Systemic fungicide for queen palms

[palmluver]

I'm finally getting some healthy fronds on my queen palms.  I think I've got a handle on fertilizing needs (manganese, soil acidifier, etc).  They are getting a bit tall to easily apply copper fungicide to the crowns, though I am still managing it with a small powered garden sprayer.  At this time I would like to add a systemic fungicide to hopefully fortify them if there comes a point that I can't handle the crown spray.  I already lost a whole row of queens in another section of my property, so looking to do all I can to save these last 4.  (Short of hiring a tree company, which I also tried with the others but it was more expensive than just replacing the trees.)  So, I bought a fungicide call Heritage SC, active ingredient azoxystrobin.  The instructions include queen palms on the list of plants that will tolerate the fungicide.  My concern is how much to apply as a drench.  The instructions indicate a use rate of 1.7 to 3.8 oz per 100 gallons and apply 1-2 pints per square foot.  This comes out to .228 teaspoons (about 1/4 teaspoon) per gallon of water which sounds way too dilute.  Are these fungicides that powerful?  As for the solution application itself, I was figuring to apply 1 or maybe 2 gallons of drench solution to each tree twice a year (now and in the fall).  Does this sound reasonable?  Any advice appreciated! 

[Harry’s Palms]

I don’t know about a fungicide or any application techniques but I know it is far more difficult to grow there than here in a more temperate environment . I really think it is going to be a challenge moving forward to keep Syagrus R. happy in your climate. I just water mine and they grow like rockets , drop seeds everywhere if not trimmed regularly , and then volunteers sprout. The only real issue is they need regular maintenance, trimming to keep the mess down. Yours look as good as I’ve seen from your area . I suspect the heat of summer will set them back a bit once again. Harry

[palmluver]

Just an addendum.  I inherited all of these queen palms (13 in total) when I bought the house.  I wish that the previous owner had planted mule palms and not queen palms.  I came here from the Northeast, and I learned within a year of moving in (5 years ago) that queen palms are not suited for the Phoenix area, and all the reasons why.  Climate--heat, cold, deficient soil, fungus in the air, etc.  But we were reluctant to replace them all and start over.  After 4 years of struggle with the palms, I learned that the mule palm is a recommended substitute for queen palms and replaced 9 of our 13 queen palms.  We are sad that it will probably be around 5 years before our view of the neighbor's back yard is once again shielded from our view.  I didn't cut down these last 4 because they seemed to be doing better and 4 trees are (much) easier to pamper than 13.  

[happypalms]

Iam sort of wondering why you need to spray your palms they seem quite happy. If the rate from the manufacturer says 1 ml to a litre then what it is. You will be surprised at how powerful chemicals are. I work in the horticulture industry and have seen the mistakes of to much chemicals applied in the wrong rates. A systemic application could be through soil drenching or injection foliar application. My home garden I don’t spray it upsets the natural balance of Mother Nature wiping out symbiotic relationships. You don’t need to be exposing yourself to chemicals, think of your endocrine system please try to avoid chemicals, and think of the environment and waterways. 

[palmluver]

For those who may be wondering, Queen Palms are difficult to grow in my area (Phoenix AZ) and not recommended for this area by knowledgeable landscapers.  (I didn't plant these, they were planted by the previous owner and came with the house.)  They are especially susceptible to an air born fungus for which the gold standard treatment/preventative is a copper fungicide spray into the crowns.  I had this done by a tree company last year along with fertilization but it was so expensive I bought myself a powered garden sprayer and did it myself this year.  I did not like having the spray raining down on me during this process and so hoping that since the palms seem to be recovering I can get away with transitioning to a systemic fungicide that I can apply as a drench.  It is satisfying to hear that they look happy now, but they won't stay that way without the regular fungicide treatments.  

[Silas_Sancona]

36 minutes ago, palmluver said:

For those who may be wondering, Queen Palms are difficult to grow in my area (Phoenix AZ) and not recommended for this area by knowledgeable landscapers.  (I didn't plant these, they were planted by the previous owner and came with the house.)  They are especially susceptible to an air born fungus for which the gold standard treatment/preventative is a copper fungicide spray into the crowns.  I had this done by a tree company last year along with fertilization but it was so expensive I bought myself a powered garden sprayer and did it myself this year.  I did not like having the spray raining down on me during this process and so hoping that since the palms seem to be recovering I can get away with transitioning to a systemic fungicide that I can apply as a drench.  It is satisfying to hear that they look happy now, but they won't stay that way without the regular fungicide treatments.  

Yep,  as i'd mentioned to someone else in another thread yesterday,  had a discussion w/ a city aligned worker about this very subject.. Queens = worst palm option for the valley  ..Something folks who don't live here seem not to comprehend -at -all.  Kind of amazes me but, guess it's eyes wide closed for some people 24- 7- 365  i guess.. 


Unfortunately, the DIY approach w/ applying that stuff to crowns that high up will come w/ the risks of getting the stuff on one's self.. Not something i'd want anywhere near me personally. 

Applying on a wind-less day would be the only thing i can think of that might reduce over spray that could fall on you 🤷‍♂️

Fully respect that you want to save them, esp. after all you're doing to try and revive em' but, reality is nature will win this battle.. 

I myself would bite the bullet and slash an unnecessary expense. 

Regardless, good luck in which ever decision you decide on. 

[Phoenikakias]

What is the air humidity like in Phoenix AZ? I thought it must be low and I can not imagine how low air humidity may promote air born fungus. Instead I consider as decisively inhibiting factor soil and water alkalinity and lack of adequate organic matter in the soil. This may cause as secondary effect root fungus. I strongly recommend trichoderma treatment plus regular application of sulfur pellets, soil drenching with humic-fulvic acids and eddha chelated iron. And of course application of chemical fertilizers should cease unless you use reverse osmosis for irrigation. Here are some examples:

Below specimens display heavy deficiency and grow near my garden in same native soil but amended with brought in top soil. Owner committed the usual mistake, namely she treats problem with heavier fertilizing, which only worsens matter.

Then following specimen is belongs to me and it grows exclusively in the native, stony, alkaline soil in a slopy landscape. I follow the above treatment aiming at handling the pH issue. It has set fruit.

Below you can see two nice specimens, growing inside concrete but because of this very same reason receive less alkaline water and no fertlizer.

[palmluver]

2 hours ago, Phoenikakias said:

What is the air humidity like in Phoenix AZ? I thought it must be low and I can not imagine how low air humidity may promote air born fungus. Instead I consider as decisively inhibiting factor soil and water alkalinity and lack of adequate organic matter in the soil. This may cause as secondary effect root fungus. I strongly recommend trichoderma treatment plus regular application of sulfur pellets, soil drenching with humic-fulvic acids and eddha chelated iron.

The humidity here is not always low and can exceed 60% during monsoon season.  This is from an AI overview:  

Fusarium wilt is primarily driven by high temperatures and moist soil:

The pathogen, Fusarium oxysporum, thrives in warm conditions, and the presence of moisture in the soil allows it to spread more easily into the plant's vascular system. 

• Arizona's climate generally favors Fusarium wilt:

  The hot and dry conditions in Arizona can create a perfect environment for the pathogen to develop, especially if soil moisture is high or if there are periods of prolonged heat. 

I am already applying many of the items you suggest including sulfur pellets, soil acidifier, and chelated iron.  We also need to feed manganese and watch out for potassium and magnesium deficiencies.  I am also working on insuring periods of drier soil between deep soaks which is a recommendation for our desert area that discourages fungal growth.  My new addition is that I would like apply a systemic fungicide (which you also recommend) and I have purchased one but question the concentration required per the fungicide instructions which seems very diluted.  That was the subject of this topic.  

[Phoenikakias]

Have you confirmed through microscope the fusarium infection? I had during the past years several of my Latin American palms in my garden dying one by one (summarizing 2 Acrocomia, 2 Parajubaea, 1 Jubaea and another 2 Allagoptera nearly died but I managed finally to save them). So I called to help a retired Professor of phytopathology, who took samples of the deceased plants and occasionally the whole plant for autopsy under the microscope. He was hoping (from a scientific perspective of course) to trace the first confirmed outbreak of fusarium infestation among palms in Greece. Well it turned out that the killing fungi had been the not so exotic Thielaviopsis and Rhizoctonia. Each one of those fungi responds to a different kind of fungicide, Thielaviopsis to Thiophanate-Methyl and Rhizoctonia to Tolclofos (the alternative substance against Rhizoctonia  so popular in the USA having been for quite a time banned in Europe).  I began treatments with those substances for half a year, until I realized that this can and should not be a long term practice, since I was turning soil to a lifeless material. With trichoderma treatment remaining palms grow now better. I feel extremely lucky that I timely stopped using chemical fertilizers, because water quality has deteriorated due to the ongoing drought.

[palmluver]

8 hours ago, Phoenikakias said:

Have you confirmed through microscope the fusarium infection? I had during the past years several of my Latin American palms in my garden dying one by one (summarizing 2 Acrocomia, 2 Parajubaea, 1 Jubaea and another 2 Allagoptera nearly died but I managed finally to save them). So I called to help a retired Professor of phytopathology, who took samples of the deceased plants and occasionally the whole plant for autopsy under the microscope. He was hoping (from a scientific perspective of course) to trace the first confirmed outbreak of fusarium infestation among palms in Greece.

No, it hasn't been scientifically analyzed.  Unfortunately I do not have access to that type of specialist. I certainly appreciate the breadth of your knowledge on various types of fungi and  treatments they respond to, but it’s a bit more than I will have the time or resources to explore.  Rather than spending energy looking for a cause that is atypical of my area, I’d rather give a go at learning more about the problems most commonly seen here in Phoenix which include fusarium, crown rot, root rot, and common nutritional deficiencies, and the recommended remedies for those.  I am encouraged that my queens have started to improve, but if that reverses at some point then I will have the palms removed and replace them with something more suitable to my climate.