Andy has a large group of 20 year old cotton-less cottonwood trees on his property in Humboldt County, NV. Last year he started seeing galls on branches of one row of the trees (rest are fine).  This year more galls and the leaves starting to curl up and die.  The trees have been on the same watering system for 20 years.  He also has a Willow and it is fine.  Some time back he did introduce what were supposed to be beneficial insects but has not done that in a good while.  He is wondering what is wrong with his trees and how to treat them? Attached are pictures (if you require more contact Catherine Bergey at the Humboldt County office).  Please respond directly to Andy at his email address.  Thank you