Botrytis cinerea or gray rot

Today we are going to exchange plants and crops for the organisms that attack them. One of them, very important, is  Botrytis cinerea ,  a pathogenic fungus that “loves” to lodge in all kinds of plants. As a curiosity in this introduction to tell you that it also does it in animals and bacteria, so it is an example of the natural evolution of species. We are going to meet this controversial mushroom.


Although its scientific name is somewhat difficult for those who have not had direct contact with this disease, the name ” gray rot ” or ” gray mold ” will surely be familiar to you .

However, you have to specify something technical and particular to the world of fungi and that is that, to put it in some way, this disease is not always called the same. Botrytis cinerea is so called when the fungus is in anamorphic form, but it is also called  Botryotinia fuckeliana  in its teleomorphic form (also  Botrytis vulgaris ). 

STOP   We are going to explain this of the phases or forms:

  • Anamorph: it is an asexual reproductive state in which anamorphs occur. To further curl the curl, when these anamorphs are not the same it is called sinanamorphs.
  • Teleomorph: it is a sexual reproductive state.
  • Holomorphic:  when the fungus is developed, including its anamorphic or teleomorphic state.

For this reason, the most famous is cinerea , in its anamorphic form, since it is usually found in asexual form. uckeliana,  which also exists, that almost comes to the same thing, would be more rare and unknown sexual way.

Although we can see this fungus in many crops, it is especially feared on the vine. In fact, the term botrys  means bunch or group of grapes . The term  cinerea comes from  ash , and is that, as we will see later in the identification, a grayish dust appears as if it were ash.

Botrys + cinerea = bunch of grapes with ash

It seems a lie, but we who have coe out of pure sciences are surprised by this from Greek and Latin 🙂


From a biological point of view, this fungus has many conidia . These conidia are asexual spores and a means of propagation of the fungus. Hence the expansion and growth of this fungus is so important.

In fact, it can occur in almost any part of the plant, be it the stem, leaves, fruits, etc. The mode of entry is through wounds, so you have to be careful with pruning, mechanical damage, etc. Even being careful in the agricultural work, the horticulturist will never be safe from his plants being infected by Botrytis cinerea , since the means of entry does not have to be very large. A rub, crack, hail damage, an insect bite, or anything similar may be enough.

As for the temperature, it does not have to be high, as this would suppose a future dryness that is not beneficial for the fungus. A temperate or warm climate with high humidity (for example, with heavy watering, rains, etc.) is enough to provide an incredibly beneficial environment for this fungus, which will spread very easily.


This fungus is a problem and a great headache for vine growers and, in general, wine producers, in all production phases, not only in agriculture.

What this fungus basically does is dry the grape. By eliminating the water, the grape is much more concentrated in sugars and solid elements. The result is a grape with more flavor and more concentrated that, although it may seem like it, is not ideal, since the flavors are not balanced.

And if we talk about the entire winemaking process, Botrytis cinerea also affects fermentation, since it secretes an antifungal (pure competition for space …) that loads the yeast , so the fermentation process stops before it has the degree of alcohol required.


As we have said, Botrytis cinerea is not only a grape disease, it also attacks a large number of plants, including horticulture.

We can see affected crops such as grape, pepper, strawberry, tomato, apple, pear, onion, citrus and a very long etcetera. Rot is practically a common disease in many harvested plants and fruits. The spores are easily transmitted when the temperatures are pleasant and the lighting and ventilation is not very good (be careful with crops with very high densities).



  • Avoid unnecessary cuts or wounds on the plants. Treat wounds with protective gels.
  • Protect crops from frost or heavy rains.
  • Control watering and do not wet parts of the plant if the weather is not good.
  • Improve ventilation and increase sowing or planting density.
  • Use clean and disinfected tools (scissors, saws, box cutters, etc.).
  • Remove infected plant parts or the entire plant if there is a risk of spread.

The solarization technique ( discussed in this article ) is a good, totally ecological way to disinfect the soil if we detect that previous crops have suffered attacks from this fungus.


Chlorthalonil 72% (720 g / kg) , a broad spectrum fungicide that is widely used as a preventive action (after rain, for example). It is usually applied in many horticultural sonaláceas such as pepper, tomato and aubergine, and works very well with celery, onion, leek, garlic, strawberry, bean and many ornamentals.

Cyprodinil 37.5% w / w (375 g / kg) and Fludioxonil 25% w / w (250 g / kg),  a very effective fungicide against this fungus since it acts through two different active ingredients. It inhibits the production of spores, the growth of the fungus and prevents it from entering the plant (where its elimination is more complicated) through its mycelium.

It can be used with a large number of cucurbits, beans, aubergine, tomato, pepper, strawberry, grape, etc.

Fenhexamide 50%,  a fungicide from the hydroxyanilide family that is very effective against Botrytis cinerea,  since it is responsible for inhibiting the production of the germ tube.

It is applied to strawberry, raspberry, tomato, pepper, eggplant, cucumber, zucchini, bean, etc.


You have to take into account the date on which this article was written and its verification with the list of authorized subjects according to the country in which you are.

When in doubt, consult a specialist.


Although they are not as effective as chemical products, the use of good agricultural practices , coupled with correct fertilization or irrigation and products of an ecological nature, can control  Botrytis cinerea .

There are some fungi that emit antifungal substances (as does Botrytis ) to prevent their growth and spread. For example,  Mucor spp.,  Penicillium spp.,  Coniothyrium spp.,  Verticilium spp.,  Trichoderma spp., Etc. ).

Bacillus subtilis (strain QST 713).   It is applied as a normal spray on a large number of affected crops. It is usually applied in a volume that varies between 500 and 1,000 L / ha (you have to make accounts to pass it to the measurements of your orchard or garden area). As it is awettable powder,between 2.5 and 4 kg / ha are applied for crops such as tomato, aubergine, pepper, strawberry, etc.


It is based on the use of plants that have some antifungal action, and that we have already talked about some in plant extracts . Its power of action against Botrytis cinerea is limited, and it is usually used more as a preventive than as a fungicide, but it can save us from more than one hurry if we want to take our garden in an ecological way.

  • The garlic extract has some extenuating power in the development of gray mold in strawberries.
  • The thyme extract has been studied for its positive effects on limiting the development of this fungus.
  • Lemon leaves (essential oils citral myrcene, dipentene, etc.) have some antifungal power.

If you know of any other remedy against Botrytis cinerea , put it in the comments or on the forum.

Leave a Reply

Your email address will not be published. Required fields are marked *