Black disease spots releasing spores?

[floridaPalmMan]

I bought this phoenix canarysis at a large discount because it was diseased with leaf spot but I figured I'd fight it off and have a healthy tree in a year or so.

Its been sprayed with copper fungicide but today I noticed little raised black bumps with white "fluffy" growths coming from the spots and I have no idea what they are.

Anyone know what I'm dealing with here?

[zero]

4 hours ago, floridaPalmMan said:

I bought this phoenix canarysis at a large discount because it was diseased with leaf spot but I figured I'd fight it off and have a healthy tree in a year or so.

Its been sprayed with copper fungicide but today I noticed little raised black bumps with white "fluffy" growths coming from the spots and I have no idea what they are.

Anyone know what I'm dealing with here?

It's called graphiola leaf spot.  It's all from the same fungus that originates in humid areas.  Once the "fluffy" growth appears it has reached maturity and begins to release spores that remain dormant for a year or so.  Typically it just affects the lowest fronds on Phoenix palms.  It's not fatal but mostly cosmetic and looks horrible when viewed up close.  I had this on Phoenix theophrasti and dactylifera which were both infected from a canariensis on the opposite side of my house.  I've read where it might be controlled with Banrot but I had no luck treating it with a fungicide.  P. roebelenii and rupicola (softer leaves) seem to be immune to it but sylvestris can get it also.

[floridaPalmMan]

@Fusca So would you recommend just chopping off the infected fronds instead of trying to fight it with copper fungicide?

I've got banrot and can try to treat it with that.

[zero]

7 minutes ago, floridaPalmMan said:

@Fusca So would you recommend just chopping off the infected fronds instead of trying to fight it with copper fungicide?

I've got banrot and can try to treat it with that.

I wouldn't waste fungicide trying to fight it.  How many fronds are affected?  Even if you're careful trimming fronds you're almost certain to have the issue come back next year unless the Banrot treatment works.  Your CIDP doesn't have too many fronds now so I wouldn't trim off more than 2 or 3.

[Merlyn]

Copper can be phytotoxic if used too often or with too much concentration.  So I generally don't use it.  I did treat my somewhat smaller Canary with Banrot, and the leaf spot stopped growing on new fronds.  After a couple of years without treatment the spot has come back on the lower fronds.  It does appear to be mostly cosmetic.  A systemic fungicide is probably the only thing that would work, just because of how many dots there are.  I wonder if Aliette or aluminum tris would work?

[andrebazhen]

@Fusca does it look similar? My Ravenala has tiny white spots near to these dry areas 

[Merlyn]

In the other thread I linked the UFL page: https://edis.ifas.ufl.edu/publication/PP140

They say that copper and thiophanate-methyl are the only two things proven to work on it.  Banrot has thiophanate-methyl, which is probably why it worked on my Canary for a couple of years.  Clearys 3336F or Southern Ag Thiomyl are much cheaper.

[zero]

21 hours ago, floridaPalmMan said:

@Fusca So would you recommend just chopping off the infected fronds instead of trying to fight it with copper fungicide?

Actually, in your case it looks like your palm has both graphiola leaf spot and Stigmina palmivora (dark brown spots).  Check out the link @Merlyn posted.  I would continue use of the fungicide you have to battle the Stigmina palmivora which is more serious.  It won't help with the graphiola but it's more important to get rid of the other type of leaf spot.

@andrebazhen, I don't think it's the same thing.  Is it very humid where you are?  As far as I know graphiola only affects palms.  I'm not aware of any non-palms that get infected.