Treatment, diseases

Botrytis: know, prevent and treat gray rot

Botrytis: know, prevent and treat gray rot

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Botrytis in summary :

Latin name : Botrytis cinerea
Common names : botrytis, gray mold, gray mold
Type : Mushroom

Whether in the orchard, vegetable patch or garden, the botrytis is a fungal disease who can tackle fruits, vegetables and plants whatever the stage of their development. Her speed of propagation and of growth, as well as its ability to subsist in the ground make it a tough opponent.

What is botrytis?

Botrytis or gray rot is an infection caused by mushroom Botrytis cinerea. The latter thrives both in the open air and in a greenhouse.

The mushroom Botrytis can tackle any plant tissue : leaves, stems, fruits, vegetables. As a rule, it benefits wounds associated with horticultural work such as leaf stripping, cutting, disbudding, etc.

The peaks in the spread and growth of botrytis occur mostly when the air has ahumidity level Student and that the temperatures are important (between 17 and 23 ° C). These conditions therefore make it particularly virulent during summer rains, as well as for greenhouse crops. The disease spreads much faster there because of the proximity of the plants.

Symptoms of botrytis

Depending on the stage of development and the infected area, the symptoms may vary.

Seedling botrytis:

Being able to be present from the development of cotyledons (leaves), either in the soil or with the seeds; gray mold can be the cause of damping-off.


At the start of the growth of the botrytis, the leaves show light brown spots, round and at the wet texture.

As they grow, they form concentric curves, then wither and this necrotic ; which can lead to the development of rot.

Disease extends so gradually for reach the rod, which it can then contaminate.


Stems attacked by gray mold show signs of cankers. The outer part of the rod then shows the same symptoms that the leaves with the beigeish color characteristic of the disease. The ultimate symptom, when stems are affected, is that they eventually see their leaves. yellow, se wither, se to dry out, then pass away.

Note that the stems are more sensitive to contamination thanthey suffer the most wounds (stripping, disbudding, cutting), which are all entry points for the fungus.


Botrytis can attack flowers and particularly inflorescences at the end of their life. They wither and then present a gray-brown appearance feature. Like the leaves, they are often the beginnings of a larger infection on the stems and on the fruits.

Fruits and vegetables and gray rot:

Symptoms on fruits and vegetables can manifest in two different ways:

  • the appearance of small white-yellow circles from 2 to 10 mm;
  • training on the basis of gray and soft rot, most often round as well.

Fight against botrytis

As with many diseases, the fight against botrytis occurs in two stages: prevention and, if necessary, the treatment.

Prevent the onset:

Like many infections, hygiene is often primordial and obviously applies to the plant world. A few simple steps can thus limit the spread of the fungus (even if they do not prevent its appearance):

  • disinfect tools between each cut;
  • eliminate cutting waste or dead plants;
  • avoid overcrowding greenhouses or shelters to limit spread;
  • ventilate confined spaces well to reduce humidity;
  • prune your plants more in the morning, in order to let the wound dry out during the day (the advice is also valid for watering by sprinkling);
  • avoid pruning when the weather is humid and hot;
  • Properly dose nitrogen fertilizers to prevent the leaves from being either too tender (excess nitrogen) or too weak (nitrogen deficiency).

Treat the disease:

Despite all of these precautions, it is not impossible that your plants can be affected by the disease, and when botrytis has appeared it is difficult to control. Indeed, it has a ability to adapt quickly to fungicides. In addition, the latter are too few to allow effective control by alternating active ingredients in order to avoid the appearance of resistant strains.

There are however some phytosanitary solutions to fight against botrytis. You can find them on the ephy.anses website, in the research section by typing the keyword “gray rot” in the “Pest / Disease” section.

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