Advice needed for struggling mule palms

[Palm101]

Hello everyone.   Any input regarding my mule palms would be greatly appreciated.

 

I used to have four mule palms but the one on the left died about a year ago. I had it completely removed and replaced it with an other mule which died just a few months later. I wasn’t sure what was going on and reached out to University of Florida and received some recommendations.  Both times, I had tried to save the palms by spraying them with a systemic antifungal, which I do not remember the name of at the moment.  Unfortunately, it did not seem to help or did not help enough, and I lost both of the palms.
 

I was hoping that just removing the palm wood prevent spread to the other three mule Palms.   Unfortunately, a few days ago I started noticing some discoloration on the leaves of the remaining palms.   The severity of the changes seems to be most noticeable on the left which is just adjacent to the area of the palm that was removed and filled in with grass.  

I kicked off a boot on one of the trees and noticed whitish discoloration. I also noticed that there was significant moisture, bugs, worms, as well as dirt behind the boot.   Hi then began examining other boots and noticed the same changes. I made a decision to remove as many of the boots as I could to prep for further antifungal treatment tomorrow.   It seems as though removing the boots help me remove a lot of the moisture and decay. Not sure if it will prove to be helpful or not in the long run.
 

any recommendations or input would be most appreciated as I really love these palm trees and would hate to lose them. But once they start to go downhill, they seem to go really fast.  
 

unfortunately, I haven’t been able to find any arborist or specialist who can help treat them in Jacksonville Florida

 

Thank you so much

[Merlyn]

@Palm101 welcome to Palmtalk!  The first two diseases that come to mind are:

• Fusarium - typically one-sided death of fronds.  So sometimes half the frond is yellowed and dead...but the other side looks pretty good or still green.  I lost a Queen to this 5 or so years ago.  Mules are susceptible too, though somewhat resistant since they are half Queen (very susceptible) and half Butia (not susceptible).  I don't know if Mules also get the one-sided frond death symptom, and I can't tell from the photos.  It is easy to spread via pruning tools, so clean your loppers between palms with bleach or rubbing alcohol.  There is no known cure and they die very fast once infected.
• Ganoderma - a soil based fungus that kills the lower part of the trunk.  All palms are susceptible, and it can stay in the soil for many years.  A common sign is the fungal conk growing out of the side, but that only happens occasionally and not always.  It is also 100% fatal and incurable.  Ganoderma could explain why the replacement palm died in the same spot as the old one.  But without a lab test or a conk there'ss no way to know for sure.  

IF you have seen the one-sided death or a conk, then it's a positive diagnosis.  Otherwise it's hard to guess.  Severely overpruning them is definitely not going to help their chances of survival.  What have you been doing for watering and fertilizer? 

Here's a good disease overview.

https://ipm.ucanr.edu/pdf/pestnotes/pnpalmdiseases.pdf

[Palm101]

Thank you, Merlyn.   
 

I have been fertilizing them every three or four months with a formulation by Lesco for Palms.  I have to check the formulation tomorrow but think it might be 8-2-12.   
I fertilized them with 5 pounds each of fertilizer according to advice I was given in the past.

I try to avoid having my sprinklers hit them directly. I have some nearby sprinklers that water the lawn twice a week for 45 minutes.

I guess my idea to prune the boots was not a great one. I just didn’t know what to do since I’ve lost two of these pounds in the past and it seems like they now have some white substance attacking them and causing the leaves to die. I don’t think the white substance in the pictures is normal but I could be wrong. It seems like the healthiest plant on the right side did not have any white substance and the boots were much more firmly attached so I did not have to prune them. The other plants seemed like they were taking on a lot of water and dirt as well as bugs and worms and had more of the white substance, more browning of foliage. 

is there somewhere that you know of where I could have the leaves or other portions of the stock tested to see what is going on before it is too late and I lose three more of these palms? 

From first two diseases that you mentioned.  I really hope that’s not what I’m dealing with. As expensive as these trees are, it’s also expensive having them removed…and backyard will never look the same

Thanks so much 

 

Craig 

[Merlyn]

@Palm101 Lesco makes good fertilizer, IMO.  I used the 13-3-13 palm type for a while before HD switched to carrying 8-10-10.  The recommended dose on 8-2-12 is 1.5lb per 100sqft of canopy.  So for a Mule palm that's about 12' diameter, that's 6*6*3.14 = 113sqft.  So you'd use roughly 113/100 * 1.5 = 1.7lb of 8-2-12 per palm, 4x per year.  I'm not sure if a 5lb dose could cause problems or not.  On a recent planting I'd think it could cause root burn.  In a partially grassy area it might not be a big deal, since the grass may absorb some of it too.  Just make sure you are sprinkling the fertilizer evenly under the canopy diameter, and not leaving any significant big piles anywhere.  If the palm fronds started going yellow and brown a week or two after fertilizing, it might be fertilizer burn. 

As far as the boots go, they typically fall off over time.  If there's a hidden trunk fungal rot then taking them off is a good way to find it.  Otherwise usually it's just a cosmetic choice.  The trunk under the boots should be rock hard, even if there's a bit of dirt or fungusy stuff in there.  The only white palm fungus to be concerned about is a Ganoderma conk, which will look like a shelf as the conk matures:

https://www.juniperlandscaping.com/crm/media/public/Ganoderma.pdf

As far as testing goes, UFL / IFAS does testing for a fee.  I have never used the service, but here's a link:

https://plantpath.ifas.ufl.edu/misc/media/PDC/UFPDC-Form-Sample-Submission-Palm.pdf

My comment on overpruning was actually referring to the fronds.  Palms will "eat" the oldest fronds to provide nutrients for new growth.  So cutting them off before they are dry and dessicated actually deprives the palm of nutrients.  It's a good idea to prune if transplanting, since you are also cutting off roots.  So if you have a field dug palm planted in your yard, they usually cut off about half the fronds to balance root loss.  Otherwise leaving them is a better choice.

[Jim in Los Altos]

Why such severe pruning? Green fronds should not be removed as they are productive food producers for the rest of the palm and the palms just look much better with a full canopy. Too much pruning will stress the palms and stunt growth. 

[Palm101]

Because I thought all the fronds that I cut off were starting to have disease. My intention was to clear as much of the potential disease as I could, and then spray them down with an antifungal once someone was able to recommend. I’m not even athat I cut off we’re starting to have disease. My intention was to clear as much of the potential disease as I could and then spray them down with an antifungal once someone was able to recommend. I’m not even 100% sure that they are diseased, but they were starting to look like it to me so I cut many fronds and boots.  I agree, they do not look nearly as good as they did before. But I have lost two in the past and I’m just trying to avoid further problems.  
 

I was starting to get brown spots all over the leaves, which didn’t look like regular aging and was starting to get white pottery substance on the stalks and also inside the boots

 

I wouldn’t have panicked and reacted so quickly except for the fact that this is reminiscent of what happened last year when two of them died within a few weeks after developing similar changes

[TropicsEnjoyer]

Absolutely butchered those palms. That’s issue #1. And two, trimming dying fronds won’t stop disease. If a palm is diseased by the time it manifests it’s not localized, it’s all over. Lastly, palms stressed from lack of fertilizer will not benefit from cutting the half brown half green leaves, because you are only amplifying the issue by literally cutting off nutrient reserves in the fronds.

[Tomas]

Did the leaflets on your palms look like those in pictures posted by me ?