Unsettled weather for much of April means septoria, not rusts, will be the most important disease to control as T1 fungicide sprays go on to many wheat crops this week, according to FWi’s team of agronomists.
Neil Donkin said the disease was the main one present in crops in the Gloucestershire region and robust rates of triazole fungicide would be needed to ensure good control.
“Most winter wheat crops will have their T1 fungicide and growth regulator treatments in the last week of April or the first few days of May, targeting final leaf three when it is half-emerged.
“It is worth dissecting the plant to check which leaf is emerging, as many crops which appear backward have, in fact, reached the correct stage for treatment,” he said.
Suffolk-based Will Foss also said septoria was the main target, but yellow rust had also been found in some crops of Robigus. “There is also quite a lot of stem base browning – mainly fusarium and occasionally eyespot. In most cases crops have received a triazole + strobilurin combination at T1 targeted at these diseases and to improve nitrogen utilization.”
While brown rust incidence was lower than last year, he warned that risk of the disease was always present on susceptible varieties and growers should select fungicides accordingly.
In East Lothian, forward wheat had just reached the T1 timing and Andrew Riddell advised growers to assess disease risk carefully, focussing on septoria, eyespot, mildew and yellow rust. “Yellow rust can be found, but less widespread compared to this time last spring,” he noted.
Oilseed rape was at early flower and would soon receive a fungicide, he added. “Sclerotinia-protecting fungicides will be more cost effective this year, so keep the rates up.”
Wheat in Hampshire was receiving its T1 spray, but it was oilseed rape that was still causing concern for James Boswell. “This crop has been the bane of growers lives this spring. Pigeons continue to be causing damage and many crops have no main flowering head on the plant – how this will affect yield is unknown, but with a cold, wet April the crop has not yet compensated.”