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Highest efficiency spray schedule
"Apply resources on time, always use the full dosage, and rotate the available triazoles as much as possible." According to Bayer beet specialist Sjors Leermakers, these remain the most important guidelines for 2026 to combat leaf diseases in beets.
The fungicide Propel plays a central role in this. "Spray schedules with Propulse provide the best control of Cercospora and therefore also yield the most sugar per hectare," says Leermakers. "Compared to the best reference product, the return is on average €230 per hectare higher. That's pure profit for the grower."
First of all: what options do growers have to tackle foliar diseases preventively?
Incorporating crop residues on time, maintaining a crop rotation of at least 1 to 4, and not placing beet piles on future beet fields are proven measures to keep disease pressure under control. Furthermore, it's important to consider foliar diseases when selecting varieties. In areas where disease pressure is traditionally high, it's highly recommended to choose a variety with a high leaf health score. For me, that's at least an 8, but preferably a 9. These are the so-called CR+ varieties. In practice, we see that these CR+ varieties yield about one percent more sugar in areas with high disease pressure. So, it's definitely worth growing such a variety there.
How do you determine the optimal time to spray against foliar diseases?
The Beet Advisory System (BAS) is the most important tool for determining the optimal spraying time. The BAS gauges measure the climate in the crop and calculate infection points. In recent years, these calculations have proven to be very reliable and provide a good indication of when the first spray should be applied. The first spray is particularly important and largely determines whether the disease remains manageable.
Then the choice of means; what is the best strategy for this?
"The most important message regarding the choice of resources remains: alternate resources. Propel A very important factor in the overall process. Propulse is not only the most potent agent against foliar diseases, but also significantly increases sugar yields. In multi-year trials, programs using Propulse show an average yield increase of €230 per hectare compared to the best reference agent (see also graph). Test data from the IRS confirm this additional yield.
We're confident that spraying schedules with Propulse significantly increase yields. Last year, the difference was around 2 tons of sugar per hectare, according to representatives from the sugar industry. And that despite the fact that disease pressure wasn't even that high. This clearly demonstrates that Propulse is an indispensable link in beet cultivation.
What about the resistance sensitivity of agents against foliar diseases?
"We also have a significant advantage with Propulse in this regard. Propulse contains two active ingredients: prothioconazole and fluopyram. The first—prothioconazole—is a triazole that, until last year, had never been used in beet cultivation. Therefore, potential resistance development wasn't a factor with this substance. Fluopyram takes this a step further. Besides giving Propulse extended efficacy, it also attacks leaf diseases like Cercospora differently, providing additional reinforcement in resistance management. Furthermore, Fluopyram ensures a more vigorous crop, which in turn contributes to increased yield."
Finally, what is your spraying advice for 2026?
"Our advice remains to use 1,2 l/ha Propel "To start with, then alternate with another triazole, and then apply 1,2 l/ha of Propulse again as the third application. This might put Propulse on a pedestal, but we're willing to do so because we're convinced of its qualities, both in terms of foliar disease control and resistance prevention."
