Growers are being urged to check crops for mildew
20th April 2017
Former AICC chairman Patrick Stephenson is seeing plenty of mildew, in both winter barley and wheat.
Former AICC chairman Patrick Stephenson is seeing plenty of the disease, in both winter barley and wheat. “It’s a double whammy here in Yorkshire. We’ve had more humid conditions that suit the disease, and aided crop development. These more developed canopies are adding to the humidity!”
The problem hasn’t been helped with nitrogen applications being delayed, plant stress helping flush out more of the disease. Susceptible barley varieties such as Cassia have been hardest hit, but the disease is not just limited to these.
The question for Mr Stephenson is T1 decisions. Mildew could still threaten but he will be targeting rhynchosporium and ramularia too. Most crops will be earmarked for an azole + SDHI mix such as SiltraXpro (prothioconazole + bixafen). “The aim is to protect tillers and boost grain sites and the T1 is the right time to do that. You don’t want to delay the movement of azole and SDHI into the leaf so I prefer to leave CTL out and go for robust rates of azole + SDHI,” he notes.
Agronomist Steve Cook of Hampshire Arable Systems says the disease is building in the base of crops. “The weather through March has been particularly mild favouring mildew development. It is the forward, thicker wheat and barley crops which are most at risk – it would appear that it the crop architecture that is determining where mildew is being found.”
It is readily being found in wheat too and he warns that it isn’t just confined to the most susceptible varieties. Mr Cook has seen the disease in both Crusoe and Skyfall. He questions whether any winter wheat variety is really that resistant anymore.
He notes the disease isn’t at yield threatening levels but its presence needs be addressed. “Winter wheat T0 sprays included Corbel (fenpropimorph) for some knockdown or protectants such as Talius (proquinazid) or Fielder SE (proquinazid + chlorothalonil) with a growth regulator.”
Mr Cook is likely to take a prothioconazole approach with T1 sprays. With a significant milling wheat area some early fusarium suppression is welcome, and if mildew threatens then additional activity will bolster protection. “Septoria is your target but not the only concern at GS32. Mildew, eyespot and fusarium may not pose the same yield robbing threat but still need to be controlled to optimise crop performance,” he concludes.