|Wet, humid weather not suitable for the trees|
The deaths of Leyland cypress trees all around Franklin County have been blamed on several diseases, such as root rot and Seiridium canker, which causes bright reddish brown twigs and branches.
Monday, June 23, 2014
By STACEY HAIRSTON - Staff Writer
The Franklin County Cooperative Extension has received an abundance of calls from concerned homeowners regarding the deaths of Leyland cypress trees on their properties.
"We started seeing these cases in April," said Extension Agent Sean Duff. "We have received 82 calls so far this spring, most of them in the past two to three weeks."
Leyland cypress trees are evergreens whose height and ability to fill out are appealing to homeowners for use as barriers around their properties.
"While these are great reasons to want Leyland cypress trees, our area is not very suitable for them," said Duff. "We live in a very humid area and have been experiencing extreme weather conditions, from extreme cold to extreme heat, and these trees do not fair well under those conditions. Last spring was excessively wet and we are seeing the aftermath of that right now."
Root disease is the main cause of the deaths of the trees, Duff said, with 90 percent of the locally-reported dead trees suffering from root disease.
Phytophthora root rot is typically more damaging in situations where soil drainage is very poor.
Duff suggests limiting the amount of water applied to Leyland cypress trees in Franklin County.
"Our type of clay doesn't drain well," he said. "The roots will hold water, causing root diseases to develop."
Trees with severe root damage may exhibit a general yellowing of the foliage and some tip dieback.
Chemical control is not recommended for root diseases in landscape trees.
Seiridium canker is another cause of the dying off of local Leyland cypress trees. This disease causes actual canker sores to form on the tree stems and branches. The cankers will appear as sunken, dark brown or purplish patches on the bark, often accompanied by extensive resin flow.
Scattered twigs or branches killed by the fungus turn bright reddish brown.
There is currently no chemical control measure for this disease, but Duff suggests management practices, such as pruning infected branches with sterile pruning shears as soon as symptoms are noted.
Sterilization is important as the fungus can be spread from tree to tree via contaminated pruning tools.
"This measure could prolong the life of the tree," said Duff. "But if over half the tree is starting to look dead, it is time to have the tree removed."
Disease can spread from one Leyland cypress to another, and with a lot of them being planted in rows and in close proximity of each other, neighboring trees could become infected with the disease of the sick tree, Duff added.