Needlecast is dangerous to spruces and other conifers, affecting their structural integrity and destroying them, killing them after seasons of needle loss.
Fungus, like most tree diseases, will show itself in one of just a few ways.
- Abnormal growth
- Wilting needles
- Discoloration or growth (scabs) in the bark.
- Fungus growing on your tree.
Needlecast Tree Disease -
If you have ever seen a spruce with healthy green needles at the tips of the branches, but no needles further down the branch, welcome to needlecast. This fungus attaches itself to spruce trees, it has a strong preference for Blue Spruce trees and can attack the white spruce and other conifers, like pine and fir, that are also susceptible. The Norway spruce is resistance to the disease.
Needlecast takes time, usually about four seasons, to completely take hold of a tree but once the first signs of the disease begin to show on your tree it will become an obvious eyesore on your property. This fungus hits trees that are already stressed, either from drought, poor nutrients in the soil or too many trees planted together. Needlecast diseases of evergreens are caused by several fungi, but all the needlecast fungi form small structures on the infected needle in which thousands of spores form. These "fruiting structures" may be black, orange-red, or tan, depending upon the fungus.
What to Look for
Signs of needlecast will begin in the fall season and typically starts at the bottom of the tree with the presence of brown or purplish needles. The fullness of your tree will also decrease, especially near the bottom, and your tree even has potential to lose all its needles.
- Discolored needles fall off in late summer to fall.
- Infected trees have few needles near the trunk and look thin ,or see-through.
- Damage typically starts on the lower branches and moves up the tree.
- If most needles are infected for 3 to 4 years in a row, the branch will die.
- Trees affected by needle cast disease have needles that turn yellowish in summer, gradually changing to purplish brown in late winter and spring.
As seen through the lens with a magnifying glass, there will be rows of small black dots. These dots are the fruiting bodies of the fungus, and they are a characteristic of the disease. This disease is spread by rainwater splashing the spores from infected needles to newly emerging needles in the spring. Pycnidia, the fungal fruiting bodies containing spores, begin forming in rows on infected needles during spring when moisture is high.
Action must be taken quickly as soon as the signs are noticed.
Remove dead and dying branches from your tree. Remove the lower branches from your tree. Continue to fertilize the tree’s soil and mulch around the tree to provide moisture and hold in nutrients. Do not pile mulch up against the tree, rather leave two or three inches around the tree for drainage. Make sure sprinklers do not directly hit the needles.
Rhizosphaera needlecast may be controlled in one year if fungicides are applied correctly and at the right time. However, severely infected trees usually require two or more years of fungicide applications. Even though fungicide application will effectively control this disease, reinfection may occur in subsequent years. Having the professionals at Advanced Tree Services come and treat your trees is the first step toward saving them.