Variety choice can make all the difference to final yield
It’s not just the choice of fungicide which matters, it’s the way that you apply it, together with the potential of the variety that you’re growing, that can make all the difference when going for yield and maximising returns this year, according to three experts.
“The top four wheats have a 3-4% yield advantage over the next best,” says John Miles of KWS. “When you then start to investigate their crop protection requirements and the best use of spray opportunities, there’s every chance to go for yield.”
Better septoria control levels can be achieved now that the SDHI fungicides are approved and available, says Steve Dennis of BASF. “We’ve had strong rust products for a while, but septoria and eyespot have been the two disease targets for improvement. Now that we’ve achieved that aim, the focus is on using them correctly.”
And while that means exploiting their strengths at T2, it doesn’t let growers off the hook at T1, he advises. “Better T2 fungicides aren’t a reason to weaken your T1 choices. In fact, there’s plenty of trials evidence to support the importance of getting your T1 right as the quality of T2 products increases.
“It allows you to unlock more potential.”
That’s a view that is shared by KWS agronomy consultant Bob Simons and Agrovista’s technical manager Mark Hemmant, who point out that fungicide programmes are planned on risk and should be tailored to local disease pressure and variety.
They both stress that growers shouldn’t be tempted to change early season agronomy decisions – it’s the later ones which offer the potential to trim costs without adversely affecting yield.
“The weather has the greatest influence, regardless of what state crops come out of the winter in,” says Mr Simons.
He calculates that ÂŁ90/ha will cover the cost of most fungicide programmes on high yielding sites, allowing for the introduction of SDHI chemistry. “That could go up to as much as ÂŁ120/ha in the highest risk situations, or down to ÂŁ50-60/ha for a simple programme on lower yielding sites.”
The T0 treatment is now routine, he reports. “It’s true that yield responses from T0s are less consistent than those of later spray timings, but their role is to manage disease progression and reduce the pressure on subsequent applications.”
He believes they should be triazole-based this year, to target rusts. “Growers will spend ÂŁ5-15/ha, depending on the risk.”
At T1, the main threat is foliar disease, but eyespot shouldn’t be overlooked, he warns. “Two dry springs have seen low levels of eyespot, but varietal resistance to the disease isn’t great and earlier sown crops will be at risk.
Both boscalid and prothioconazole have good eyespot activity, notes Mr Simons. “But the need for rust control this year will influence product choice and will probably favour the use of Tracker (boscalid + epoxiconazole).”
Where this is followed with Adexar at T2, there’s been a 0.7t/ha yield benefit in trials, he reveals. “It’s come from good stem base disease control plus better septoria control. Of course, dry soils this spring will also push people towards Tracket at T1 – it’s given a consistent yield response in dry years.”
At T2, the new SDHIs bring some practical flexibility, he continues. “This has a benefit where spray intervals are disrupted and timings get stretched. We are fortunate that the most effective curative choices don’t lack persistence.”
Mr Simon’s final point is that the larger farms are likely to have several days of susceptible varieties to spray, often with a limited number of spray days. “This is where the combination of robust fungicide products and best application techniques comes in.”
Application trials carried out by Agrovista confirm this, notes Mark Hemmant, who says that there are real effects from how products are applied.
“We’ve found that using a water volume of 100 litres/ha is better than 200 litres/ha, especially in high disease pressure situations.”
Angling nozzles is also beneficial, he continues. “Alternating them forward 30Ëš and down has given the best results, with both flat fan and air inclusion nozzles.”
And while flat fan nozzle are better than air inclusion types, the practicalities of getting the job done mean that the latter are often favoured. “This is where adjuvants have a role. Work is continuing on these.”
