Relentless wet weather may force some growers to combine T0 and T1 fungicide applications amid rising septoria pressure and resistance concerns.
For many, the insurance policy that is the T0 fungicide spray is unlikely to be applied given poor soil conditions, which have prevented many fieldwork operations and the fact crop growth stages have exceeded the T0 timing across much of the country.
While the cold weather has slowed the development of rust and mildew, septoria remains a concern for many growers.
Bayer technical manager, Gareth Bubb says: “The main disease concern here in the West is septoria and the wet weather is compounding the problem. Not many T0s have been applied and leaf 3 is now emerging so there will be a lot of people who will combine the T0 with the T1 and some that will omit the T0 altogether and go in with a more robust T1.
“My view is that it is still worthwhile applying the T0, even if you are only 7-10 days prior to your planned T1 date. The problem is that if you get within this and you decided not to go with your T0 and your T1 gets delayed due to bad weather, you are in a desperate situation.”
If the T0 is missed and the T1 is applied early, Yorkshire-based Frontier agronomist, Andrew Roy says a T1.5 could be justified. “With such poor travelling conditions and stressed crops, there has been little opportunity for T0 spraying and as time drifts on, many early crops could be moving towards an early T1 application. If this happens, we will have to watch the gap to T2 and if necessary use a T1.5 to extend cover through this period.”
The decline in curative control from triazoles and SDHIs means it is particularly important that growers aim for effective control early in the season, which means using robust fungicide rates, adds Mr Roy.