Have you noticed Blue Spruce trees declining or losing more needles this year than usual? The main culprit of excess needle loss is more than likely due to Needle Cast. Needle Cast is a fungal disease that attacks the needles on a spruce tree and causes the tree to defoliate. The biggest problem with this disease is that it attacks the tree in the spring, but symptoms often times do not show up until later in the year or even the following year.
Healthy spruce trees typically will retain 4 to 5 years of needle growth. Those infected with Needle Cast may have only one year of needles. Foliage on inner branches and on the lower portion of the tree are more prone to infection since these areas tend to remain wet for longer periods. When the infection is severe, this disease will kill lower branches and infection can progress to the upper branches.
Once a tree is diagnosed with Needle Cast, the management tactics aim to reduce the spread of disease to healthy tissue. Once needles are infected the cannot be healed or cured and will eventually fall off the tree. Protecting new needles from the fungal pathogen is the best way to fight the disease. With patience, new needles can eventually help to fill in the bare patches caused by the disease.
Keep a close eye on existing spruce trees. The sooner the symptoms are noticed the sooner action can be taken to prevent the disease from getting out of control. Special fungicide sprays can be applied to protect unaffected needles or help prevent new needles from being affected. Fertilization can help provide the tree with needed nutrients especially if the tree has lost an abundance of needles.
For more information or if you have any concerns, contact Ahlum & Arbor today to talk to an Arborist.