Considerations for e ective disease management for the season ahead

Weather patterns over recent years have resulted in relatively low disease pressure; however, this does not mean there will be low disease pressure again this year. Growers need to ensure they know the risk associated with the variety they are growing and its drilling date and then use this knowledge to consider how to adapt fungicide inputs.

Considerations when planning fungicide programmes

Variety: Knowing the varietal resistance, from the AHDB Recommended List (RL), is the starting point to managing disease risk and there is a bene t of good all-round resistance as an insurance policy in protecting yield.

Dr Joynt said: “Twenty years of data from AHDB RL trials where untreated and treated trials were co-located allows us to see the bene t of fungicide programmes on those crops, giving an average increase of 2.13t/ha.

Susceptible and resistant varieties show a yield bene t to increasing fungicide inputs although this is far greater in susceptible varieties, so in order to maximise the economic margin, fungicide inputs can be adapted with varietal resistance.”

The e ective septoria resistance rating is in uenced by other factors which need to be considered when planning the appropriate fungicide strategy.

Drilling date: A dry mild autumn in 2022 gave favourable drilling conditions and the average drilling date for winter wheat across the UK is approximately 7–10 days earlier than in recent years.

Mr Dennis said: “Growers need to be aware that a change in drilling date will a ect their variety’s septoria risk. Data from 25 trials over ve years shows that where crops are drilled two weeks earlier than 7th October, the e ective septoria resistance rating on the RL list is decreased by 0.6 points. Growers will need to consider whether, in order to control septoria, a more robust fungicide strategy is required.”

Dr Joynt added: “If you have a susceptible variety sown early, it will require a higher input programme to achieve the same yield as a late sown resistant variety.”

Mild autumn temperatures

The accumulated temperature data from ADAS Rosemaund in Herefordshire shows towards the end of February, it was 90 degree days warmer than the long term average, equivalent to 7–10 days.

Dr Joynt said: “This a ects the e ective septoria resistance rating of the variety; crops can be considered being drilled 7–10 days earlier than they actually were.

“Moving into the spring, the baseline level of septoria is high in many crops because of these high accumulated temperatures over the autumn.”

Cold December

The weather patterns of autumn and winter have had an e ect on the relative balance, in terms of risk, of yellow rust and septoria.

The risk of yellow rust is generally a little lower this season. Dr Joynt explained: “Later sowings are more susceptible to yellow rust and in combination with a very cold December, this has worked to control this disease.”

Weather prior to T2

Weather conditions in the approach to the key T2 timing drive the level of disease in the crop when that fungicide application is made. Conditions after T2 determine how the disease subsequently develops.

Mr Dennis said: “It can’t be assumed that just because pressure feels low when T2 is applied that it will remain low. In 2021, growers found themselves in a protectant situation when the T2 was applied but conditions following application actually led to rapid disease development.”

Impact of crop physiology on septoria risk

NIAB TAG work in 2021 showed how variety in uenced how uniformly the ag leaves emerged.

Mr Dennis said: “2021 was a cool spring with crops growing slowly but actually the principle remains the same for any year. Researchers made regular visits to a variety trial, all drilled on the same day and evaluated what proportion of ag leaves had emerged. They found a gap of potentially 10–14 days between the rst ag leaf and the last ag leaf emerging for any given variety.”

Leaf layer emergence dictates the time exposed to septoria infection and with considerable variation in date of ag leaf emergence within a variety, targeting the precise day to spray is exceptionally challenging.

Mr Dennis said: “There is a very good chance that some of your ag leaves are already infected if you wait to ensure all of your ag leaves have emerged, putting yourself in a curative situation. If you go early to avoid curativity, then this can be problematic because not all of the ag leaves have emerged.

“Chemistry with the exibility to counter these issues is key. Revystar XE delivers exibility.”

Mr Dennis explained: “Because Revystar XE is proven to be the most curative product in the market it gives more exibility, so growers are able to wait for full emergence of the ag leaf without having to go too early and compromise full leaf coverage with fungicide.

“If Revystar XE is used earlier, it gives very good curative activity on leaf 2 reducing the movement of disease onto the ag leaf.

“Even with the strongest genetics, there are still signi cant increases in yield by keeping the dose rate of Revystar XE up. One litre/ha Revystar XE is the recommended dose rate at the T2 timing, and at this rate Revystar XE will cope with whatever the season brings.” FG

Crop management:

What does it take to break wheat yield records?

In 2022, Lincolnshire farmer Tim Lamyman smashed two yield records. His crop of Champion winter wheat yielded a phenomenal 17.96t/ha, and his Tardis winter barley, a staggering 16.2t/ha – both are more than double AHDB’s averages for the year. But how did he do it?

There’s no short answer to this. Mr Lamyman has a very experienced and knowledgeable team, a highly analytical yet open mindset and pays microscopic attention to the details – starting with variety choice.

Variety data

“I need all the data on each variety if I am going to grow it. If I haven’t got that, then it’s just a guessing game,” he says.

Mr Lamyman rst realised Champion’s potential back in 2021. Having previously recognised the variety’s yield and disease scores, he grew a small area and observed other potentially record-breaking characteristics. “The seed heads are phenomenal – up to 15cm long with over 90 seeds of bold grain, and a fantastic ability to compensate for thinner areas,” he says. “It’s high tillering and it’s large, erect leaves allow light to penetrate deeper into the canopy.”

Capturing sunlight is a key element of Mr Lamyman‘s winning strategy and is in-line with an underlying principle of tackling growth-limiting factors. “It’s usually the main limiting factor in the UK,” he says. “In 2022, we were able to capture more sunlight than ever before, and that is the main reason we broke records. We managed to keep plants greener for longer with two elements – fungicides and nutrition.”

E ective nutrient and crop protection programmes

Developing the most e ective fertiliser and crop protection programmes is very much a team e ort with Bionature’s Mark Carter and BASF’s Andrew Smooker contributing to the decision-making. Andrew’s knowledge and expertise is applied to the fungicides and disease control elements of those crop protection programmes.

Sown on 24th September 2021, the winter wheat crop rst received a couple of herbicide applications designed to target black-grass. The spring season kicked o with a fertiliser application on 3rd March. In total the crop received around 300kg/ha of Nitram, with further applications being made on 15th April and 12th May.

On 5th March, a combination of Moddus (trinexapac-ethyl) at 0.05-litres/ha; NKHDelta at 2.5-litres/ha and YaraVita Boratrac 150 at 0.5-litres/ ha was applied.

With water and nutrient access sitting alongside sunlight on the list of potential limiting factors, ensuring strong and healthy root growth is essential. It is why NKHDelta – an amine form of nitrogen from Bionature UK that improves rooting, enabling plants to better access soil reserves – is included within the programme. The Yara BoraTrac serves to address a boron de ciency, while Moddus (trinexapac-ethyl), a plant growth

Pictured (l-r): Tim Lamyman and Robert Lamyman, with BASF’s Andrew Smooker and Phillippa Overson. regulator applied little and often throughout the season, moderates growth without bringing the crop to a standstill.

Regular leaf tissue testing keeps the team informed of how well treatments are working and whether future applications need tweaking.

The next application, made 10 days later, comprised 200kg/ha of Kieserite, which supplied 100kg/ha of sulphur trioxide and 50kg/ha of magnesium.

Fungicide programme begins

On 28th March, the fungicide programme began. Mr Lamyman‘s T0 combined the fungicide, Toledo (tebuconazole) at 0.15-litres/ha, with the growth regulators Moddus (trinexapac-ethyl) at 0.05-litred/ha and 3C Chlormequat 750 at 0.5-litres/ha. Completing the treatment was a mix of macro and micro-nutrients in the form of NKHDelta at 2.5t/ha and TipTop at 2-litres/ha.

At T1, on 25th April, the crop of Champion received: a combination of fungicides, namely Revystar XE at 1.2-litres/ha and Toledo (tebuconazole); growth regulators Moddus (trinexapac-ethyl) at 0.05-litres/ha and 3C Chlormequat 750 at 0.5-litres/ha; and, crop nutrition products NKHDelta at 2.5-litres/ha, XStress at 1-litres/ha and YaraVita Mag o 300 at 0.5-litres/ha.

When choosing fungicides, there’s a wholecanopy approach. Controlling septoria on lower leaves, prevents inoculum build-up through the canopy as the season progresses. It’s a strategy that accumulates yield potential by producing and protecting high crop biomass.

Mr Smooker’s challenge was to develop a crop protection programme that worked alongside Mr Lamyman’s other input approaches: “As well as providing outstanding disease control, we wanted to maximise healthy canopy duration and biomass. The Revysol combinations were pivotal in achieving this.”

Greening e ect

T2 was also about disease control and nutrition. The fungicides were Myresa at 1.2-litres/ha and Syrex at 1.2-litres/ha, which contain revysol, xemium and F500.

“These newer, modern revysol-based fungicides are known for their greening e ects as well as their impact on nitrogen use e ciency,” notes Mr Lamyman. “But really it is the combination of the fungicides and the nutrition that has enabled us to capture more sunlight. One of the major e ects of F500 and the nutritional products is the prevention of leaves rolling, as they slow down ethylene production on days that exceed 25ºC.”

T3 saw the nutrition programme come to aconclusion with XStress at 1-litre/ha, TipTop at 2-litres/ha, CalFlux at 0.25-litres/ha and a late season magnesium boost, through YaraVita Mag o 300, at 0.25-litres/ha. These nutritional products sat alongside the fungicides Proline 275 (prothioconazole) at 0.55-litres/ha and Azo n Plus (azoxystrobin) at 0.25-litres/ha.

The last of the crop protection product, Toledo (tebuconazole) went on at T4 at a rate of 0.3-litres/ha. FG