • Species can carry different mutations which affect SDHIs. A few mutations can lead to different sensitivities depending on the chemical structure of the active ingredient.
  • As SDHIs are cross-resistant, resistance management must be the same for all SDHIs.
  • All monitoring and guideline related statements refer to the entire group of SDHIs.

  
Specific Recommendations for Fruits and Vegetables

 

Grapes

(Updated in December 2018, no changes)

  • Apply SDHI fungicides according to manufacturers’ recommendations.
  • When mixtures are used for SDHI fungicide resistance management, applied as tank mix or as a co-formulated mixture, the mixture partner should provide satisfactory disease control when used alone on the target disease and must have a different mode of action.
  • Apply a max. of 3 SDHI-containing fungicides per year over all diseases, solo or in mixture with effective mixture partners from different cross-resistance groups but not more than 50% of the total number of applications.
  • A maximum of 4 SDHI fungicide applications may be used where 12 or more fungicide applications are made per crop.
  • If used solo, apply SDHI fungicides in strict alternation with fungicides from a different cross-resistance group.
  • If used in mixture, apply SDHI fungicides in a maximum of 2 consecutive applications.
  • Apply SDHI fungicides preventively.

For SDHI fungicide applications specifically targeted against grey mold, Botrytis cinerea, refer to the table below:

Total number of Botrytis cinerea spray applications per crop 1 2 3 4 5 6 >6
Maximum recommended Solo SDHI fungicide spray (apply in strict alternation) 1 1 1 2 2 2 3
Max. recommended SDHI fungicide sprays in mixture (apply a max. of 2 consecutive applications) 1 1 2 2 2 3 3

Pome fruits

(Updated in Aug. 2017, no changes)

  • Apply SDHI fungicides according to manufacturers’ recommendations.
  • When mixtures are used for SDHI fungicide resistance management, applied as tank mix or as a co-formulated mixture, the mixture partner:
    • should provide satisfactory disease control when used alone on the target disease
    • must have a different mode of action.
  • Apply SDHI fungicides using not more than 2 consecutive applications.
  • Apply SDHI fungicides preventively.

The following spray table shall be used as a guideline irrespective of the targeted disease in pomefruits.

Total number of spray applications per crop 1 2 3 4 5 6 7 8 9 10 11 12 >12
Maximum recommended Solo SDHI fungicide sprays 1 1 1 1 2 2 2 2 2 3 3 3 3
Max. recommended SDHI fungicide sprays in mixture 1 1 2 2 2 3 3 3 3 3 3 4 4

Stone fruits

(Updated in Aug. 2017, no changes)

  • Apply SDHI fungicides according to manufacturers’ recommendations.
  • When mixtures are used for SDHI fungicide resistance management, applied as tank mix or as a co-formulated mixture, the mixture partner and should provide satisfactory disease control when used alone on the target disease and must have a different mode of action.
  • Apply a max. of 3 SDHI-containing fungicides per year over all diseases, solo or in mixture with effective mixture partners.
  • If used solo, apply SDHI fungicides in strict alternation with fungicides from a different cross-resistance group.
  • If used in mixture, apply SDHI fungicides in a maximum of 2 consecutive applications.
  • Apply SDHI fungicides preventively.

Other multi-spray crops (e.g. vegetables, small berries and strawberries)

(Updated in Aug. 2017, no changes)

  • When mixtures are used for SDHI fungicide resistance management, applied as tank mix or as a co-formulated mixture, the mixture partner should provide satisfactory disease control when used alone on the target disease and must have a different mode of action.

The following spray table shall be used as a guideline irrespective of the targeted disease in the crops specified above.

Total number of spray applications per crop 1 2 3 4 5 6 7 8 9 10 11 12 >12
Maximum recommended Solo SDHI fungicide sprays (apply in strict alternation) 1 1 1 1 2 2 2 3 3 3 3 4 *
Max. recommended SDHI fungicide sprays in mixture (apply a mac. of 2 consecutive applications) 1 1 1 2 2 3 3 3 3 3 4 4 *
*When more than 12 fungicide applications are made, observe the following guidelines:

  • When using a SDHI fungicide as a solo product, the number of applications should be no more than 1/3 (33%) of the total number of fungicide applications per season.
  • For programs in which tank mixes or pre-mixes of SDHI fungicides are utilized, the number of SDHI-containing applications should be no more than 1/2 (50%) of the total number of fungicide application per season.
  • In programs where SDHIs are made with both solo products and mixtures, the number of SDHI containing applications should be no more than 1/2 (50%) of the total no. of fungicides applied per season.
  • If used solo, apply SDHI fungicides in strict alternation with fungicides from a different cross-resistance group.
  • If used in mixture, apply SDHI fungicides in a maximum of 2 consecutive applications.

  
Specific Recommendations for Cereals and Soybeans

 

Foliar applications in Cereals

  • Apply SDHI fungicides always in mixtures
  • The mixture partner should provide satisfactory disease control when used alone on the target disease and must have a different mode of action.
  • Apply a maximum of 2 SDHI fungicide containing sprays per cereal crop.
  • Apply the SDHI fungicide preventively or as early as possible in the disease cycle. Do not rely only on the curative potential of SDHI fungicides. 
  • Strongly reduced rate programs including multiple applications must not be used. Refer to manufacturers’ recommendations for rates.

Seed treatment applications in Cereals

SDHIs are and will be used as seed treatment products.  It is FRAC’s objective to protect this fungicide group and integrate all uses into technical recommendations. These recommendations contain a recommendation on seed treatments, including those which have efficacy on foliar pathogens.  These recommendations will be reviewed regularly and supported by monitoring.

  • When an SDHI fungicide is used as a seed treatment on cereals, there should be no implications regarding SDHI FRAC guidelines on the use of foliar SDHI fungicides on the same crop as long as the SDHI seed treatment is directed by rate and efficacy against seed and soil borne diseases or ‘low risk’ foliar pathogens as defined in the FRAC Pathogen Risk List.
  • SDHIs used as a seed treatment in cereals providing foliar efficacy against pathogens with moderate/ high resistance risk count against the total number of SDHI applications.

Soybeans

(Updated in December 2018, no changes)


Species can carry different mutations which affect SDHIs. A few mutations can lead to different sensitivities depending on the chemical structure of the active ingredient.
As all SDHIs are cross-resistant, resistance management must be the same for all SDHIs.  All monitoring and guideline related statements refer to the entire group of SDHIs.

  • Apply SDHI fungicides always in mixtures
  • The mixture partner:
    • should provide satisfactory disease control when used alone on the target disease
    • must have a different mode of action
    • The use of additional, non-cross-resistant modes of action should also be considered (ready-mixtures and tank-mixtures where legally possible)
  • Apply a maximum of 2 SDHI fungicide containing sprays per soybean crop (no soy after soy/ double cropping)
  • Apply the SDHI fungicide preventively or as early as possible in the disease cycle. Do not rely only on the curative properties of SDHIs, or SDHI-containing mixtures

Good agricultural practices must be considered to reduce source of inoculum, disease pressure and resistance risk, e.g. no multiple cropping, implement and respect soybean-free periods, consider partially resistant soybean varieties, reduce the planting window, give preference to early-cycle varieties and endorse the destruction of volunteers.


 

Monitoring Results and Use Recommendations

At the annual meeting, the working group reviews the current year's monitoring results and decides whether they require changes be made to the next year's use recommendations.  The minutes of those meetings are below.

Contact

Dr. Kristin Klappach
Chair

BASF SE
Agricultural Research Station
D-67114 Limburgerhof,
Germany

Tel: +49 62160- 27287
Fax: +49 62160- 6627287
kristin.klappach@basf.com