This is one of the most serious soilborne fungal pathogens. It doesn’t just damage; it kills young and old olive trees alike.
Verticillium is found in many US agricultural soils. My particular interest in this olive tree disease is that the southeastern US, with its newly-planted commercial olive trees, may suffer at a greater rate than the rest of the US. Verticillium infests soils that previously grew cotton and when “Cotton Was King” most farmland in the southeast grew King Cotton at one time or another.
The bad news is there is no reliable control method for this fungus. Fungicides are very expensive and hazardous. The best thing to do, if you suspect your olive tree has been infected, is to uproot and destroy.
My next comment is directed toward new olive tree growers in areas where the available agricultural specialists are not familiar with growing and caring for olive trees. When it comes to pests and diseases, unless you are qualified and knowledgeable enough to do so, please don’t make an assessment on your own. Hire a professional who knows and understands olive pests and diseases. Olive trees (Olea europaea) are too important a crop to risk losing your investment and harming someone else’s.
May the sun shine through your branches.