Using Science to Enrich Beautiful Landscapes
What you’ll see… are signs of infection beginning to occur in the late summer on both Spruces and Pine trees. The signs are seen as black dots or lesions on the newest of needles. At that time, the fruiting bodies (pycnidia) of the fungus emerge from the stomata or “breathing” pores of infected needles. These may be observed by examining needles with a hand lens. The fruiting bodies resemble tiny black dots in neat, even rows. The second summer after infection, symptoms appear as yellow needles which later turn purplish-brown and drop from the tree. A few of these infected needles may persist on the tree over the winter and drop off the following spring. Needlecast disease will infect all three years of needle growth. When the disease has been left uncontrolled and unmanaged you will see heavy shedding within the first 2 years and then from that point on, the tree will always be thin with only the 1st years growth hanging
on with some of the previous year’s growth. At least half of the previous year’s growth and all of the 3rd year’s growth will be missing because the tree couldn’t maintain diseased needles. In severe cases of infection the needles will also be very Purple.
You should… Keep the ground below clean of all needles so the disease can not continue to rapidly spread. Avoid watering the needles directly and prevent pools of water and excess moisture from gathering around the tree.
We can help by…applying protective fungicides to prevent needles from becoming infected leading to Needlecast disease. It is important to protect the new growth once it begins emerging therefore fungicides should be applied in a timely manner when the new needles begin elongating in the spring and again four-five weeks later to ensure adequate disease control. During the first season of control expect no visible improvement since we will beginning to protect the new growth only and it won’t be until the following season that it remains on the branch. It also highly recommended that a third and final fungicide be applied in the mid to late summer. Finally, when the tree(s) are thin and weak we recommend deep root feeding them with a high quality slow release fertilizer so we can build back on each season’s growth as aggressively as possible.
Posted on: August 4, 2015
What you’ll see…is wilting leaves and dieback of branches, often one at a time or on one side of the tree. This can occur over a number of years, with remiss...