Farmers

The Need to Take Measures to Fight Diseases

1.Last years, significant changes in the leaf apparatus began to be noticed already at the beginning of July on all fields cultivated with sugar beet, fact that results in the cessation of the sugar beet growth dynamics and in the reduction of the content of sugar. The changes in the leaf apparatus are influenced not only by the dry weather and high temperatures, but also by previously unknown diseases, which attack the plant. Using the experience of European farmers, SÜDZUCKER MOLDOVA, assisted by the Department of Raw Materials and agro-consultants, applied the following fighting measures in 2003:

• Raising the awareness about the main diseases, such as “cercospora beticola”, “ramularia”, and “powdery mildew”.
• Establishing the damage threshold by means of "MONITORING-FRUNZA".
• Training and practical support on using fungicide in households. 

2. Short Description of Disease Signs

Cercosporosis - lat.(Cercospora beticola)

Beginning of the disease: round or elongated grey spots with brown or red edge. Cause of the disease: Cercospora fungi. Late stage of the disease: the spots join having dark edges and grey mycelium.

Black spores can be seen under the microscope!

Ramularia - lat. (Ramularia beticola) 

Beginning of the disease: chaotically located spots of 3-8 mm diameter, their center is darker, while the edges are lighter, not very visible. Late stage of the disease: the spots join in larger lesions. Most often, the affected fibers of the plant are breaking.

Light spores can be seen under the microscope!

Powdery mildew - lat. (Erysiphe betae) 

Beginning of the disease: the internal and external part of the leaf are covered with a thin layer of white fungi. Late stage of the disease: the leaf fades and dies. Within the last two years, sugar beet harvest has decreased by 40 centners /ha and sugar content by 1.5% because of leaf apparatus diseases.

3. Determining Disease Stages:

The fight against disease depends on the nature and intensity of the disease. Most often, the disease is found in 5% of plant leaves in July. At the beginning of August, 15 % of plants are affected by diseases, while in the middle of August – 40-50% of them are affected!

4. "MONITORING-FRUNZA" (Leaf Monitoring) as a method of determining the period of fighting diseases

 The field is divided diagonally and one leaf of any sugar beet is torn at each 5-10 meters.

1. The leaf is torn from the middle well developed part of the leaf apparatus. On the whole, 100 leaves are torn and placed in a plastic bag.
2. The leaves are gathered randomly from the middle part of the leaf apparatus.
3. Each leaf is studied to determine whether it is affected. The number of spots is calculated. Equivalent: one spot – one affected leaf.
4. The number of affected leaves is written in the record form (“Field Mirror”)
5. Fungicide spraying must be applied when the stage of affections comes (fighting diseases).

 By August 15: The spraying must be done in case 5 affected leaves are found and the spraying must be continued.

After August 15: if 40-50 leaves are found.