Downy mildew, rust, powdery mildew…This week, our gardener Jérôme is warning you once morest the diseases that can affect your plants. He will also tell you how to grow celeriac.
Heat waves, storms… the weather is particularly conducive to the development of diseases. One of the main causes, the dreaded mushrooms.
Once landed on a plant, they develop microscopic filaments inside their host. This slows down its development and can even lead to the denaturation of the harvested parts and the death of the plant.
The mushrooms
Sudden variations in temperature and humidity, and in particular stormy summer days, favor the development of fungi. The same applies to excess fertilizer, watering and, in greenhouses, damp heat.
A few preventive measures can limit the risks:
- Keep your crops well ventilated so as not to form humid microzones which will be so many sources of infection. For this, plant and sow wide, carefully thin out your seedlings in rows.
- Avoid sprinkler watering, opt instead to water by foot or drip for wide-spaced crops. And above all, do not water in the heat.
Do not over water
The main diseases caused by fungi and common to several vegetable plants are mildew, powdery mildew, rust, botrytis.
Downy mildew attacks potatoes and tomatoes, but also cabbage, spinach and onions. Its symptoms: yellowish-white spots appear on the upper side of the leaves, with purple-white felting on the underside – then bumpy brownish spots on the fruits or on the tubers.
Thank you Bordeaux porridge
Preventive sprays of Horsetail decoction strengthen the plants. And Bordeaux mixture sprays are effective if they are done early.
Rust mainly affects liliaceae (garlic, leek, onion, asparagus). Yellow to brown pustules appear and the leaves take on a rusty appearance and then dry out. Here too, Bordeaux mixture should be used.
celeriac
Its cultivation is often considered difficult. The easiest way is to buy seedlings in plugs from a producer.
They are planted 15cm apart in rows 40cm apart. They must be buried as little as possible so that the root ball can grow.
During its development, the outer stems are removed to favor new ones which will enlarge the root. It is necessary to mulch well and water regularly
