7 terrifying reasons why Xylella fastidiosa is so dangerous

Ever heard of Xylella fastidiosa? It is one of the most threatening pathogens to global plant health and agriculture. Just take a look at the aftermath caused by Xylella fastidiosa in southern Italy in the picture below. It is without a doubt of the worst and most deadly pathogens, and that’s why it deserves our undivided attention.

xylella fastidiosa

Image credits: © Dr. Pasquale Saldarelli – CNR

What is Xylella fastidiosa?

In short, Xylella fastidiosa is a plant pathogen which is transmitted by xylem feeding pests such as Philaenus spummarius (commonly known as the spittlebug). Once the insect starts feeding off the xylem fluid (plant sap), the plant gets infected from the bacterium transmitted by the insect and from there everything starts spiralling downwards. Subsequently, what happens next is that the plant starts to die from inside out, as if it was drying itself or starving itself from within.

This is what initially causes the plants to wilt and lose their vigour once the plant is infected. After some time, the plant starts to showcase severe symptoms which eventually lead to plant death. It is always just a matter of time.

This is exactly what makes this pathogen so dangerous. It keeps spreading and there is no cure. Once the plant is infected, it’s game over for the plant. Hence, finding a cure for Xyllela fastidiosa has never been more important. It is so important, that it has been added to the list of EU’s top 20 priority pests.

7 reasons why Xylella fastidiosa is so dangerous

1. There is no cure for Xylella fastidiosa

global threat of xylella fastidiosa

Image credits: © Shutterstock

No. Unfortunately, as mentioned above, there is also no cure for Xylella fastidiosa. Not yet anyways. Since there is no cure, it has caused extreme devastation in southern Europe, especially in Apulia (Italy). Centennial trees have been completely destroyed. Newly infected regions unfortunately share the same fate unless EU science finds a cure!

Hence recognising the threat of Xylella fastidiosa is extremely important if we want to sustain our future and achieve a green recovery of Europe.

2.  Symptoms are misleading

symptoms of Xylella

Image credits: © Shutterstock

Xylella fastidiosa symptoms are known to be quite misleading. Oftentimes, people misidentify the symptoms for classic cases of plant dehydration or simply think that the plant has had too much sun. Nevertheless, leaf scorching and wilting is just the beginning. These mild signs of the infection often lead to more severe symptoms such as dieback and leaf abscission.

That’s when you’ll know that the pathogen has really kicked in and that there is no turning back. The nutrient flow of the plant becomes completely blocked and the plant starts to die slowly from within.

If you suspect that your plant may have Xylella fastidiosa, you will need to make a test. Even mild symptoms can be early signs of something more severe!

3. Almost 600 types of plants are at risk

xylella fastidiosa symptoms

Image credits: © AIMERIT SL

Not all plants are affected by Xylella fastidiosa. However, there are almost 600 species of plants which are at risk of being infected with Xylella fastidiosa or being potential hosts. These types of plants include a variety of olive trees, lavender, oleander, ash, and many more. That’s what makes Xylella so dangerous as it affects a variety of plants.

Luckily, there is a database which identifies species of plants which host Xylella fastidiosa. Click here to view the database, especially if you suspect that your plant may have Xylella. It is best to first identify whether the plant even belongs to the species list before panicking. If it does, you will need to alert your local plant health authorities so that they can conduct appropriate tests to determine whether your plant has been infected or not.

4. Infections spread fast across Europe

threat of xylella

Image credits: © Shutterstock

Xylella infections spread fast. Xylella fastidiosa was first identified in Italy, most notably in the southern region of Apulia. Since 2013, it was found in Portugal, Spain, France and even in Germany (although it has since been eradicated). Just recently, Xylella fastidiosa has been reported in Occitanie for the first time, proving that the infection is still spreading at a fast rate.

In fact, Xylella fastidiosa spreads approximately 2 km per month in the infected region. For this reason, new legislative measures were put in place by the European Commission as means of controlling the quick rate of new infections.

5. EU measures introduced to contain the infections

Xylella in France

Caption: Xylella fastidiosa in Occitanie – 2.5 km containment zone around Trèbes at 7km from Carcassonne| Image credits ©Préfet de la région Occitanie

The fact that the European Commission introduced EU regulations to prevent the introduction and spread of Xylella fastidiosa is evidence that Xylella is very dangerous to Europe. Places where Xylella have been found must undergo a containment zone, in compliance with EU Regulation 2020/1201.

Infected plants must be uprooted or destroyed by means of burning them. Now take a moment to imagine a farmer having to intentionally destroy a magnificent 1,500 year old olive tree.

6. Negative effects on the economy

threat of xylella in Europe

Image credits: © Shutterstock

Xylella fastiodosa has severe agro-economic repercussions in the region where infections are borne. Just this year, the production of olive oil decreased by a staggering 26% in Italy as compared to 2019 due to Xylella, as stated by The Guardian.

On top of that, thousands of jobs have been lost on the account of farms and nurseries being abandoned.

As the number of new Xylella fastidiosa infections grow in the Mediterranean region, the amount of olive oil produced is expected to decline more.

7. Priority amongst EU science & research

xylella fastidiosa

Image credits: © Shutterstock

As regards sustaining and protecting global plant health, Xylella fastidiosa has been identified as one of the top 20 priority pests by the European Commission. This showcases the severity of the pathogen.

In response to the Xylella outbreak, the European Commission funded multiple actions to combat the problem of Xylella fastidiosa. These include projects such as XF Actors, COST, PonTe, CURE XF, Life Resilience and BIOVEXO.


BIOVEXO is an EU-funded innovation action, which demonstrates a set of novel biopesticides for curative and preventive cases for Xylella fastidiosa and its vector. The consortium will test a set of six candidate solutions.

What are your thoughts on Xylella fastidiosa?

Do you think EU science will find a solution to this dangerous problem soon? Let us know in the comments section below.

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