Three top actions to help farmers and agronomists manage fungicide resistance in UK cereal pathogen populations have been issued as part of the Fungicide Futures initiative.
Though resistance science is often complex, it is possible to identify simple actions that will slow resistance development, without compromising disease control.
The following three actions should be considered as a checklist to follow prior to applying fungicides at T1 and T2:
- Include an SDHI at T1 in wheat only if the disease pressure warrants it. Where disease pressure is lower or on varieties more resistant to septoria, especially if sown late, an azole plus multisite may be sufficient.
Septoria isolates that are moderately resistant to SDHIs are now present over much of the UK. Using an SDHI at T1 will select further for these, potentially making the population harder to control in the future.
- Include a multi-site at T2 in wheat to protect azoles and SDHIs from resistance. However, be aware chlorothalonil can antagonise partner product curative activity when timings are delayed.
The addition of a multi-site will add to septoria control.
- Include chlorothalonil at T2 in barley. This is particularly important at sites with a history of ramularia, as this disease is likely to be resistant to azoles and SDHIs, as well as strobilurins
In addition to strobilurins, resistance to azoles and SHDIs in ramularia is also widespread in the UK. Chlorothalonil is now the only fungicide that offers good control of ramularia.
Paul Gosling, who manages disease work at AHDB, said: “We need to work together to manage the fungicide resistance problem. Fungicide Futures aims to provide practical anti-resistance messages that farmers and agronomists can adopt to ensure effective disease control this season and for seasons to come.”
Resistance management information can be accessed via cereals.ahdb.org.uk/fungicidefutures