Why We Should be Concerned About Olive Tree Diseases

Olive fly Bactrocera oleae and the bacteria Xylella fastidiosa are serious concerns for olive growers. Tearing down thousands of olive trees because of disease is devastating for the   environment.

 I recently talked to Fabienne Maestracci a talented olive grower from Bonifacio the southernmost tip of Corsica. We talked mostly about her winning both gold and silver medals for her harvesting of Corsican olive oils. Understandably, she was thrilled to win the awards but what I found alarming was the fear she expressed over the dreaded Xylella fastidiosa.   The disease was  spotted for  the first time near her orchard around this time last year causing   great concern in France’s Isle de la Beauté . Thankfully the infected plants were destroyed.  

 However, Fabienne feels that “the danger would always be there” and says  that more can  be done to control plants being imported. It seems Xyella fastidious came to Europe via an infected plant that came  from Costa Rica.

Olive growers already have the olive fly to worry about.  Known as Bactrocera oleae, the invasion takes place when the female olive fly lays its eggs in the fruit, just under the skin. The fruit rots fall to the ground prematurely and cannot be used.   Olive growers know that if they don’t adopt a reliable fruit control program they can easily lose all their fruit. To make matters worse, these last few years we’ve been having mild winters and humid summers ideal thriving conditions for the olive fly.

Xylella fastidiosa is different.  There  is no known remedy for this  plant bacteria classed as one of the most dangerous in the world. It attacks citrus fruits, olive trees, grape vines and a lot more plants. Although not dangerous to humans, once the disease is established, it starts infecting other plants. 

We first heard of the disease in Europe in 2013 when it caused widespread devastation in Southern  Italy then later in 2015 in France.  To combat the disease, Italian farmers had to chop down their olive trees; to prevent the disease from spreading they were forced  to destroy thousands of ancient olive trees.

If we keep doing that though  we'll have  an environmental problem. Although the  European Parliament is  doing its  best to keep the disease at bay,  this is a problem for everyone everywhere: for gardeners, horticulturists, as well as consumers of extra virgin olive oil. Lovers of exotic plants have to be more careful what they bring back into the country and also what they order on the internet.

As the International Olive Oil Council says “Given the natural capacity of olive trees to store atmospheric CO2 in the soil, our message could be ‘that olive oil is both healthy and good for the environment.'

Let’s try to  keep it that way.