Emerging from the cold and wet at altitude

20.04.2018

Septoria tritici is our main issue here in the west, we are reasonably wet (880mm average) and quite high up (600 ft above sea level) and so it is quite damp. We can get bad rust but that seems to be down to varietal issues rather than anything else.”

This is Toby Hogsbjerg’s assessment of the disease risk profile for the 390 ha of winter wheat he has on his farm in the Cotswolds. Mr Hogsbjerg said, “throughout the early spring we’ve had no major disease issues, we will always have a bit of septoria at the base but I think it was held back by the cold weather.”

This year RGT Illustrious is the variety in the farm’s Real Results trial field; a first wheat after oilseed rape.  Mr Hogsbjerg said, “It has gone in very well in the middle of October. We run variable rate seeding, trying to get a better balanced crop which we seem to have achieved so far.

Obviously the T1 spray  is weather and disease dependent. If the crop in question is reasonably clean then I will probably go down a cost effective SDHI azole route, potentially a Keystone (epoxiconazole and isopyrazam) Bravo (chlorothalonil) mix.

If we have disease issues or if we get delayed due to weather, then I will probably go with a Librax (fluxapyroxad and metconazole) or Adexar (epoxiconazole and fluxapyroxad) type product with Bravo as well.

If we do see rust early then the Elatus Era (benzovindiflupyr and prothioconazole) will probably be used but hopefully we will not be seeing rust rearing its head in the RGT Illustrious.”

He added, “In the past I have used an SDHI at T1 and T2. Last year I tried a few combinations without SDHI at T1. We got far better results in terms of yield, greening and rooting, with an SDHI at T1, but using sensible rates, I wouldn’t cut back rates as obviously resistance is an issue.”

The split of the fungicide spend is normally the same at T1 and T2.

Mr Hogsbjerg said, “As a rule of thumb, if I see a lot of disease at T1 then we will spend more then to keep the plant as clean and healthy as possible. If we get a hot dry spell through April / May or May /June, I need the plant to be as green and disease free as possible going into the dry spell, so it has enough energy to keep itself going through to fruition so I tend to go with a T0 and a reasonable T1.”

Mr Hogsbjerg has two farms, eight miles apart which can have different weather patterns and establishment dates on each. His fungicide programme is prescribed according to the variety, drilling date and condition of the crop. He said, “If I can save money because it is clean then we will do, I don’t tend to blanket treat things.

We are of course conscious of resistance management and so use CTL in the mix and normally try to use an SDHI azole mix, never going anywhere below probably half rate. We would try to stick above this if financially we can make it work. I tend not to cut rates due to the budget. If disease is prevalent and active then we need to put a good ¾ dose on at least to do the job properly.”

Random tissue testing is done for micronutrients. Mr Hogsbjerg said, “I would sooner spend money on nutrition, in that sense than I would on fungicide, if we can go down that route.

I always think a healthy plant is far better at resisting disease than one that is under stress and we have seen results to this effect. We we now use straight trace elements rather than mixtures and we are definitely seeing better longevity on the shallow soils going into the summer. We try and get these micronutrients on, where needed with the early sprays.”

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