Rhizosphaera needle cast is caused by
the fungus Rhizosphaera kalkhoffii
. The fungus survives winter on living and recently killed needles. In spring through early autumn, spores spread to new needles within the tree or in neighboring trees via splashing water.
How do you get rid of Rhizosphaera needle cast?
Consider
treating affected trees with fungicides containing copper as the active ingredient
(e.g., Bordeaux mixture) or chlorothalonil. Treatments will not cure existing infections, but can prevent additional infections. Apply treatments every three to four weeks starting as new needles emerge in the spring.
What trees get needle cast?
Stigmina and Rhizosphaera Needle Cast in Trees
White spruce and other conifers, like pine and fir
, are also susceptible. The first step is to get a reliable diagnosis. Experts recommend that you send a few diseased needles to a diagnostic laboratory where they can run tests to identify the problem.
What is spruce needle cast?
Needle cast is
caused by a related group of fungi (Ascomycetes)
, which cause more damage to coniferous foliage in North America than any other group of fungi. Severe infection can result in significant growth reduction in seedlings.
When should 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.
How do you treat Dothistroma needle blight?
Dothistroma needle blight can be controlled, but not cured, with
sprays of fungicide
. As with any needle blight disease, the aim of spraying the tree is to break the annual cycle of infection in the new needles. Multiple seasons of treatment are needed before results are noticeable in the tree.
Does Norway spruce get needle cast?
Rhizosphaera needle cast disease is caused by the fungus Rhizosphaera kalkhoffii Bubak. Colorado and Engelmann spruce are very susceptible, but
Norway and white spruce are somewhat resistant
.
What causes needle drop?
Browning or wilting foliage (and subsequent foliage or needle drop) on both deciduous and evergreen tree species can be caused by
excessive heat, drought, and water stress
. You may find this stress-caused damage throughout the tree but it’s usually found at branch tips.
What fungicides contain chlorothalonil?
Chlorothalonil-containing products are sold under the names
Bravo, Echo, and Daconil
. It was first registered for use in the US in 1966.
What causes spruce needle rust?
Spruce needle rust is caused by
fungi from several species of the genus Chrysomyxa
. These rust fungi live half of their life cycle on spruce needles and the other half on an alternate host in the Ericaceae family.
What does Rhizosphaera needle cast look like?
How to identify Rhizosphaera needle cast. In spring or early summer,
new needles at the branch tips are green
, and the older needles turn brown to purple. Use a magnifying glass to look closely at both green and discolored needles. Tiny black bumps can be seen arranged in neat rows on infected needles.
What is the most disease resistant spruce tree?
Norway spruce (P. abies)
is highly resistant to this disease. Some Colorado blue spruce cultivars, like ‘Hoopsii,’ and ‘Fat Albert’ are reportedly more resistant to the disease.
Why do blue spruce needles fall?
Spruce and pine trees can be
prone to several fungal infections
that can lead to needle discoloration and early drop. One of these fungal infections is known as cytospora canker, which primarily affects Colorado blue spruces.
Can needle cast be treated?
Needle cast disease is treatable
. Within a few years after treatment, an infested spruce tree can start to produce healthy new needle growth again. Left untreated, a severe case of needle cast can lead to continual thinning and decline of the tree.
What is the best fungicide for evergreens?
We use
propiconazole or thiophanate methyl
or a combination of the two. Fungicide injections using propiconazole can also give good control. Infected needles and leaves are the main source for re-infection of the new plant foliage.
When do you spray evergreens for fungus?
If your tree or shrub had a serious fungus problem last season, you may be considering applying a fungicide to deter the disease this year.
