In July, it is important to pay attention to the disease in sugar beet – CERCOSPORA
Leaf health plays an important role in beet growing. Only a healthy leaf apparatus allows the genetic potential of sugar beet to fully unfold. Green leaves are responsible for collecting solar energy and sugar.
►Solar energy collection, product formation, sugar formation;
►Fungicide application reduction, savings on drug;
►Natural replacement of leaves without loss of yield and sugar;
►High quality (low K, Na and alpha-amine nitrogen);
►It means that there are no foci of infection in the soil due to the absence of fungal spores in plant residues (leaves) after harvest.
In recent times, the level of infection of sugar beet with cercospora, ramularia and powdery mildew continues to increase. Recent hybrids of sugar beet are characterized by the optimization of plant height. Although they produce few leaf apparatus, they have high yield and sugar yield. At the same time, the application of optimal amount of nitrogen also leads to the formation of fewer leaves. Diagnosis of leaves during the growing season is very important for planning optimal disease control measures.
One of the main diseases to watch out for in July is Cercospora.
- Cercospora beticola
- On the leaf, it appears in the form of circular spots, 2-3 mm in size, the edges of which are bordered by a red-brown ring. Light gray areas with black dots are observed in the center of the spots.
Similarity with other diseases
- Bacterial leaf spot
For optimal development
- Air temperature -23-270C
- Relative humidity -96%
- Rainy and hot weather
- Row closing period
Image. 1-2 - initial stage, 3 - later stage
Under the microscope, cercospora looks like this
In severe infection with Cercospora, the spots grow and coalesce, resulting in drying along the entire surface of the leaves, resulting in the death of the leaf. At first, the infection occurs on individual leaves, and with its spread, disease foci appear in the field. Fungal spores are preserved in soil with dead plant remains. Symptoms appear 5 days after infection when air temperature is 23-270C and humidity is 96%.
Despite the destruction of the leaves, new leaves begin to form in the damaged plant. The formation of new leaves takes place by consuming the sugar inside the root. As a result, the process of sugar reduction (loss) occurs in beets.
Formation of new leaves
As a special control measure, the selection of cercosporia - resistant hybrids is the identification of the disease in the initial phase by regular monitoring in the field and the use of drugs against it. Another control measure is preventive medication against the disease in periods when it is likely (on the basis of forecasts).
Medication of sugar beet
Image. The times of treatment of sugar beet with fungicides depending on the degree of harmfulness of various diseases
Treatment with fungicides is extremely important in the following cases:
- In July, 5 out of 100 leaves were damaged in the field:
-At the beginning of mid-August, 15 out of 100 leaves were damaged in the field:
-After August 16, 45 out of 100 leaves were damaged in the field:
If the 1st medication was carried out in July, it is important to carry out the next medication in early August if 45 out of 100 plants are damaged.