Spinach Diseases: Leaf Spots, Viruses, and More

Hello to all agrohuerters! In previous articles we have already seen what the most important pests of spinach were. To complete this information, in today’s article we will see which are the spinach diseases that are most common in the garden.

Of all of them, we can anticipate that diseases caused by fungi are the most common. These diseases include: Alternaria, Botrytis, Cladosporium, Cercosporiosis, Mildiu, etc. These types of spinach diseases are very similar to those of the beet crop.

White spots on spinach leaves

If we observe white spots on spinach leaves, it may be due to various diseases. Among them are: Oidium or cladosporiosis.

We have already talked about powdery mildew on other occasions. One of the most characteristic symptoms of powdery mildew is the presence of white powder on the leaves of the plants. Over time, this white powder will spread over the leaf surface. Powdery mildew is a fairly common disease in other crops as well. For example: in cucurbits, such as pumpkin (Cucurbita maxima duchesne), courgette (Cucurbita pepo), melon (Cucumis melo) or cucumber (Cucumis sativus).In addition, it can affect other vegetables, such as beans (Phaseolus vulgaris), chard (Beta vulgaris)or the potato (Solanum tuberosum).

Cladosporiosis is a fungal disease caused by Cladosporium variabile.It is identified by causing small round white spots on the leaves. This disease is spread through seeds, wind or rain. If it rains and it is cool, it will be an opportune moment for this fungus to enter our garden.

I leave you here a photo of this disease to help you recognize it in the future.

Dark spots on spinach leaves

If, on the other hand, what we see on our spinach plants are darker spots, it may be due to other types of diseases such as Cercosporiosis or Anthracnose.

• If the spots are round and surrounded by a reddish halo, it may be a disease known as Cercosporiosis.
• If the spots have a necrotic appearance and evolve until they occupy a large part of the leaf surface, it may be Anthracnose. Anthracnose is due to a fungus known as Colletotrichum dematium. It is a fairly common disease in this crop.

Yellow spots: downy mildew on spinach

Mildew is one of the most characteristic and frequent diseases of spinach. It is characterized by causing chlorotic spots on the upper face of the leaves and a grayish mold appears on the underside. This deterioration of the leaves occurs very quickly.

This disease is due to a fungus known as Peronospora farinosa and can appear in both spring and autumn. It usually appears when the environment is humid and dim. It can be transmitted through wind and seeds. Also, the spores of this fungus can survive in the soil for many years.

All stages of spinach cultivation are susceptible to a mildew attack. Especially the young leaves are the most affected.

There are also other types of light brown spots that can be caused by Alternaria.

spinach virus

In addition to fungal diseases, our spinach can also be affected by viruses. One of the most important viruses of this crop is the cucumber mosaic virus (Cucumber mosaic virus, CMV).This virus can be transmitted through aphid bites (non-persistently) or through infected seeds.

Some of the most characteristic symptoms of cucumber mosaic virus are plant growth arrest and deterioration of spinach leaves. A kind of mosaic appears on the leaves that causes a yellowing of the same.

In addition to this virus, there may be another virus known as Beet mosaic virus (BMV). This virus can also be transmitted by aphids when they bite into leaves.

Growing organic spinach: organic remedies against fungi

Once we know how to identify the main diseases of spinach, it is necessary to learn how to control them with ecological remedies. To do this, we will see different prevention and control methods that you can use in your orchards and gardens.

Prevention of spinach diseases

As always, I remind you that the prevention methods are those that will help us prevent the appearance of spinach diseases. Among all the preventive methods that exist, the most important are listed below:

• Crop rotation
• Using disease-resistant varieties will help us reduce the risk of them appearing on our plants.
• Control the irrigation system to avoid possible flooding or irregular irrigation.
• Monitor the presence of aphids to avoid further transmission of viruses.
• Eliminate weeds as they can also dispose of many diseases.
• Disinfect materials used with diseased cultures.

Organic Spinach Fungus Remedies

Once we have seen how to prevent spinach diseases, we are going to see how to control them with organic remedies.

• Regarding the control of diseases, I encourage you to consult the article on how to make homemade fungicides. In the article you will see how to perform each of the methods step by step.
• Against mildew we can use sodium bicarbonate, Bordeaux mixture or potash soap.
• Remove the most damaged leaves to prevent the disease from spreading to other plants in the garden.

References

• Patriarca, A., Fernández, V. (2018) Alternaria. Reference Module in Food Science, Elsevier.
• Koite, S. Y.; Gladders, P., Paulus, AO (2007). Vegetable diseases. Academic Press. San Diego.
• Correll, JC; Morelock, TE; Black, M.C.; Kolke, T.K.; Brandenberger, LP & Dalnello, FJ 1994. Economically important diseases of spinach. Plant Disease 78, 653-660.
• Li J, Liu X, Yang X, Li Y, Dexian C (2018).Proteomic analysis of the impacts of powdery mildew on wheat grain. Food Chemistry, 261, 30-35.