I have a few leyland cypress that were planted as privacy trees on the edge of the lot lines of my house. They have grown very well & are about 25 feet tall, perhaps 10 to 12 years old. Last year, we had a prolonged regional drought, and many leyland cypresses in the general area started to brown out and then die.
I thought at the time it was drought damage. But I was told recently that there is also a parasitic infection attacking the trees that manifests by individual branches going brown and then the whole tree dieing.
Q: Is that true, and if so; can the parasites be treated against - how and what is the probability of success.