Is A Fungus
The Rhizosphaera fungus attacks spruce trees in Missouri. The disease is encouraged by poor air circulation and high humidity. This disease does not usually kill trees, but they may become largely defoliated and unsightly.
What Trees & Shrubs Are Affected By Rhizosphaera?
Spruce trees, mainly Colorado blue spruce and white spruce, are affected by Rhizosphaera. If you do not know what types of trees you have on your property, call the ISA-certified arborists at Hansen’s to schedule a tree assessment consultation.
What Is The Lifecycle Of Rhizosphaera?
The needles of infected spruces change to a purple color between August and November. Eventually, the needles will brown up before being cast off the tree. In most cases, the fungus will show up on one year and older needles in mid to late summer. It is common to see an infected spruce tree with only the current year’s growth on the branch tips.
What Are The Symptoms Of Rhizosphaera?
A good sign of a spruce tree suffering from Rhizosphaera is the presence of black stomata on the needles, viewed under a hand lens. Spider mites may also be apparent on Rhizosphaera infected spruce trees, but this is a different problem. Spider mites do not cause purpling of needles.
What Are The Treatments For Rhizosphaera?
Trees suffering from other environmental stresses, such as drought, poor drainage, trunk wounds, etc. are more likely to develop Rhizosphaera. It is recommended to maintain the health and vigor of trees to avoid fungal infestation. If Rhizosphaera is identified early, pruning off and disposing of the infected branches may solve the problem.
Careful sanitation of contaminated needles is essential to limit the spread of fungal spores to uninfected portions of the tree. After pruning, sheers should be cleaned with denatured alcohol before use on healthy trees. Because spores are spread through water, avoid pruning when foliage is wet. A chemical fungicide may be sprayed by tree care specialists in spring when needles are half elongated (early May) and again when fully elongated (early June).