EARLY reports of rust and trouble curing septoria tritici if it’s allowed to establish, mean winter wheat growers must stay on the front foot against diseases in 2017, according to Syngenta's field technical manager, Iain Hamilton.
As the main UK wheat disease, septoria is pretty much always present, said Mr Hamilton, but curing established infection has become much more difficult following its reduced sensitivity to key fungicides, notably azoles.
There has also been early reports of yellow rust affecting wheat varieties in Lincolnshire and Oxfordshire this season, he pointed out. “No parts of the country are immune to rust or septoria,” said Mr Hamilton. “Although yellow rust cases have started off fairly isolated, it’s important to remember that these early sightings come on the back of a high pressure year.
“The 2016 season demonstrated all too clearly just how difficult yellow rust is to control if it’s not prevented early enough. So it’s vitally important that growers learn the lessons from 2016.
“I’m not suggesting crops need treating now. The winter weather will play a big part in how disease develops, but it will be important not to let any disease escalate. We saw in 2016 just how important a T0 fungicide can be for achieving this – even if crops look clean at the T0 timing, which is typically in March.”
Although it is the upper leaves of winter wheat that contribute most to yield, the aim is to block disease getting up onto these in the first place, he explained. “You need to take into account both rust and septoria at T0 – using something like Bravo (chlorothalonil) against septoria and recognised triazoles against rust, or a combined chlorothalonil + triazole treatment, such as Cherokee.
“Once disease takes hold you can’t turn the clock back. But growers can waste a lot of money trying,” Mr Hamilton added.