Leaf fungi in sugar beets

The weather conditions and the condition of the crops make it necessary to increase vigilance for leaf mold in sugar beets. Guus Bergmans from BASF shares his view on the current situation and the desired approach to the fungi.

"No, the IRS has not yet issued any warnings," says Guus Bergmans of BASF. "There is therefore no acute situation. But there is every reason for sugar beet growers to increase vigilance in the coming period." Bergmans is referring to various factors. "The weather recently has been favorable for several fungi. The cercospora and mildew are in their element at the higher temperatures of the last few days. The temperatures of the period before and the coming week are again favorable for rust and mildew And with the exception of mildew, all fungi love moisture. And we have had enough of that. So all fungi have had or will soon have opportunities to develop microclimate for the fungi."

Moderate condition
A second factor that plays a role is the poor condition or backwardness of some beet plots. Bergmans: "The better a plant grows, the more resistant it is to fungi. But with the recent cold and precipitation, growth has been at a low level on many plots. That will have influenced the susceptibility of the sugar beets."

There is also a threat from another source, namely the fungi themselves. "Due to the poor harvesting and weather conditions last autumn, many more crop residues were left behind. In places, even entire plots were not harvested," recalls the technical product advisor. "Fungi such as cercospora could easily overwinter there. And Cercospora apii, another variant of this fungus, also overwinters on all kinds of weeds. Enough reason to be alert."

Effective approach
According to Bergmans, it is especially important for the coming period that growers closely monitor their sugar beet plots themselves, for example with BAS, and follow the warnings and mold information from the IRS. "There have already been days with a high infection rate for cercospora throughout the country. This has not yet led to any warnings, but it shows that the fungus does have opportunities."

For a targeted and effective approach to leaf fungi, timely first spraying is very important, says Bergmans. "The cercospora is by far the most important fungus. Spray as soon as you find spots yourself or when the sensor in your area shows a high infection value for two days in a row. Our new fungicide Diadem is an excellent candidate for that first spraying. It has two active substances, one of which is from a new group for sugar beets. This provides extra security from the point of view of resistance development. And Diadem is effective on all leaf fungi in sugar beets.

The moment for the first spraying with Diadem is determined by observation and advice. The interval for subsequent sprayings depends on crop growth and disease pressure. Promoter promotes fungicide uptake under dry conditions.

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