Melanine plaque

[treeseer]

Saw lesions on a red maple and suspected Phytophthora. then excavated dead tissue and saw smooth black area underneath the uppermost sign, unlike P. So is this the melanine plaque indicative of Armillaria? How to examine further to get a better idea?

 

The flare is buried 9"+. Prescription is to take off a lot of the old mulch/dirt/roots now, and inoculate soil under dripline with it. more next fall. This is an understory tree so risk is very low. Cavity on opposite side.

 

Constructive feedback welcome.

[Fungus]

smooth black area underneath the uppermost sign, unlike P. So is this the melanine plaque indicative of Armillaria? How to examine further to get a better idea?

 

Without the presence of rhizomorphs, for the procedure to follow, see my earlier reply after 1.

[Tony Croft aka hamadryad]

I would expect to see more thinning of the canopy and die back with a heavy armillaria colonisation at the stage that would be forming plaques, i think you have Phytopthora, but im just hunching and guessing from personal experiences.

 

I would be interested in the outcome of the investigation as my gut say phytopthora.

[Fungus]

Phytopthora ... the outcome of the investigation

 

The investigation being performing an ELISA field test ?

[Tony Croft aka hamadryad]

The investigation being performing an ELISA field test ?

 

to be honest gerrit i know nowt about the test, only having heard of it and VERY recently seeing my first suspected proper phytopthora case so any links to the elisa test would be good!

[Fungus]

links to the elisa test

 

See Phytophthora : ELISA test.

[treeseer]

1. By using a microscope capable of determining whether the hyphae behind the melanine layer belong to an Armillaria species or that the black layer is of another (fungal : mostly ascomycete) origin.

 

Thanks for the reminder--i'll excise and look closely.

 

ELISA test may be useful--it's been familiar here 5+ years--but i will have a close look first. More flat black stuff observed today--not on paying job but in my own woods.

[Fungus]

By using a microscope capable of determining whether the hyphae behind the melanine layer belong to an Armillaria species or that the black layer is of another (fungal : mostly ascomycete) origin.

More flat black stuff observed today--not on paying job but in my own woods.

 

Although the poor quality (and magnification) of the photo's makes it hard to say something sensible, the first and last two photo's could show melanine plaques, in the first photo of either the necrotrophic parasitic Armillaria mellea or A. ostoyae or of the saprotrophic A. lutea (= A. bulbosa) hollowing the tree inside out and in the last two photo's of either A. mellea or A. ostoyae decomposing dead wood outside in after the tree died.

The second and third photo could show melanine plaques, but one of the many black crusts forming ascomycete Sphaeriales, such as Diatrype stigma, seems to be more likely.

Anyhow, in all cases : microscope.

[treeseer]

Although the poor quality (and magnification) of the photo's makes it hard to say something sensible, the first and last two photo's could show melanine plaques, in the first photo of either the necrotrophic parasitic Armillaria mellea or A. ostoyae or of the saprotrophic A. lutea (= A. bulbosa) hollowing the tree inside out and in the last two photo's of either A. mellea or A. ostoyae decomposing dead wood outside in after the tree died.

The second and third photo could show melanine plaques, but one of the many black crusts forming ascomycete Sphaeriales, such as Diatrype stigma, seems to be more likely.

Anyhow, in all cases : microscope.

 

Thanks!