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Putting the finishing touches on disease control in wheat
Fungal diseases in wheat have not been a big issue this past season. Still, it doesn't hurt to dot the i's and cross the t's regarding disease control before a new season. Bayer spoke about it with Crop Advisor and grain specialist Simon Jensma.
To start with, a look back at the 2023 season: how did it go in terms of fungal diseases?
"As far as septoria and yellow rust are concerned, it has been a fairly damage-free season. Early in the spring there was some septoria present, but due to the drought in June this did not really continue. We did not see much yellow rust last year either. Until the harvest - which unfortunately largely fell into the water due to persistent rain - we mainly saw reasonably healthy crops."
So mold control will not have been so necessary in 2023...?
"You might think that, but that is certainly not the case! Even with low disease pressure, the use of fungicides has a clearly positive effect on quality and yield. For example, over the past two years we have carried out disease tests in seven different wheat varieties. We know that - even with good yields of well over 10 tons per hectare in untreated fields - quite a few extra kilos can still be achieved on shore with spraying against fungal diseases. With T1 and T2 spraying this was an average of 17% compared to untreated, or more than one and a half tons extra. With T2 spraying alone, this was 9%. So it certainly makes sense to carry out T1 and T2 spraying. And if that is already more than one and a half tons with a low disease pressure ", then this is even more so when there is high disease pressure. The (mainly preventive) effect of fungicide ensures that crops can grow undisturbed under conditions with higher disease pressure. That is and remains a major determining factor for the yield."
What are the biggest challenges currently when it comes to fungal diseases?
"The first thing I would mention is the new yellow rust physios that are emerging in Europe. In the Netherlands, the Warrior and Benchmark physios are mainly known, but elsewhere in Europe other variants are also emerging, such as the Kalmar and Amboise physios. In practice has shown that prothioconazole – one of the active substances of Ascra Xpro – has continued to perform well against these physios so far."
"We must also remain alert to septoria. Although the sensitivity of the monitored European populations to various active substances and groups has remained fairly stable in recent years, there are some nuanced differences. For example, the sensitivity of septoria to fluopyram - a of the three active substances Ascra Xpro – to still be very high. Together with Bixafen – that too Ascra Xpro - there is even a complementary effect. In other words: both substances complement each other, making the whole stronger. That makes that Ascra Xpro is still one of the best agents against fungal diseases in wheat.”
What about the optimal application times for T1 and T2. Are these properly complied with in practice?
"T1 spraying is best carried out between the first and second nodes of the wheat. As a rule, this is also done, unless there are other activities that have equal priority - such as planting potatoes, in which case it is can sometimes be a little later. The starting point for a T2 spray is when the flag leaf is completely present. There too we sometimes see some delay among growers - for example to get a slightly longer effect against rust or some effect against spike fusarium This does not necessarily have to be a bad thing, although if there is a real threat of fusarium, it is better to use a T3 spray (mid flowering) with Prosaro are carried out."
At what time - T1 or T2 - is Ascra Xpro best used?
"Some suppliers recommend it at T1, others at T2. At both times Ascra Xpro its value. At T1 a little more towards septoria and yellow rust, at T2 a little more towards septoria, brown rust, fusarium and also snow mould. The only difference is that for T1 a dosage of 0,85 l/ha applies and for T2 a dosage of 1,1 l/ha applies."
