Some websites with valuable information on OQDS:
http://nature.berkeley.edu/xylella/ Photo and other information about the Xylella fastidiosa bacteria;
http://nature.berkeley.edu/xylella/insectVector/geninsct.html Photo and other information about the Xylella fastidiosa bacteria;
https://microbewiki.kenyon.edu/index.php/Xylella_fastidiosa Photo of bacteria;
http://www.nytimes.com/2015/05/12/world/europe/fear-of-ruin-as-disease-takes-hold-of-italys-olive-trees.html pictures of trees
http://phys.org/news/2015-12-italy-prosecutors-halt-felling-olive.html
http://www.oliveoiltimes.com/tag/xylella-fastidiosa?page=3
https://www.google.com/search? Many photos of trees with Olive Qick Decline Syndrome (OQDS);