Spruce needle cast?

DeeGore

New Member
Needle cast is my guess. Older needles are falling off. I don't know how long it's been going on.
 

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KTSmith

Well-Known Member
If it was important to diagnose accurately, one would like to know the pattern of distribution of the browning in the crown (top to bottom? bottom to top? outside to inside?) and on the individual branch (older needles first?). A close look with a magnifying glass: are there itty-bitty black dots? Are they in single or double file? Are they on the upper or lower needle surface? On needles that are part green and part brown, any color gradations between the live and the dead parts? Yellow, purple, orange?
I realize that odds are, calling it "needle cast" and leaving it at that would be fine. Some readers here want to know more than a label for a condition and want to know "what should I look for ?" using available tools.
 

owScott

Well-Known Member
Location
Lafayette
If it was important to diagnose accurately, one would like to know the pattern of distribution of the browning in the crown (top to bottom? bottom to top? outside to inside?) and on the individual branch (older needles first?). A close look with a magnifying glass: are there itty-bitty black dots? Are they in single or double file? Are they on the upper or lower needle surface? On needles that are part green and part brown, any color gradations between the live and the dead parts? Yellow, purple, orange?
I realize that odds are, calling it "needle cast" and leaving it at that would be fine. Some readers here want to know more than a label for a condition and want to know "what should I look for ?" using available tools.
Is needle cast a general term for several kinds of different fungus issues?
 

KTSmith

Well-Known Member
My initial reply to the OP was frustrated by being provided no meaningful information upon which to base an opinion for any causal agent. Yes, those sure look like necrotic conifer needles. Especially without knowing tree species or physical location, I don't have much reason to reckon that fungi are responsible. Sure, they probably are responsible...but which and why?
"Needlecast disease" is a specific term for a particular pattern of leaf injury and associated tree effects caused by a group of distinct, yet related fungi (Ascomycetes). And there are a number of needlecast diseases based on the particular tree/fungus combination. Some fungicides are labelled for specific needlecast diseases, so one size does not fit all biologically or legally. There are other fungi frequently found infecting needles, both the brown and the green parts. Some cause shedding, but are not "needlecast fungi".
However, I do hear the term used to refer to anything that causes needles to fall off the branchlets. In these parts, I've heard the term "needlecast" used in all seriousness to refer to the seasonal mass shedding of old white pine needles.
 

JD3000

Most well-known member
Location
Columbus
To follow that up, I would need a strong hand lens and samples in my hand to really help. Putting them in a ziploc with a damp paper towel may promote some fungal growth to help but this trick doesn't always work
 
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DeeGore

New Member
20201118_134341.jpg
Thanks for the help. The browning is mostly at the bottom, from the inside out. Older needles are falling off. There are black dots when I look at them thru the magnifying glass. The black dots are kind of random, but sometimes in pairs. They are on both sides of the needles. The healthy looking needles have bright white dots in pairs. I would describe the needles as green to light brown to dark brown. I'm wondering if anything can be done to stop it from getting worse.
 

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JD3000

Most well-known member
Location
Columbus
Black fruiting bodies on green needles is usually Stigmina needlecast rather than Rhizosphaera if I recall correctly.
 

Reach

Well-Known Member
Location
Atglen, PA
Slight derail, but related: Besides the obvious silk on the needles, how can you tell if it’s mite damage or a needlecast/similar disease? Diseases and fungi are one big area where my knowledge is very limited.

We have a lot of declining and just plain dead Spruce around here, and we have had Spruce Spider Mite problems the last couple Springs, but I am sure that’s not the only cause of the demise of all these trees.
 

JD3000

Most well-known member
Location
Columbus
Slight derail, but related: Besides the obvious silk on the needles, how can you tell if it’s mite damage or a needlecast/similar disease? Diseases and fungi are one big area where my knowledge is very limited.

We have a lot of declining and just plain dead Spruce around here, and we have had Spruce Spider Mite problems the last couple Springs, but I am sure that’s not the only cause of the demise of all these trees.
I could send you some PPTs on pests and diseases if you would like.
PM for email info
 

KTSmith

Well-Known Member
Ah, much better with respect to DeeGore images. Yes, needlecast fungi are present!
First thing: those white dots are the stomates (or stomata for those who prefer). Those are the breathing pores that allow for gas exchange in photosynthesis (and I think for respiration as well). The needlecast fungi generally fruit on or through the stomata, so that is why the black dots are pretty orderly.
I don't think I saw which spruce species was sampled and where it's located, and that could affect diagnosis of causal agent. At least for blue spruce, Rhizosphaeria will fruit on dead parts of needles. As the provided sample images show black dots on green needles, that shifts the call to Stigmina. JD, does that hold true for other spruce species?
I'd check the extension education materials for your state or nearby state on needlecasts for available control methods.
 

JD3000

Most well-known member
Location
Columbus
Ah, much better with respect to DeeGore images. Yes, needlecast fungi are present!
First thing: those white dots are the stomates (or stomata for those who prefer). Those are the breathing pores that allow for gas exchange in photosynthesis (and I think for respiration as well). The needlecast fungi generally fruit on or through the stomata, so that is why the black dots are pretty orderly.
I don't think I saw which spruce species was sampled and where it's located, and that could affect diagnosis of causal agent. At least for blue spruce, Rhizosphaeria will fruit on dead parts of needles. As the provided sample images show black dots on green needles, that shifts the call to Stigmina. JD, does that hold true for other spruce species?
I'd check the extension education materials for your state or nearby state on needlecasts for available control methods.
I believe it does hold true but differences of symptoms between spruce species is for sure a reality. Rhizo on a blue spruce is pretty different in appearance than how it looks on say a Norway spruce.
 
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