“Spots appeared on the leaves of the cucumbers, then they dried out, and a little later holes appeared in these places. Is it a disease or a pest? What to do and how to process it?
This is not a pest, but diseasecaused by bacteria - bacteriosis. And it begins with the appearance of watery spots. Until these spots dry out and become clearly visible, not everyone pays attention to them. A little later, holes appear on the leaves of the cucumbers.
On a humid morning, droplets of bacterial exudate appear on the spots on the back of the leaf. In dry weather, the droplets dry out in the form of scales.
The central part of the spot gradually dies, the dried tissue discolors and many holes appear on the leaves.
On the stem and leaf petioles, the infection manifests itself in the form of watery spots. Fruits infected with bacteriosis in the ovary phase become deformed and dry out. Cucumbers infected at a later date rot.
The disease manifests itself after warm, rainy, windy weather. Bacteria spread with water droplets during cucumber care. They are stored in plant residues until they decompose. The source of the initial infection can also be seeds, in which the pathogen remains viable for about three years.
How to fight the disease
Measures to combat bacteriosis are preferable to agrotechnical ones.
- Maintain crop rotation and do not return cucumbers to their original place earlier than after 4 years.
- Destroy plant residues after the growing season. Dig the soil deeply.
- Avoid sprinkling irrigation.
- Choose varieties for sowing that are resistant to bacteriosis (this information can be read on the seed bags).
- Sow cucumbers in warm soil. Before sowing, disinfect seeds for four hours in a 1% solution of acetic acid.
- At the first signs of disease (the appearance of dry spots or holes on the leaves), the plants are treated with copper-containing preparations, but provided that there are at least 20 days left before harvesting.
- During the growing season, plants are sprayed with phytolavine (20 ml per 10 liters of water) against bacteriosis twice a month. The waiting period is 2 days.