Treatment of downy mildew of cucumber

If we notice yellow spots on the cucumber leaves, our crop has probably been affected by the downy mildew disease.

Powdery mildew, along with cucumber powdery mildew and carbonization, are the most important fungal diseases of cucumbers, causing serious damage to outdoor and greenhouse crops.

In addition to the cucumber crop, downy mildew also attacks other cucurbit crops such as the squash crop, the pumpkin crop, the gourd crop, the melon crop and the watermelon crop.

It is important to recognize the symptoms of powdery mildew early so that we can fight it effectively.

In today’s article we will describe the characteristic symptoms and the damage caused by downy mildew on cucumbers and cucurbits, as well as the ways in which it can be biologically treated.

1. What are the symptoms of downy mildew in cucumber and cucurbits? Downy mildew of cucurbits (Pseudoperonospora cubensis) is initially found on the surface of the leaves with the appearance of round or angular yellow spots. In some cases, the initial symptoms on the leaves are very characteristic, as light green areas are formed that resemble a mosaic appearance. In conditions of high humidity, on the lower surface of its leaves, whitish fungus fruitings are formed which gradually turn black.
2. What damage does downy mildew do to cucumber? Downy mildew causes severe damage to cucumber, as diseased leaves gradually dry up and fall. Leaf blight infestation has a significant impact on cucumber growth and can prevent crop destruction. In conditions of severe attack by downy mildew, cucumber plants become very weak and eventually dry out.
3. What conditions favor the spread of downy mildew in cucurbits? The development of the downy mildew disease is favored in humid environmental conditions and when the leaves remain dry for a long time. Cucumber downy mildew is caused by both high and low temperatures as long as it is moist, which is not the case with other horticultural pests such as potato downy mildew. When the temperature exceeds 30°C, the spread of downy mildew disease in cucumber plants is prevented.
4. How is the biological treatment for downy mildew in cucumbers and cucurbits? To deal with downy mildew in cucumbers and cucurbits, we make sure to ensure conditions of reduced humidity and good ventilation, avoiding dense plantings. When we notice the first symptoms of downy mildew on plant foliage, we make sure to immediately remove the affected leaves to limit the spread of the disease. In addition, to fight downy mildew of cucurbits in a biological way, we preventively spray the leaves of the plants with liquid copper preparations.
5. And a secret for treating downy mildew. Each variety of cucurbits shows different resistance to downy mildew. There are several varieties of cucumber, squash, watermelon and cantaloupe that are much more resistant to downy mildew and are available on the market.