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Flexible fungicide approach with RGT Saki

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It’s been a tricky spring for working out fungicide strategies, after a dry start when septoria was conspicuous by its absence, followed by recent rains and warmer temperatures that favour its development.

We caught up with four of our Grower Club members to see whether growing a highly resistant variety like RGT Saki is making life easier…

Andrew Pitts The Grange, Mears Ashby, Northamptonshire

  • Area farmed 830ha
  • Soils – mostly Hanslope series chalky boulder clay
  • RGT Saki 20ha
  • Drilled mid October
  • First wheat after beans
  • Fungicide applications – T2 only

Omitting both the T0 and T1 fungicide sprays and applying a pared back T2 may seem too much of a risk for many wheat growers, but for Andrew Pitts it makes perfect sense this season for his crop of RGT Saki

Thanks to a dry March and even drier April there has been no disease to be seen on the crop. Although May has seen plenty of rain and the crop is full of promise, Andrew is putting his faith in RGT Saki’s robust resistance scores when it comes to the flag leaf application.

“Leaf 3 remains clean and I’m told there is very little disease out there,” says Andrew. “I am planning to apply 1 litre/ha of Ascra [Bixafen + thiopyram + prothioconazole].

“I can’t see the point of growing a variety with good disease resistance without making full use of that genetic capability. Had we not had rain I would have gone with something cheaper and older like Aviator.”

RGT Gravity and Skyfall had tebuconazole and pyraclostrobin at T0, followed by Adexar (epoxiconazole + fluxapyroxad) at T1, both aimed mainly at yellow rust. The T2 plan is fluxapyroxad and mefentrifluconazole (as in Revystar) at 1 litre/ha.

All crops are grown for seed and will get prothioconazole at T3 to protect against fusarium, the dose dependent on weather at flowering.

“Varieties that can look after themselves and that also yield well are becoming key – triazoles are becoming less effective, septoria will always be out there, and yellow rust is continually evolving,” says Andrew.

“RGT Saki has been an incredibly cheap variety to grow. I expect to grow a lot more next year.”

Richard Langton Wenham Grange, Little Wenham, near Colchester

  • Area farmed 500ha
  • Soils – loamy clay (Beccles series)
  • RGT Saki 42ha
  • Drilled 16 October
  • Second wheat
  • Fungicide applications T0, T1, T2

Wenham Grange received 70mm of rain in the first half of May, providing a very welcome drink for the wheat but producing ideal conditions for septoria development.

“We’re looking at applying a robust T2 to all our varieties to make the most of their potential,” says Richard.

The farm’s RGT Saki is all second wheat and on blackgrass-prone land, so it was drilled in mid-October. “It didn’t go into the best seed-beds but it established well and now looks good,” says Richard.

“Being later drilled it won’t be under so much septoria pressure, and it has a very good disease resistance score as well, so it’ll be last in the queue for the flag-leaf spray.”

Final fungicide choice and rates were still to be decided at the end of last week, but they will reflect the increased disease risk and continue Richard’s risk-averse approach on all varieties this season.

“We went on early with tebuconazole as there was rust creeping about. At T1 we applied Revystar at 0.7 litres/ha as we knew rain was on the way – it looked very good value for money compared with mixing and matching older products.

“I will probably treat all my varieties much same at T2, and I may try some Univoq [fenpicoxamid + prothioconazole] as well, though not on the Saki.”

RGT Saki’s vigour and cleanliness has impressed Richard. “Its resistance is better than most, it’s a good second wheat and its vigorous – it’s the sort of variety we need.”

Sam Morris

Sam Morris

Sam Morris Top Farm, Croydon, Cambridgeshire

  • Area farmed 260ha + 500ha on contract basis
  • Soils – mainly heavy clay
  • RGT Saki 80ha
  • Drilled mid October
  • First wheat after pulses
  • Fungicide applications T0, T1, T2

Sam Morris made use of RGT Saki’s vigour to sow it relatively late into blackgrass-prone land. Despite a slow start in sub-standard conditions, the variety now looks as good as anything on the farm.

“We were toying with the idea of cutting back at T2, but given the recent rain and the value of wheat I think we’ll use a fairly robust fungicide treatment on everything,” says Sam.

The loss of chlorothalonil has added to the uncertainty. “We still don’t really know how that loss will play out. We got away with cheap and cheerful T0 but were probably more robust at T1 than we needed to be, using an SDHI plus triazole at a good rate.

“It’s been a bit of a nervous year. Everything is clean, but we are now in the midst of ideal septoria conditions. Had it stayed dry I’d have tweaked rates more, but we’ve got this far, crops look good, so it’s worth spending the money.”

A good dose of one of the latest SDHI/azole mixes is on the cards, depending on yield potential, for all the wheats, but Sam will be making the most of RGT Saki’s robust disease resistance when it comes to spraying order.

With a large contracted area to spray, his T2 applications take about six days. “All the wheat reaches T2 pretty much at the same time, so if you can buy an extra few days without yield penalty that’s a real help.

“I have just under 2000 acres to get round, so having a genetic advantage at home is well worthwhile.”

Andrew Cawood

Andrew Cawood

Andrew Cawood Burley House Farm, South Milford, North Yorkshire

  • Area farmed 240ha
  • Soils – sandy silt loam to silty clay loam, all over magnesium limestone
  • RGT Saki 23ha
  • Drilled 19 September
  • First wheat after OSR
  • Fungicide applications T0, T1, T2

Wheats at Burley House Farm look very promising after the recent rain and Andrew Cawood is prepared to spend to protect crops that look like exceeding his 10t/ha target.

RGT Saki is currently leading the pack. It is being grown on the farm’s best land and went into good conditions in mid September, drilled at 292 seeds/sq m to achieve the target germinating seed rate of 250 seeds/sq m. “We’re checking all our crops about now to see if how our seed rate decisions have worked, and this look about right,” says Andrew.

Although there has been little disease so far this season, Andrew is not keen to cut back hard on fungicides, although folpet (as in Phoenix) alone at T0 was deemed sufficient.

“We did see some mildew towards T1, so we used Boogie Xpro [bixafen _ prothioconazole + spiroxamine], together with folpet. All crops are clean in the bottom, so we’ll be looking at more of a protective spray for T2.”

Straight mefentrifluconazole [as in Lenvyor Duo] plus fluxapyroxad [as in Imperis XE] plus folpet has been pencilled in, although epoxiconazole and metconazole (as in Brutus) may come into play depending on disease presence and weather.

“A variety like RGT Saki does take the pressure off,” says Andrew. “Although I’m not necessarily using it to cut my fungicide budget, it does provide a wider application window which is very useful. It’s always a question of which wheats do I need to spray first, and a growing a variety like Saki makes that decision much easier.”

RGT Saki summary

  • Very high treated and untreated yields
  • Outstanding disease resistance – Septoria tritici 6.5, yellow rust 8, brown rust 7
  • Resistant to orange wheat blossom midge
  • Good grain quality
  • Short with good straw strength
  • Flexible – drilling date, rotational position, light/heavy soils