One of the mildest winters on record, coupled with drought-like conditions for much of the spring – up until this past week – has caused real concern for many cereal growers but there is still potential to produce some high yielding, bumper quality crops.
While this week’s rain has been a huge sigh of relief, it will nevertheless increase disease levels in all crops, regardless of how clean they initially appeared. 
Furthermore, while growers may be able to reduce spray dosage rates on some sites, all crops will need some sort of T1 and T2 chemical spray, depending on site conditions, crop variety and disease level, according to those in the know.
Over the past 10 days, disease has been seen in both winter wheat and barley at the two SRUC trial sites at Oldmeldrum, Aberdeenshire, and at Boghall, Edinburgh – despite the differences in weather, soil type, soil conditions and crop variety grown.
In Aberdeenshire, all inputs went in ahead of schedule, in good beds and came through quickly at the Saphock Farm site, Old Meldrum, which since then, had enjoyed an early spring. 
According to Douglas Gray, of Frontier Agriculture, moisture was needed to capitalise on that good spring weather. However, all was looking pretty robust despite some cold east winds which did hold growth back. With this in mind, he advised growers not to let their T2 sprays slip.
Looking at winter barley crops, he said: “Untreated Cassia plots are hoaching with rynchosporium. It has been drier than previous seasons, but there’s been enough moisture to keep it going. 
“It isn’t high in the canopy, but it only needs some rain to get going.
“We’ve lost that glow in crops. But the driver for yield in winter barley is the T1 when heads and grain sites are set. 
“We haven’t lost that potential yet, but we need moisture.
“If it stays dry, then there is the chance to trim back a bit. But I would still look for a good dose of prothioconazole with a morpholine or strob and CTL.”
In winter wheat, Mr Gray said there is the “odd bit” of yellow rust, mainly in Myriad, which popped out between the T1 and T2.
“It’s all about tailoring products to what you have. Where yellow rust is a concern, I’ll probably opt for something like Ceriax (epoxiconazole + fluxapyroxad + pyraclostrobin), if not then it will be Skyway (prothioconazole + bixafen + tebuconazole),” he said adding that it is important to keep spray intervals tight.
“We’ve still got some mildew hanging around from the winter. You’ve got to control it at the T1 and in most cases we’ve done that. But it is still visible in a plot of Leeds here. 
“This is one reason for opting for prothioconazole at T1. I think it is unlikely to spread onto the upper leaves but prothioconazole at T2 would provide further suppression.’
Echoing that, Professor Fiona Burnett, of the SRUC added that there is also potential for fusarium and late ear disease in barley crops when the North-east had experienced a run of late summers in recent years.
“Don’t assume that with this dry spell you’ve got out of jail. The weather is out of our control so it is important to do what you can before harvest,” she said, adding that so much is dependant on the weather between now and booting in winter barley.
The moving situation in the industry with ramularia, also means growers have to ensure a mixture of chemistry at the T2 is more potent. Hence, she advised a three-way mix of azole, SDHI and multi-site. 
“It’s a win, win, situation where it will deal with a complex of diseases such as rhynchosporium, net blotch and mildew.
“If disease pressure is low I would rather see growers manipulate the dose over leaving something out. These three-way mixtures are doing a good job on the crop and stewarding products as well.”
Yellow rust in winter wheat  however, appears to be a different kettle of fish. 
“With susceptible varieties, you know you’re going to have a problem before you start. With the others, you’re not sure what could happen. 
“Yellow rust comes and goes here. This season, it appears to be where it has been a bit sheltered and where soil is drier. I’m also a little bit surprised by the level of Septoria in some of these plots.”
As a result, Professor Burnett advised an SDHI at T2. “We have a strong portfolio of T2 products, but an SDHI is ‘a given’ at T2. There might be the odd exception where an azole + CTL + strob mix would suffice but it really would be the exception.
“In trials, the newer one like AscraXpro ((prothioconazole + bixafen + fluopyram) and Elatus (prothioconazole + benzovindiflupyr) are a fraction ahead in terms of disease control and yield but it will all depend on how they are priced.
“There’s a perception that if your flag leaf spray is delayed then you don’t get the full value of it and then delay an ear spray. But then you’ve moved from one compromise to two. My view is even if things go a bit awry at T2 get back on track at T3.
“With our extended growing season in the north the T3 is important. Not just as an ear protectant, but also against late foliar disease. You do need to protect green leaf area so timing and dose is important.
“Hitting the correct timing is always best. But if you get it wrong better to be a tad early than late. It’s where gaps get extended where disease gets in. Too short is definitely better than too long.”
Bayer’s Grant Reid agreed: “We want to see prothioconazole being used in mixtures. In terms of azole it is the only real option so we need to look after it.
“There’s only so far you can trim rates. Even with SDHI potency they need the support of a respectable dose of an effective azole. 
“SiltraXpro remains our most potent option but I wouldn’t want to see rates move below 0.4 l/ha. We see 80gm/ha of prothioconazole as a minimum. It doesn’t matter what the season, or crop – we have to protect from the word go because there are so few eradicants,” he said.