Dying Palms

[AlexV]

Had a thriving triple palm cluster until 2-1/2 years ago when the first one died off (while we were away) by having all fronds turn brown and the whole crown wither and fall off.  Uprooted it and the other 2 continued to thrive until recently, when a second one died in the same manner (see uploaded photos).  No external sign of any infestation, disease, and regular watering and feeding.  Any hints of cause?  Last surviving one appears to be thriving, but...

[greysrigging]

Looks like the dreaded Ganoderma wilt ? 

[Stevetoad]

Could be pink rot. Also how’s your gopher situation 

[AlexV]

Thanks to greysrigging and Stevetoad for suggestions.  Unfortunately, I see no signs of either disease; no stem or trunk bleeding, no pink spores/dust, etc..  And there is no evidence of any subterranean activity (Gophers, ground squirrels, etc.).  I had already considered pink rot, but lowest (dead) fronds appear relatively clean (see photo) although there is a spot with a little greyish/white residue on the inside; and weather has been anything but cold and wet in Southern Californian over the last 6 months (0.01" of recorded rain since May and relatively hot).  I am also attaching a photo of the inside of the broken-off, fallen crown for possible indications.  It appears black and rotted to me  but the perimeter of the broken surface does exhibit some greyish/white residue as well.  I am no palm expert by any means, so any help to prevent the same fate to my last remaining (thriving) palm would be appreciated.  Thanks.

[Stevetoad]

Weird. Doesn’t look like pink rot. How are you watering? Is it possible it’s not getting water? 

[AlexV]

Thanks for reinforcing that it probably isn't pink rot.  It definitely has me stumped.  There is a sprinkler head in the right pittosporum bush that waters the base of the palm cluster fairly uniformly.

[AlexV]

Stevetoad, you were right...it is pink rot!!!  I have not yet removed the dead trunk.  As it dried out, the outer bark layer in the bottom cracked open and exposed previously hidden pink rot!!!  strange, but definitely pink rot.

I will post a pic tomorrow.  It is too dark now to photograph adequately.  I did apply a topical fungicide (Bonide Mancozeb) on it as well as the adjacent (healthy?) trunk and will be treating with a systemic fungicide (Bonide's Infuse) next week.  May not be ideal, but hopefully will be sufficient to save the remaining one.

Any other suggestions on treatment and removal to avoid/minimize cross-contamination?  Thanks again!

[Jim in Los Altos]

3 hours ago, AlexV said:

Stevetoad, you were right...it is pink rot!!!  I have not yet removed the dead trunk.  As it dried out, the outer bark layer in the bottom cracked open and exposed previously hidden pink rot!!!  strange, but definitely pink rot.

I will post a pic tomorrow.  It is too dark now to photograph adequately.  I did apply a topical fungicide (Bonide Mancozeb) on it as well as the adjacent (healthy?) trunk and will be treating with a systemic fungicide (Bonide's Infuse) next week.  May not be ideal, but hopefully will be sufficient to save the remaining one.

Any other suggestions on treatment and removal to avoidr/minimize cross-contamination?  Thanks again!

Sometimes it's not pink rot that kills the palm but it appears afterward feeding on the rotting trunk. I had to cut down two healthy mature King palms because they were about to grow into power lines. They were healthy robust palms. Several days later the pink rot began to appear on the stumps and grew rampantly as the trunks rotted. The cut down trunk quickly developed pink rot as well. Pink rot is common behind old dying leaf boots as well and dries up after  they fall from the trees. 

Edited December 16, 2019 by Jim in Los Altos

[AlexV]

Jim, that makes more sense.  I had jumped to a conclusion.  Thanks for the correction.  So, it appears I still have a mystery on my hands as to the culprit.