What are pseudomonas and what damage do they cause to plants?

Pseudomonas can cause damage to plants

Image – Wikimedia / Luis Fernández García

Plants, as living beings, have their own defense system to protect themselves from viruses, fungi and bacteria. The problem is that, like humans, their health can be weakened. Cold, heat, thirst, hunger, and even the pruning that we do. Any stressful situation causes microorganisms to do their best to infect them, and among them we have the pseudomonas.

Although his name may not tell you much, you should know that are bacteria, to be more specific, gram-negative bacteria; that is, they have a double envelope made up of cells that protect their interior. They are also known this way because they do not stain dark blue or violet by Gram’s stain (it is a special dye that is used in bacteriology to see these microorganisms), but instead turn pink.

What are Pseudomonas?

Pseudomonas cause leaf damage

Pseudomonas cause leaf damage

The Pseudomonas are gram-negative bacteria that, thanks to a species of filaments called polar flagella, can move. They do not produce spores, but there are some species that do form a bacterial tapestry composed of one or more types of microorganisms and with a complex structure. Likewise, the secretion of a yellow-greenish fluorescent iron chelating compound is common in them.

Your metabolism is very diverse. This makes are microorganisms capable of colonizing a large number of living beingsincluding humans and also plants. Now, it must be clarified that not all Pseudomonas are pathogenic. For example, the Pseudomonas putida it is used as a biological control of plant diseasesLike Fusarium oxysporumas shown in this study posted on Taylor Francis Online.

Where are Pseudomonas bacteria found?

These bacteria they grow in practically any humid corner of the world. They can do it in swimming pools, in buckets that we use to collect rainwater, in tools if they remain submerged in water for a long time. We could even find them inside the house, such as in the bathroom or sink.

For this reason, and since they cannot be seen with the naked eye, it is very important that we wash our hands and disinfect the tools that we are going to use before pruning the plants, since otherwise we would run the risk of them becoming infected.

What plants do they affect?

Unfortunately, there are many to which they cause significant damage, such as the Pseudomonas syringaewhich affects a wide variety of plants, such as maples, legumes, lilac, peas, fruit trees such as apple or beet.

Still, if we don’t have any of those, we can’t let our guard down. Taking preventive measures never hurts. And it is that once the symptoms appear, it will be very difficult to eliminate the disease.

What are the symptoms?

Pseudomonas syringae affects plantsPseudomonas syringae affects plants

Image – Wikimedia / Jerzy Opioła

Bacterial canker or fire blight, as it is often called when it affects plants, is a disease caused especially by the Pseudomonas syringae. The symptoms and damages they produce are:

  • Appearance of yellowish spots (chlorotic) on the leaf, and in them we will also see small brown spots or spots that get bigger and bigger until they colonize the whole leaf.
  • The flowers will turn necrotic ahead of time, and they may fall.
  • Small black dots will appear on the fruitsat the same time that they are losing their natural color.

What is the treatment against Pseudomonas in plants?

What is most used are fungicides containing copper (as this). But in addition to that, it is recommended to apply natural biostimulants (for sale here!) to strengthen the immune system of plants. Of course, the instructions must be followed to achieve the desired effect. An overdose could be the end of the plant. Likewise, one must be applied first (we recommend that it be the fungicide), and after two or three weeks the other. They are not to be mixed.

Furthermore, it is also important to cut, with previously disinfected scissors, the affected parts whenever that is possible. In this way, we will slow down the progression of the disease.

How can it be prevented?

The first thing is to be clear that it is impossible to prevent, 100%, a diseaseregardless of what it is. We are talking about microorganisms that can only be seen through a microscope, and that are known to be affecting a plant when it begins to manifest symptoms.

But it is also known that, as with any disease, the risk of infection can be minimized by taking some steps. For the present case, these measures are the following:

  • Buy healthy plants
  • Water them and pay them whenever necessary, avoiding excesses
  • Disinfect tools before use
  • Cover pruning wounds with healing paste (on sale here!), especially if woody plants have been pruned
  • Keep diseased plants away from healthy ones
  • Use new substrates
Pseudomonas are pathogenic bacteriaPseudomonas are pathogenic bacteria

Image – Flickr / jacinta lluch valero

As you can see, Pseudomonas are bacteria that must be respected. That’s why I like to insist on one thing: disinfection. It will only take a moment, and you could keep your plant safe.

What are pseudomonas and what damage do they cause to plants?

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