Bacterial Infection of Olive Trees in Southern Italy

[ths907]

In case of interest, here is a blog in English covering the invasive bacteria, Xylella fastidiosa, killing olive trees in southern Italy: Diffusion of xylella in Italian olive trees .

EU-imposed quarantine measures are currently on hold.

[David Humphries]

Thank you for posting

 

 

 

 

.

[treeseer]

I hope their preemptive killing is on hold too!

[farmer rod]

Thank you for posting

 

 

 

 

.

 

Maybe a daft question, but can trees be inoculated or immunized ?

[David Humphries]

Maybe a daft question, but can trees be inoculated or immunized ?

 

I don't know the answer to that.

 

Looking at the linked blog above, grafting of disease-resistant varieties has been tried, but I'm not sure how successful or sustainable that's been.

 

I'm going to Italy in A couple of months for a workshop on the management of Ceratocystis, hopefully we'll get the opportunity to learn more about Xylella also.

 

 

 

.

[Jake Andrews]

http://www.bbc.co.uk/news/science-environment-35917107

This might answer some questions.

[Kveldssanger]

Some resistance is good, but as Xylella also has many sequence types (genetic 'strains') there is no guarantee that the pathogen itself won't evolve to trump the resistance of the resistant olives. Furthermore, is the resistance passed on via clonal propagation, or can it be retained via sexual breeding of a crop?

 

In fact, this isn't resistance but tolerance. Damn BBC getting it wrong, there. Tolerance doesn't equal resistance. Is this tolerance situational, and is it tolerance to a specific ecotype / sequence of Xylella? As Xylella can (from what I have read) exist as an endophyte, what's to say that it cannot remain latently present, respond to conditions within the host plant / tree, and still retain its pathogenicity for a time when it will be better-suited to pose a threatening attack upon its host?

 

Good news, but we 'aint even started making the cake yet with this one. We don't even have all of the eggs needed. Can someone go out and buy some icing sugar?

[edwood]

Interesting stuff, I spend a fair bit of time down in southern Italy as my

Mrs 's mum and dad have a place down their right in the olive groves.

 

These guys seem to really hammer the trees down their, they remove pretty much all the crown, they rake all the leaves/dust up and then go along with a roller and compact all the soil underneath so it's rock hard and weeds don't grow and continue this process almost yearly, doing the crowns on say a 5 year rotation. I've always thought that surely all of these trees must be in a pretty weakened condition and vulnerable to an issue like this

[Kveldssanger]

Good points you raise, there. A possible lack of mycorrhizae, energy reserves within the tree, and a lack of plant diversity ensures pathogens can have a field day (no resilience).

[Quercus Robert]

Isn't this issue strikingly similar to the plight of ash trees? I.e., weakened trees succumbing to a pathogen.