Key Points
- Two spray ‘straddle’ programmes employing strobilurin/Opus mixtures at GS33 (full leaf 2) & 55 (ear half emerged) have given consistently good margins for the 4th consecutive season on ‘more disease susceptible’ autumn sown wheats. 0.25L/ha Opus at GS30/31should precede the above programme if early stripe rust particularly is observed at that timing.
- The new strobilurin Comet performs similarly to other strobilurins (when mixed with Opus) in lowmoderate disease situations. More work will further examine its robustness in higher disease situations.
- To minimise the risk of strobilurin resistance occurring, it is advised to limit strobilurin use to no more than two applications per season. FAR trials show that following this advice has given reasonable disease control, while maintaining (or improving) profitability.
- In the low disease 03/04 season, the higher rates used in these trials were not necessary.