May 16, 2017
Sam Patchett Blog: Plenty of time for things to change
While hoping for the best, another mild winter leaves Sam Patchett preparing for the worst with his disease management programme.
So far – fingers firmly crossed – the weather has been much kinder to us than last season. But it’s only early April yet, so there’s plenty of time for things to change.
As ever, wet weather got in the way of our late winter and early spring fieldwork. Our cereals – even later-drilled wheats – have come out of the winter well, though, and our early OSR varieties, in particular, have been romping away and into flower.
It’s very much of a waiting game as far as our disease management is concerned. Another mild winter means the usual suspects are not hard to find in either our cereals or rape. So we know there’s plenty of pressure set to explode on us if conditions allow.
That’s why we’ve been putting more emphasis than ever on T0s to carry our wheats through to theT1s that should be going on as you read this. The very last thing we want is disease pressures that either force us to go in too early or don’t give us the flexibility to cope with the sort of weather delays we so often suffer up here.
Having kept things tidy early on, with the exception of any particularly rust-susceptible varieties where a strobilurin at T1 will be important, we’ll be using SDHIs at both T1 and T2 in many cases this season.
In combatting Septoria, we’re so reliant on their protective activity these days that we must avoid putting them under massive resistance-encouraging curative strain at T2. At the same time, my research colleagues saw an advantage of 0.75t/ha from two SDHIs instead of one last season. And this on especially Septoria-resistant, Solace.
Rynchosporium, mildew and net blotch are the key targets for our first winter barley treatment – a combination of triazole, spiroxamine, strobilurin and chlorothanonil – going on as I write. Then at T2 we’ll be stepping-up our battle against the ramularia that is a much bigger issue for us than many appreciate. But this will only be going on from ear-emergence so it doesn’t run out of steam too early.
Although yet to build-up badly, we’re keeping a close eye on light leaf spot in our OSR too. The weather prevented our stem extension sprays – most of which included Toprex for canopy management – being applied until the last two weeks of March. So this and the single robust mid-flowering combination of metconazole and boscalid that is our first choice for sclerotinia control should stand us in good stead here. To which we’ll be adding the most bee-safe pyrethroid to target seed weevil.
A lot of our spring barley and a fair amount of beans are only just being drilled. Decent seedbeds and good growing conditions should help make-up for this delay – aided in the barley with the timely 3-4 leaf dose of manganese and Nutriphite PGA we always find so useful.
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