How do you treat a needle cast on a blue spruce?
How do you treat a needle cast on a blue spruce?
Fungicides with the active ingredient chlorothalonil, copper hydroxide or mancozeb will protect new spruce needles from infection by Rhizosphaera.
- Make one application in spring or early summer when the new needles have grown to half their mature length.
- Make a second application 3 to 4 weeks later.
What does Rhizosphaera needle cast look like?
The first noticeable symptom of Rhizosphaera needle cast is a browning and loss of the innermost needles on lower branches of spruce trees. Often, the youngest needles at the tips of branches remain healthy. Rows of small, black spheres form along the length of infected needles and are visible with a 10X hand lens.
What does needle cast look like?
Trees affected by needle cast disease have needles that turn yellowish in summer, gradually changing to purplish brown in late winter and spring. If you look at the needles with a hand lens, you’ll see rows of small black dots. These dots are the fruiting bodies of the fungus, and they are diagnostic of the disease.
How do you get rid of Rhizosphaera needle cast?
Management & Treatment Options
- Prune out severely affected branches.
- Rake up and dispose of fallen needles.
- Begin treatment with a registered fungicide in spring at half-needle elongation.
- Deep root water during periods of drought.
- Fertilize with Arbor Green PRO to invigorate plant growth.
Can needle cast be cured?
Once needles are infected they cannot be healed or cured and will eventually fall off of the tree. While there are fungicides that help to manage this disease, the main use is in protecting new needles from the fungal pathogen.
When do you spray for needle cast?
Begin needlecast treatments in spring when new needles are 1/2–2 inches long. In the Northeast and Northcentral states, start spraying for Lophodermium needlecast in mid-July and early August. Once treatments begin, reapply Daconil® fungicide every three to four weeks until dry weather stabilizes.
Why is my Colorado blue spruce losing its needles?
Needle Cast Disease The Colorado Blue Spruce often loses its rigid needles after wet seasons. The Rhizosphaera fungus, which thrives in the wet conditions, leads to the needle loss as it takes hold of the spruce.
Why do blue spruce needles turn yellow?
Rhizosphaera needle cast is a fungal disease that causes blue spruce needles to turn yellow in the summer, before turning them red to purple in the fall. Infected needles eventually drop off. Rhizosphaera needle cast can eventually kill a blue spruce if untreated.
Will blue spruce regrow needles?
Generally, spruce trees will regrow as long as buds are available, but pine trees pruned past the last set of needles on a branch will not.
What causes needle cast on blue spruce?
Rhizosphaera needle cast is a fungal disease, caused by Rhizosphaera kalkhoffii that attacks the needles of Colorado blue spruce in the spring, as new needles emerge. However, infected needles often don’t show symptoms right away, and may take one to three years to develop.
What causes needle cast on Blue Spruce?
What is the lifespan of a blue spruce?
Growth and Yield- Blue spruce is apparently a long-lived tree, surviving up to 600 years or more. Diameter growth is slow; trees 10 to 13 cm (4 to 5 in) in d.b.h. may be 125 to 135 years old; at 46 to 56 cm (18 to 22 in), they may be 275 to 350 years of age (84).