To Remove or Not Remove Ash Trees with Dead Branches?

Q. I have been following your comments on ash tree decline. You believe those trees should be promptly removed.  Is this to contain the disease?

Does Ash Decline Exist? Something is causing the limbs to die and water and fertilizer dont change anything.

A. This disease is called Ash Tree Decline in Arizona and Ash Dieback in California. In California, ‘Raywood’ ash has been the hardest hit. In Arizona and Nevada ash trees like ‘Modesto’, ‘Raywood’, ‘Fan-Tex’, ‘Rio Grande’ and other ash trees having Arizona ash genetics have shown branch dieback and “failure to thrive” symptoms.

 We suspect it is an MLO and the "disease" is spread by "something" from tree to tree. Insects? Pruners? Cicada feeds on plant roots like this tree, climbs out of the ground onto the trunk and pupates (leaves its "skin" behind, cuts into trees with its ovipositor and lays its eggs. A possible culprit in its spread?

The disease itself is thought to be an MLO (Mycoplasma Like Organism). What we do know is that it’s probably transferred to new trees by insects, just like other MLO’s. So, my recommendation has been to contain the disease by removing potentially infected trees, so they don’t become a source of inoculum to other trees. If suspected trees receive more water and fertilizer but fail to grow, then we should assume it has Ash Decline until we know differently. I have not seen it on any other trees but relatives of Arizona ash.