Mule Palm Fungus - one dead, more to protect - Lower Louisiana (just outside New Orleans)

[TBell]

How do you find out the fungus that killed your palm, so you know what to use to treat the others with? Just lost a Mule this week; having it removed - stump and root ball and all.  But I want to treat 5 other Mules in the area, and 2 Queens.  Read a previous thread about a Sylvester Palm Fungus (and some additional remarks over 2 years) - suggesting many things for the person who posted and what fungicides they already had on hand. I'm looking for a heart / crown treatment and a soil drench.  Are there fungicides that do both? Looking to buy something asap and get my remaining palms treated. Any suggestions to help me treat my other palms would be great, thanks! 

[PalmatierMeg]

Do you have photos of the dead palm before its crown fell off? The bare trunk tells me nothing - I need to see the progression of the disease in the fronds. When did you first notice symptoms? What were those symptoms? Are other palms showing symptoms? How quickly did the palm go from healthy to dead?

Back in 2015/16 I lost all of my queen palms, both mules and a Washy to fusarium wilt a disease carried by an insect vector and infected gardening tools. Early on the most significant symptom is that fronds start dying, turning yellow then brown on one side of each frond, then the other. Also, dead fronds turn a peculiar grayish-brown color. From the time you notice the die back the palm will be stone cold dead in 2-3 weeks. The disease is invariably fatal and there are no treatments. Nor do I know of any pre-emptive actions you can take to forestall future infection.  As I found out over 18 months, once my first queen died all the others looked healthy but were already doomed. They fell like dominoes, one or two every month or so.

You have to have the whole palm removed and sent out with your garbage, then preferably incinerated. Disinfect tools that came into contact with the dying palm. Replant with palm species resistant to wilt. No queen, mule or Washy will ever grace my yard again.

I'm not telling you the palm died from wilt - you haven't given me evidence one way or another. Maybe your palm is a one-off and had other problems. But if you see telltale symptoms in some of your mules or queens that's an ominous sign.

I found one photo of a frond from one of my dying queens that shows one side healthy green, the other a yellow-brown pall of death.

 The link below posted by PTer @Rd003 in 2018 shows his experience with wilt. My own photo of a diseased frond is included in the topic

https://www.palmtalk.org/forum/topic/56271-fusarium-wilt-is-killing-everything/

 

[Merlyn]

As Meg asked, do you have any photos of the dying Mule, prior to it losing it's head?  There are a variety of fungi and bacteria that attack palms, some fungicides work on some diseases but not others.

• Fusarium - kills Queens, Washies, and Mules.  Typically one side of each frond dies, while the other side looks mostly "normal."  Considered incurable, but Banrot *might* be a pre-infection treatment for other palms.  It *might* have worked in my yard, where I lost one Queen on the SE corner of the house, dosed the other 8 Queens and 1 Mule, and none of them caught it.
• Thielaviopsis - a trunk rot that affects all palms, generally affects the upper half.  Also no known cure, though Banrot is claimed to be effective.  A common symptom is a "bleeding trunk" with weeping liquid coming out.
• Ganoderma - a trunk rot that affects all palms, generally the lower half near the base.  Usually shows a shelf-shaped mushroom "conk" near the base of the trunk, but not always.  No known cure.  Not easy to diagnose unless you see the conk.
• Phytophthora bud infection - a but rot that affects all palms.  Relatively easy to cure if noticed early, typically hydrogen peroxide, Daconil, and Mancozeb are good treatments.  Symptoms are no new fronds, or distorted or mushy new spear. 

If you have photos from a few weeks or months ago, that would help a lot.  Just based on it losing it's head I might guess Thielaviopsis.  Also post pictures of your other palms.  If it's something like Fusarium then you can usually see it with the one-sided-frond-death.  The Mule next to the dead one looks relatively normal, if a bit overtrimmed.  One thing to keep in mind is that diseases are really easy to spread via your pruning tools.  So if you use a lopper, make sure to disinfect with rubbing alcohol or a bleach solution between palms.  If you clip off a frond from a diseased palm, then clip off a frond on another palm, there's a reasonable chance of spreading whatever it is.  Chainsaws are the worst tools, because it's nearly impossible to actually clean them. 

[TBell]

I found a picture from when it started leaning - early November. I propped it up w a wooden pole (tied to it with burlap) as I was told it could make a come back. Was green, but just listing w a loose crown. Always stayed green, but new fronds were light green and then stopped shooting up. Never really turned yellow. Then it leaned more and more. I untied it this week, and grabbed the top and it came off easily (and went right to the dump). The trunk and ball will be removed by a professional tomorrow. I just started cleaning my pruners and saws-all blade after pruning each palm due to this occurrence. All the other palms seem healthy and green (yes, the one next to it did get over pruned), but there are 4 more 50’ away that look good. I fertilize 3 times a year (spring, summer, fall) with Carl Pool 12-4-12 fertilizer. Started that 3 years ago. They are all 4 years planted (came to me 5’ tall in 100gal pots) the picture with the silver airstream is from late December. The others from early November. 

[TBell]

The palms next to the dead one. The Mule right next does seem to have some brown fronds, but it has a healthy new shoot coming out top, and healthy seed pods growing too. We had a freeze this winter - 28 degrees for a couple nights. 

[TBell]

All other palms 50' away by the pool look fine. 

[Merlyn]

Great pictures, I love the pool setup!  So the photos rule out Fusarium, because the fronds didn't have the one-sided death, and essentially stayed green until the top fell off.  There's no sign of a bud rot like Phytophthora.  Ganoderma usually doesn't kill palms that way either, but the palm only has a couple of feet of trunk.  Ganoderma attacks usually the lower 3-5 feet, so it's possible.  My best guess is Thielaviopsis fungus.  It degrades the fibers towards the upper side of the trunk, and is frequently the cause of "sudden crown drop."  Here's a couple of fact sheets on my guess, these are from UFL's palm info pages:

https://edis.ifas.ufl.edu/publication/PP143

https://idtools.org/palm_symptoms/index.cfm?packageID=1111&entityID=3350

and from an IPS director:

http://www.marriedtoplants.com/palms/fungus-among-us-thielaviopsis-paradoxa/

Here's similar Ganoderma fact sheets:

https://edis.ifas.ufl.edu/publication/PP100

https://idtools.org/palm_symptoms/index.cfm?packageID=1111&entityID=3320

The downside of both of these diseases is that they are considered incurable.  Thiophanate Methyl is rated to work on some varieties of Thielaviopsis fungus, and is used in nurseries for various root rots.  It's not specifically claimed to work on Thielaviopsis Paradoxa, which is the variety that attacks palm trunks.  But it *might* help prevent the spread to other palms...maybe.  Cleary's 3336F, Banrot, Southern Ag Thiomyl, Bonide Infuse, and others use this. 

Most fungi get into palms through open wounds in fresh tissue.  To avoid this (as much as possible):

• Only cut off fronds that are dried out, dead and dessicated.  Cosmetically this isn't ideal, and can be a problem for walking clearance around something like a pool.  I chop off fronds early along my pathway, otherwise I wouldn't be able to walk down it!
• Sanitize your loppers between each palm, using a bleach or rubbing alcohol solution.  Avoid chainsaws or loppers with serrated teeth, as they are tough to impossible to actually sanitize.

For your dead palm, I'd recommend digging it out as one piece.  If they come in with a chainsaw and stump grinder they're just flinging fungi-infested bits all over the yard.  It's not that difficult to dig out a palm that size, because the roots are thin diameter and fairly easy to cut.  I've done it with a sharp shovel and a reciprocating saw with a 12" 3TPI carbide toothed blade.  Just slice in around 6" away from the trunk and you'll be into thin roots.  One that size would take me ~30 minutes to dig out...in my soft Florida sand.  If they've already come and ground the stump, make sure you bag up and get rid of all the grindings. 

[TBell]

Thank you for all the information!!

They removed the palm yesterday (unfortunately they didn't take pictures), and to note, there was a sufficient amount of water in the hole when removed. My neighbors been having a drainage / downspout problem, that becomes my problem in that area, combined with my driveway run off as well.  When I planted them, I dug down 2 feet and filled the bottom of the holes with pea gravel and sand to try and "raise" them some and give them drainage. Unfortunately, I think they just sit in to much water saturated soil as that is the "low spot" between our houses.  At least the area by the pool does not have the same problem.  I do make the mistake of cutting a bit more than I should on the fronds. My wife likes the trunks "cleaner" looking, and I should probably hold off cutting them so tight (after reading your post and the related articles about how the fungus can attack the plant). Yes, sometimes I have to cut them as you do, just to be able to walk around the pool!

I've seen posts about a "drench" and a "trunk / frond spray". Was looking at Banrot for a drench; can that be applied as a trunk spray too? Amazon has the Southern Ag Thiomyl that instructs to use as a spray. Would combining a Banrot drench and Southern Ag trunk / frond spray be advisable? For the cost of the palms and removal, I'll gladly spend a few bucks to give them anything that might help keep them healthy. I was told to find something with copper as well (not sure if that affects OTHER fungus in the area or what). There was a recent occurrence of lethal bronzing on some neighbors Queens three houses down; but I was told it doesn't affect Mules (but I am worried about my 2 Queen Palms). Trying to look into an prescription injection that you put in the trunk...(??)

 

Yes, thank you, the back yard has been a labor of love (bought in late 2015 and started renovating in 2019). The area I lost my palm had 6 stumps from Queens that had died with the previous owner (age or freeze - they were 30' tall per the neighbors)  So we started renovating the back yard (pool refurbish and travertine pool deck installed where the previous deck was missing, Lol)

I bought 6 Mules and 2 Queen palms from a movie I worked on for a VERY good price, but had to buy a few beers for my buddies to help me plant them (the travertine deck had been laid down before the Palm bargain landed in my lap). 3 broken wheel carts and a borrowed landscape dolly and a few cases of beer later...   We live just outside New Orleans, and love our backyard! 

[Allen]

1 hour ago, TBell said:

Thank you for all the information!!

They removed the palm yesterday (unfortunately they didn't take pictures), and to note, there was a sufficient amount of water in the hole when removed. My neighbors been having a drainage / downspout problem, that becomes my problem in that area, combined with my driveway run off as well.  When I planted them, I dug down 2 feet and filled the bottom of the holes with pea gravel and sand to try and "raise" them some and give them drainage. Unfortunately, I think they just sit in to much water saturated soil as that is the "low spot" between our houses. 

 

I wouldn't do that you are creating a bathtub effect and holding more water in the hole. 

[TBell]

Already did, 4 years ago. Lots of clay and black soil here - I removed a good bit of the clay and added sand a gravel as I was told it drains better, and the palms don't mind the sand.  That area unfortunately doesn't dry out; is an area where water collects as it's heading towards the street. May be an area that just isn't good for palms (unless I do an elevated bed in the future).

[Merlyn]

So I'd revise my comments somewhat...  With the root initiation zone sitting in water it's harder to guess.  Long term overwatering is usually drooping fronts losing color and turning yellowish.  I have no idea what "death by water" actually looks like, or if that's to blame here.  If the palm suddenly couldn't pick up water, it might suddenly droop over.  A while back I bought a Dioon Spinulosum from a fellow PT-er, he had to rip it out of the ground where it had rooted in for 5+ years.  All the fronds immediately fell over, literally overnight.  That's a classic case of "lack of hydrostatic pressure."  Could this happen to a palm in the ground if the RIZ suddenly got swamped?  I'd guess the main roots are waaaay down into the soil.  But if the upper roots or RIZ got swamped would it rapidly cut off water flow into the palm?  Maybe...  Did you see any sign of brown or mushy roots when they removed it?  Healthy roots are white and fairly tough.  A lot of brown mush roots could be a root fungus caused by sitting in water.

As far as fungicides go, it's hard to judge because we really don't know why it died.  Banrot is a combo good against root rot, so a soil drench might be useful.  Foliar sprays are good if the roots can't pull up the fungicide systemically.  It's really guesswork, you might throw $20 in fungicides at it, and not fix anything.  Or you might throw $20 in fungicides and prevent a root infection in the neighboring palms.  Personally I'd avoid copper sprays in this case, they are good for surface stuff but that doesn't seem to be your problem.  Copper can also be phytotoxic if mixed too strong, or applied too often.

[TBell]

I spoke with the the landscaper who removed the palm; he said the roots were solid and firm, just very wet. Said he dug the hole about 3 feet down to be sure and get all the roots, it was sloshy and wet, and water collected in the hole about a foot when he had the palm root ball out.  There were 6 Queen palms in the area for years before I bought the house, but they were in a raised bed of ground so to speak (6-8" of ground elevated above the driveway, edged with tiles); just stumps when I got the house. I had the driveway re-poured as it was well broken up, and re-leveled everything to have water flow away from the house and garage and towards the street. Ultimately, I'm learning that area is wetter than usual due to my changes with the drive and my neighbors drainage issues. Curious that it took 4 years for the palm to react (looked GREAT from the moment I planted it!). I'll hit it's area and the neighboring palms with a fungicide drench and hope for the best - worth the preventative measures. Thanks for all the input and knowledge! Enjoy the beginning of Spring!

[Merlyn]

@TBell I guess if the water drainage problem is relatively new, then you could blame it on that.  If it's been sitting in a water table only about 2 feet below the surface for years....harder to guess. 

I did have one random thought this afternoon as I was driving past a row of Livistona Saribus.  Every time I go down that road, it seems like the center islands are missing another palm head.  The symptoms are very similar to yours, it occurred to me that it might just be overtrimming.  The landscapers on these Saribus come through several times a year and cut off half the crown on each palm.  This makes them all "pencil point," to where there's only a 6" diameter top to the palms...instead of nearly 2 feet diameter on a healthy Saribus.  At that point there's not a lot of older frond bases to give structure to the trunk.  A good storm could simply snap the bud off or damage it enough that the palm can't grown new leaves.  Old leaves will hang on for a long time, even if the vascular system is damaged and can't feed them.  3 or 4 months seems like a long time, but if you had a big storm back in October-November it might have damaged something inside the trunk.  

That's all speculation, though.  Did the landscaper say if the trunk was weak or rotten in the middle?

[TBell]

Hmmmm…. Hard to remember if we got a hard storm - the hurricanes start to blend together, Lol.

He didn’t say anything about the trunk, but when I “ripped” the head off myself, I grabbed the remaining trunk at the top and pulled on it to see if it would just pop out of the ground or fold over. It was fairly firm, but it did ooze some brown water / juice out of the trunk near the bottom 2’ feet as that was the leverage point being squeezed.