- The bacterium 'Candidatus Arsenophonus phytopathogenicus' is considered to be the cause of Low Sugar Syndrome.
- Affected plants have a lower sugar content by approximately 2-5% absolute value.
This is a completely new disease, not yet well known to scientists. The literature shows that the symptoms of infection are quite specific. Visually, the beetroot roots do not show any disease problems, they are firm and without damage. However, in the cross-section, a brown color of the conductive bundles is observed. The leaves turn yellow, but do not lose turgor because of this. However, they take on a lanceolate shape.
According to scientific reports, the main visible damage is marked yellowing and chlorosis of older leaves while the leaf veins remain green
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CR+ varieties provide effective protection against the beetroot weevil
According to IOR-PIB in phytosanitary reports, SBR syndrome was first observed in eastern France in 1991. In the following years in Hungary, Germany and Switzerland. It currently occurs in many European countries. In 2021, approximately half of the sugar beet cultivation area in Franconia (Bavaria, southern Germany) was affected by SBR.
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Numerous spider mites in sugar beet. The heat favors them
Another bacterial disease
However, according to IOR-PIB, in 2023 rubbery, deformed beets were diagnosed in Germany in northern Bavaria. It has been proven that the Stolbur bacterium, i.e. 'Candidatus Phytoplasma solani', is responsible for such symptoms. It mainly affects nightshade plants, but in the case of rubber beets, the sugar content in the roots does not decrease and may even increase. However, the yield of such plants drops rapidly and they are unsuitable for storage.
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Dynamic development of the tassel. However, not every spot on the leaves is a tassel
The vectors of bacteria are bugs
The disease vectors of both 'Candidatus Arsenophonus phytopathogenicus' and the phytoplasma 'Candidatus Phytoplasma solani' are hemiptera, also known as cicadas. In Germany, the most common vectors are two species of leafhoppers: Hylalesthes obsoletus and Pentastiridius leporinus. The second of these, called the reed cicada, also occurs in Poland and is considered the main vector of bacteria currently threatening sugar beet crops.
Combating it is very difficult
Infected roots are practically impossible to cure due to their bacterial nature. The only option is to fight the jumpers. However, there are no registered insecticides for beet cultivation, so they can be combated when other pests occur on the plantation. Moreover, jumpers move easily. According to scientists from IOR-PIB, preventive measures include the use of appropriate crop rotation, in this case avoiding sowing winter wheat after beets. Wheat is exceptionally favorable for the development of leafhoppers. Replacing it with spring barley can reduce the number of insects.
