BASF Funginar #2: Disease risk and considerations for effective management
23.03.2023
Growers need to be prepared for whatever this season will bring and to be aware that already two of their decisions, variety and drilling date, will impact the disease risk they will face.
Disease pressure over the last few years has been low, however, data showing Septoria epidemics over more than 30 years paints a picture of variability, so just because it was low last year does not mean it will be low this year, the next few months will decide that.
Speaking on BASF’s latest Funginar, Dr Rebecca Joynt Senior Plant Pathologist ADAS and Steve Dennis, Head of Business Development, BASF told growers what they need to take into consideration to effectively manage disease risk.
What to consider when building fungicide programmes
Variety
Dr Joynt said, “There is a benefit of all round resistance as a good insurance policy in protecting yield. Both susceptible and resistant varieties show a yield benefit to increasing fungicide inputs. This is far greater in susceptible varieties and so fungicide inputs can be adapted with varietal resistance to maximise the economic margin.”
Drilling Date
Mr Dennis said, “With the average drilling date for winter wheat about 7-10 days earlier than it has been in recent years growers need to be consider how the drilling date affects the resistance rating of their chosen variety. Data from 25 trials over 5 years has shown that where crops are drilled 2 weeks before 7th October, the variety’s effective Septoria resistance rating on the RL list is decreased by 0.6 points.”
Dr Joynt said, “ With this in mind, growers might want to adapt fungicide inputs for varietal resistance. For example if you have a late sown resistant variety you can use reduce inputs and achieve the same yield as you would from a susceptible variety sown early with a higher input programme. It’s all about accounting for those differences and how it affects the margin on farm.
Weather: past and future
It always comes back to the weather, weather we have had and weather still to come.
Coming into spring the baseline level of Septoria is quite high in many crops because of the open weather and high accumulated temperatures over the autumn period. At ADAS Rosemaund in Herefordshire accumulated temperatures are 90 degree days warmer than the long term average, comparable to 7-10 days. This means crops can be considered the equivalent of being drilled 7-10 days earlier than they actually were, again reducing the variety’s Septoria resistance rating.
Generally the risk of Yellow rust is lower this season. It is crops with a later sowing date which are more susceptible to yellow rust and very cold weather in December has worked to control Yellow rust.”
Mr Dennis said, “Looking ahead, weather conditions in the approach to the key T2 timing will drive the level of disease in the crop .Growers should not assume that if disease pressure feels low when T2 is applied that it will remain low and when deciding on their product, timing and rate, need to bear this in mind.
Variable flag leaf emergence
It is not just variable weather growers have to contend with but also variable flag leaf emergence. NIAB TAG research in 2021 showed how uniformly the flag leaves emerged for the same crop of wheat, with a gap of 10- 14 days between the first and last flag leaf emerging for any given variety. This substantial variation in date of full flag leaf emergence within each variety makes pinpointing the right day to spray exceptionally difficult. Waiting for all the flag leaves to emerge means there is a likelihood that some of your flag leaves are already infected, resulting in a curative situation. If, to avoid being curative growers decide to go early then not all of the flag leaves will have emerged.
Flexible Chemistry
Growers need flexibility from their chemistry to deal with this and is proven to be the most curative product in the market. Revystar® XE’s flexibility enables growers to wait for full emergence of the flag leaf without having to go too early and compromise full leaf coverage with fungicide. Revystar® XE can also be used earlier, if growers choose not to wait for full flag leaf emergence because it gives very good curative activity on leaf 2, proven to reduce the movement of disease up onto the flag leaf.
Irrespective of the variety there are still significant increases in yield to be had by keeping the dose rate of Revystar® XE up, increasing dose mitigates increased disease risk. The recommended dose rate of Revystar® XE at the T2 timing is 1l/ha and it will cope with whatever this season throws at us.”
To watch a recording of the full funginar, please north_east click here
Use plant protection products safely. Always read the label and product information before use. For further product information including warning phrases and symbols refer to www.agricentre.basf.co.uk. Revystar® XE contains mefentrifluconazole (Revysol®) and fluxapyroxad (Xemium®). Revystar® XE, Revysol® and Xemium®, are registered Trademarks of BASF. All other products are those of other manufacturers where proprietary rights may exist. © BASF 2023. All rights reserved.
