Nightmare sooty mold

[quaman58]

Hey all, the past couple years I’ve had some terrible outbreaks of sooty mold, but this year is the worst. My understanding of it is that ants farm scale and mealy bug for the honeydew that they produce. I have always assumed that the excess honeydew then falls to the ground, unless something like a leaf intercepts it. Then you have a perfect syrupy medium for the mold to grow. So the theory is, control the ants and you control the sooty mold. Somebody can feel free to correct me if I’m wrong. Do I see ants and scale insects? Yes. There is it appear to be a big enough problem to create the secondary issue? Not that I can see. Regardless, I’ve spent the entire spring and summer cutting off old leaves that have mold buildup, over pruning taller palms so that they have a bit more breathing room. My success thus far has been very limited. The only thing I can think of is to continue over pruning each palm, then spraying the whole thing down with malathion and going onto the next one. I’m not a big fan of hard-core chemicals, but I do know that this one works. I would love any advice from people have experienced the same problem. Interestingly, not all species of plant seem impacted. It grows like crazy on some, not at all on others. Anyway, a couple of pictures… Thanks for looking!

[happypalms]

 A lot old time gardeners used to get the soapy water from either the bath or washing and the kitchen sink and throw that over the citrus trees to control the scale and the sooty mould it was the detergent that they where after in the water or it could have been the oil in kitchen sink water not how this will go for palms but my grandmother used to do it.

[Tracy]

5 hours ago, quaman58 said:

Hey all, the past couple years I’ve had some terrible outbreaks of sooty mold, but this year is the worst. My understanding of it is that ants farm scale and mealy bug for the honeydew that they produce. I have always assumed that the excess honeydew then falls to the ground, unless something like a leaf intercepts it. Then you have a perfect syrupy medium for the mold to grow. So the theory is, control the ants and you control the sooty mold. Somebody can feel free to correct me if I’m wrong. Do I see ants and scale insects? Yes. There is it appear to be a big enough problem to create the secondary issue? Not that I can see. Regardless, I’ve spent the entire spring and summer cutting off old leaves that have mold buildup, over pruning taller palms so that they have a bit more breathing room. My success thus far has been very limited. The only thing I can think of is to continue over pruning each palm, then spraying the whole thing down with malathion and going onto the next one. I’m not a big fan of hard-core chemicals, but I do know that this one works. I would love any advice from people have experienced the same problem. Interestingly, not all species of plant seem impacted. It grows like crazy on some, not at all on others. Anyway, a couple of pictures… Thanks for looking!

It is a frequent battle for me.  When I get really motivated or my wife complains, I use a mixture of Neem oil and a soap in a sprayer which helps.  I feel it is a little less toxic than malathion.  My problem seems worse during periods of heavy marine layer with few hours of sunlight breaking through. 

[Billeb]

7 hours ago, quaman58 said:

Hey all, the past couple years I’ve had some terrible outbreaks of sooty mold, but this year is the worst. My understanding of it is that ants farm scale and mealy bug for the honeydew that they produce. I have always assumed that the excess honeydew then falls to the ground, unless something like a leaf intercepts it. Then you have a perfect syrupy medium for the mold to grow. So the theory is, control the ants and you control the sooty mold. Somebody can feel free to correct me if I’m wrong. Do I see ants and scale insects? Yes. There is it appear to be a big enough problem to create the secondary issue? Not that I can see. Regardless, I’ve spent the entire spring and summer cutting off old leaves that have mold buildup, over pruning taller palms so that they have a bit more breathing room. My success thus far has been very limited. The only thing I can think of is to continue over pruning each palm, then spraying the whole thing down with malathion and going onto the next one. I’m not a big fan of hard-core chemicals, but I do know that this one works. I would love any advice from people have experienced the same problem. Interestingly, not all species of plant seem impacted. It grows like crazy on some, not at all on others. Anyway, a couple of pictures… Thanks for looking!

Bret, I haven’t got sooty mold in awhile but previously I sprayed with Malathion as you stated. Sometimes it took a few applications but it would eventually change from its sticky state to a more powdery consistency. Then I’d simply spray it with a water hose. I’ve had pretty good luck. 
 

-dale 

[Billy]

Bret, I've gone through similar bummers recently. I've had the same experience as you in the way that this issue does indeed tend to go nuts on certain species while others go completely unfazed. I reluctantly (and prematurely) removed 2 fronds off my biggest Cyphophoenix elegans about a week ago er so.  I always try to keep up on it just by using paper towels and windex to clean up the leaflets but I was out of town and haven't been able to be as pro-active as I would have liked. Ants don't seem to be too keen on the windex which seems to help put a stop to the scale farming that those little guys do. Everyone's got their own way to go about it though. Best of luck this growing season. 

[quaman58]

Thanks all for the helpful comments all. So here’s an observation that seems to be at odds with the root cause of this. I have some taller palms that are assessable from my balcony. (D. pembana & arenarium). They’re the tallest palms around, have little to no insect problems and have this mold. I don’t get where it’s coming from. Kooky.

[Billy]

I can't recall the pembana as there was so much to appreciate but do remember drooling over the D. arenarum. It's so tall yet so beautiful my neck hurt from staring so long. Definitely bizarre and a bummer that they also have that kooky mold. Fingers crossed that the issue subsides sooner than later. 

[tinman10101]

so ive learned from a very well seasoned grower awhile back that if you kill all the ants in your garden, you get rid of the 99% of all the pests in your garden ... with that being said, my go to for ants, mealy bug, scale, blah blah blah issues has always been a mixture of malathion and horticultural oil mixed together.  it has worked like clockwork for me and the great thing about it is, it kills on contact the pests with the malathion and then the horticultural oil will smother the aphids, scale, mealy bugs and all the other stuff it doesnt kill on contact.  

now to get to the root of the problem i believe that ants, anyways in my garden,  has always helped nursed and protect those pests.  my go to for that has always been termidor.  i bought a bottle in 2009 as a newbie and i still have it.  i swear by this stuff ... it works like magic and i spray very very very very responsibly.  PLEASE DO NOT SPRAY NEAR BEES ...it is not nice to bees and their colonies and other helpful insects so i am very cognizant of that when i spray.  i spray only early in the morning when there is no wind and no insects buzzing around.  its the stuff the exterminators use and many times, exterminator solicitors come knocking on my door only to find that i am using the same stuff they are using.  i do a regimen of spraying termidor once a year around the walls of my house where it meets the foundation and all doors and window perimeter.  never had crazy issues with ants or other pests and when i do see ants, i use it right away on their trails.  it doesnt work on contact but is slowly toxic and they spread it to the colony.  they are mostly gone the next day and i probably wont see them again.  i do have my neighbors that do not take care of their ant issues so i kindly spray for them.  i do not let them spray it because they are probably not responsible enough to use it and will spray all other helpful insects on a super windy day.

so that is my piece of advice that ive stuck to for 15 years. ...  yes i do use other stuff for issues with agaves and aloes but malathion mixed with horticultural oil (or neem oil) and routine spray of termidor has proven really helpful at my oasis.  

so bret. possibly try the malathion with horticultural mix on your super tall palms and work your way down. i hope that helps ... i know malathion smells like gasoline and my wife curses when i use it but she isnt complain when she is enjoying our pest-free yard 😉

btw i never had that mold stuff or at least dont recall but just trying to impart some of my own experience

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