Spring has descended upon us and we see winter crops begin their flush of spring growth, looking more promising than they have done since planting. Those crops have begun to show their future yield potential, while our spring crops were drilled with a promising late-March/ early-April sowing date. So, it seems that our fields have far more reason to feel normal than us folk, given the strangeness and unfamiliar atmosphere of the world around us.
Having crops that feel normal now is arguably unexpected, given that the first six months of the winter-crop year has been a period of relentless rainfall. This gave us challenging drilling conditions and very variable crop establishment outcomes, which have resulted in a mixed bag of winter cereal crops.
But, we have been in this situation a few times before in the last decade, so it is not a totally unique experience. What is more unusual this year is the huge variation evident across farms and regions of the country.
Fungicide tools
On the fungicide front, the two most significant topics are the use-up period for chlorothalonil products over the next few months and the introduction of the first new triazole fungicide since 2005. So, there is a big positive and a big negative to the fungicide market, which will change a lot of what we have been used to for the last decade.
There are two other very important determinants for our fungicide programmes. One is our weather pattern, as this is linked to disease incidence and the fungal infection pressure over the spring and summer period. The other key factor must be economics, more specifically, grain price and crop value. This currently seems very unpredictable looking five to six months ahead, based on the volatility of markets in recent weeks. So, one could form a view that the outlook is totally uncertain.
There is always potential
However, there is a level of certainly and clarity that we can bring when making decisions on fungicide use and disease control in cereal crops for the year ahead.
One should not underestimate the ability of winter cereal crops to improve and compensate as we move through late spring and into summer. Also, there is a very strong link between grain price and cereal profitability, so every price increment above €140/t to €150/t is very positive for profitability. So it’s clear that profitability is very price sensitive (Figure 1).
Recommended fungicide use
It is also important to take into account that there is a much more insensitive relationship between grain price and spend on key crop protection inputs – this includes herbicides and, most notably, fungicides. This is very well researched and proven by many independent studies, both locally and internationally.
However, this fact seems to be frequently ignored by many otherwise smart and socially savvy farmers and advisers, who prefer simplified “reduced spend” sound-bites to scientifically sound and proven optimum use strategies. So, more robust fungicide programmes are equally sound and sensible in challenging grain price scenarios, as they are in higher grain price markets.
Stay with the basics
Well-timed fungicides are highly effective in providing well-managed disease control on cereal crops, with moderate to large benefits in both grain yield and quality. These benefits often add up to 4-5t/ha on winter wheat (including a number of high-yielding trial sites in Ireland and the UK in 2019) and 2-3t/ha on winter oats and winter barley.
Sometimes, the benefits are more modest at 0.5t/ha to 1.5t/ha, but this is highly unpredictable and needs a lot of dry weather, especially in June and July, which is not normal Irish weather.
For winter wheat crops, a modest spend on early-season disease control, T-zero and T1, could be a pragmatic approach, but it may also be that this should become more robust, as crops improve for T2 and ear sprays. This is a reliable strategy for backward winter wheat crops, but the treatments should still be good and well-timed, using decent fungicide rates and mixtures.
This is very important because the lower leaves – leaf-4 up to heading and leaf-3 to the end of grain-fill – are much more important in wheat crops with an open canopy in 2020 than was the case for a nice, even and dense canopy in 2019. If these crops look decent by the middle of May, then keep pushing them with good nutrition and robust crop protection and they can deliver close to full crop potential.
This statement is made with scientific confidence, as it is well-proven from replicated field trials that low plant stand/open canopy crops can deliver 95% to 98% of the grain yield of a normal-density wheat crop.
Chlorothalonil still can be a key part of the winter wheat fungicide programme this year. Use it as a key contact partner to the systemic fungicides all the way through to T2. A contact fungicide used on its own is limited in its benefits for overall disease control, so keep that in mind and use it with good partner options, especially at T1.
A T1.5 is an unlikely option this year, as later-sown crops have tighter spray intervals and the T1 to T2 interval should be suitably tight given normal-type weather.
New kid on the block
The new triazole fungicide Revysol looks to be a very attractive option for T2 use in wheat. It is an interesting and technically strong product for septoria control and has showed excellent performance in independent trials in Ireland in both 2017 and 2019, with clear benefits compared to current standards (2018 was a non-event due to the summer heat wave and crop burn-up).
As an azole, Revysol has all of the familiar properties of this chemistry class and fits well into the demands of fungicide programmes in Irish conditions. So, the advice is to work out how to use it best, rather than trying to find a reason not to use it. The cost challenges of a new azole can be carefully managed by judicious rate decisions and good partner choices.
The reality is that this new azole fungicide will be at its best and most effective in its first few seasons following introduction than in future years, so this why it should be used now. The more questionable aspect of this new azole is, whether to use it once or twice – T2 only or T1 and T2?
In most situations, I would advise that T2 use on any wheat crop is well-proven. T1 use is a more debatable option and other SDHI/azole products may offer more cost-effective benefits in terms of broad-spectrum disease control – eyespot, mildew and rusts – as well as having a well-proven performance.
Barley and oats
One other factor relating to new product introductions is that they tend to bring keen pricing offers for existing products. One can expect value offers relating from technically good to very good SDHI and azole fungicides this year.
This can be valuable for fungicide choices for barley and oats. While there is a significant focus on the recent resistance shifts related to septoria in wheat and ramularia in barley, the current SDHI and azole chemistry has otherwise delivered an excellent technical story on barley and oats.
Chlorothalonil use, being mindful of the latest cut-off dates, is a key inclusion at T2 on barley crops. Where and when it is not an option, Folpet is the best alternative, with a lower but reliable efficacy expected. Also, Folpet timing needs to be very good and in high-risk situations, a split-dose application may give the best results.
Choices for disease control programmes this year should be influenced by disease pressure, grain price and yield prospects. Good robust fungicide programmes virtually always pay. Yield potential, especially in wheat, could improve considerably as we get into rapid spring growth. Revysol should be a definite inclusion on wheat at the T2 timing.There may be good value in products that are still very useful on barley and oats this year.
Spring has descended upon us and we see winter crops begin their flush of spring growth, looking more promising than they have done since planting. Those crops have begun to show their future yield potential, while our spring crops were drilled with a promising late-March/ early-April sowing date. So, it seems that our fields have far more reason to feel normal than us folk, given the strangeness and unfamiliar atmosphere of the world around us.
Having crops that feel normal now is arguably unexpected, given that the first six months of the winter-crop year has been a period of relentless rainfall. This gave us challenging drilling conditions and very variable crop establishment outcomes, which have resulted in a mixed bag of winter cereal crops.
But, we have been in this situation a few times before in the last decade, so it is not a totally unique experience. What is more unusual this year is the huge variation evident across farms and regions of the country.
Fungicide tools
On the fungicide front, the two most significant topics are the use-up period for chlorothalonil products over the next few months and the introduction of the first new triazole fungicide since 2005. So, there is a big positive and a big negative to the fungicide market, which will change a lot of what we have been used to for the last decade.
There are two other very important determinants for our fungicide programmes. One is our weather pattern, as this is linked to disease incidence and the fungal infection pressure over the spring and summer period. The other key factor must be economics, more specifically, grain price and crop value. This currently seems very unpredictable looking five to six months ahead, based on the volatility of markets in recent weeks. So, one could form a view that the outlook is totally uncertain.
There is always potential
However, there is a level of certainly and clarity that we can bring when making decisions on fungicide use and disease control in cereal crops for the year ahead.
One should not underestimate the ability of winter cereal crops to improve and compensate as we move through late spring and into summer. Also, there is a very strong link between grain price and cereal profitability, so every price increment above €140/t to €150/t is very positive for profitability. So it’s clear that profitability is very price sensitive (Figure 1).
Recommended fungicide use
It is also important to take into account that there is a much more insensitive relationship between grain price and spend on key crop protection inputs – this includes herbicides and, most notably, fungicides. This is very well researched and proven by many independent studies, both locally and internationally.
However, this fact seems to be frequently ignored by many otherwise smart and socially savvy farmers and advisers, who prefer simplified “reduced spend” sound-bites to scientifically sound and proven optimum use strategies. So, more robust fungicide programmes are equally sound and sensible in challenging grain price scenarios, as they are in higher grain price markets.
Stay with the basics
Well-timed fungicides are highly effective in providing well-managed disease control on cereal crops, with moderate to large benefits in both grain yield and quality. These benefits often add up to 4-5t/ha on winter wheat (including a number of high-yielding trial sites in Ireland and the UK in 2019) and 2-3t/ha on winter oats and winter barley.
Sometimes, the benefits are more modest at 0.5t/ha to 1.5t/ha, but this is highly unpredictable and needs a lot of dry weather, especially in June and July, which is not normal Irish weather.
For winter wheat crops, a modest spend on early-season disease control, T-zero and T1, could be a pragmatic approach, but it may also be that this should become more robust, as crops improve for T2 and ear sprays. This is a reliable strategy for backward winter wheat crops, but the treatments should still be good and well-timed, using decent fungicide rates and mixtures.
This is very important because the lower leaves – leaf-4 up to heading and leaf-3 to the end of grain-fill – are much more important in wheat crops with an open canopy in 2020 than was the case for a nice, even and dense canopy in 2019. If these crops look decent by the middle of May, then keep pushing them with good nutrition and robust crop protection and they can deliver close to full crop potential.
This statement is made with scientific confidence, as it is well-proven from replicated field trials that low plant stand/open canopy crops can deliver 95% to 98% of the grain yield of a normal-density wheat crop.
Chlorothalonil still can be a key part of the winter wheat fungicide programme this year. Use it as a key contact partner to the systemic fungicides all the way through to T2. A contact fungicide used on its own is limited in its benefits for overall disease control, so keep that in mind and use it with good partner options, especially at T1.
A T1.5 is an unlikely option this year, as later-sown crops have tighter spray intervals and the T1 to T2 interval should be suitably tight given normal-type weather.
New kid on the block
The new triazole fungicide Revysol looks to be a very attractive option for T2 use in wheat. It is an interesting and technically strong product for septoria control and has showed excellent performance in independent trials in Ireland in both 2017 and 2019, with clear benefits compared to current standards (2018 was a non-event due to the summer heat wave and crop burn-up).
As an azole, Revysol has all of the familiar properties of this chemistry class and fits well into the demands of fungicide programmes in Irish conditions. So, the advice is to work out how to use it best, rather than trying to find a reason not to use it. The cost challenges of a new azole can be carefully managed by judicious rate decisions and good partner choices.
The reality is that this new azole fungicide will be at its best and most effective in its first few seasons following introduction than in future years, so this why it should be used now. The more questionable aspect of this new azole is, whether to use it once or twice – T2 only or T1 and T2?
In most situations, I would advise that T2 use on any wheat crop is well-proven. T1 use is a more debatable option and other SDHI/azole products may offer more cost-effective benefits in terms of broad-spectrum disease control – eyespot, mildew and rusts – as well as having a well-proven performance.
Barley and oats
One other factor relating to new product introductions is that they tend to bring keen pricing offers for existing products. One can expect value offers relating from technically good to very good SDHI and azole fungicides this year.
This can be valuable for fungicide choices for barley and oats. While there is a significant focus on the recent resistance shifts related to septoria in wheat and ramularia in barley, the current SDHI and azole chemistry has otherwise delivered an excellent technical story on barley and oats.
Chlorothalonil use, being mindful of the latest cut-off dates, is a key inclusion at T2 on barley crops. Where and when it is not an option, Folpet is the best alternative, with a lower but reliable efficacy expected. Also, Folpet timing needs to be very good and in high-risk situations, a split-dose application may give the best results.
Choices for disease control programmes this year should be influenced by disease pressure, grain price and yield prospects. Good robust fungicide programmes virtually always pay. Yield potential, especially in wheat, could improve considerably as we get into rapid spring growth. Revysol should be a definite inclusion on wheat at the T2 timing.There may be good value in products that are still very useful on barley and oats this year. 
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