SDHI fungicides (MOA Group 7) are at risk in New Zealand as pathogen sensitivity to them declines. This Update provides user guidelines to help maintain the efficacy of this important fungicide group.
Key points
- Limit the number of fungicide applications to one or two per season as per the statutory requirements stated on the product label.
- Apply SDHIs in mixtures that contain at least one other fungicide from an alternative mode-of-action (MOA) group that has comparable efficacy against the target pathogen.
- Alternate SDHI active ingredients both within and between seasons.
- If you use one SDHI per season, use a different one the following season (e.g. benzovindiflupyr in Year 1 and isoflucpyram or fluxapyroxad in Year 2).
- If you use two SDHIs per season, alternate between applications (e.g. benzovindiflupyr at GS 32 (T1) and isoflucpyram or fluxapyroxad at GS 39 (T2).
- Alternate active ingredients if applying SDHIs at GS 39 (T2) and GS 59 (T3) in the same way of for GS 32 (T1) applications.
- Alternate mixing partners, ensuring they always have efficacy against the pathogen too.