Presumed recurrent fungal infection on Trident Maple

[markyscott]

I reached out to Matt Ouwinga and he felt pretty confident that it was a systemic fungal problem. He made the excellent point though that you only get good absorption of a systemic antifungal if you have a healthy, large leaf canopy to draw up the treatment. Essentially, he believes you need to outgrow it by increasing vigor of the tree. Spraying the leaves will not achieve any benefit. He advocated being super diligent water usage and using very dilute fertilizer to try and increase growth.

I agree with Matt. Very difficult to treat by spraying once the fungus enters the soft tissue and very difficult to treat systemically if you don’t have very many leaves. The disease progresses by first infecting the soft growth on the extending shoots. It’s treatable at this stage. It then involves the branch and can eventually infect the vascular tissue of the plant. Much more difficult to treat at this stage. I wrote an article some time ago that you might find useful.

S

 

[Lars Grimm]

I agree with Matt. Very difficult to treat by spraying once the fungus enters the soft tissue and very difficult to treat by systemically if you don’t have very many leaves. The disease progresses by first infecting the soft growth on the extending shoots. It’s treatable at this stage. It then involves the branch and can eventually infect the vascular tissue of the plant. Much more difficult to treat at this stage. I wrote an article some time ago that you might find useful.

S

I've read that article like 10 times so far. Great stuff!!

 

[markyscott]

I've read that article like 10 times so far. Great stuff!!

Great! I’m glad you found it helpful. Keep us updated on your progress!

S

 

[Estonio]

After reading this thread, I checked in 2 of my newly acquired palmatums

Not sure if fungal or not... Might be just climate or not proper watering for the last weeks... I'm not able still to distinguish even after reading @Smoke post...


First one
View attachment 250870
View attachment 250871

Second one
View attachment 250873
View attachment 250872

@markyscott any idea about this one? Might be also same fungal disease?

 

[Lars Grimm]

Great! I’m glad you found it helpful. Keep us updated on your progress!

S

@markyscott One question I keep coming back to though in the write up is the line, "How to Treat Anthracnose: When an attack occurs, respond immediately. remove all affected shoots and burn them." Is the idea that you remove affected areas only if you can do it very early to prevent spread? You and others have also advocated not defoliating affected areas in this thread as well so I am just trying to get a good gauge of when to remove affected areas.

 

[markyscott]

@markyscott One question I keep coming back to though in the write up is the line, "How to Treat Anthracnose: When an attack occurs, respond immediately. remove all affected shoots and burn them." Is the idea that you remove affected areas only if you can do it very early to prevent spread? You and others have also advocated not defoliating affected areas in this thread as well so I am just trying to get a good gauge of when to remove affected areas.

I’ve gone back and forth on this recommendation myself. I see it as a trade off - on the one hand, removing the leaves likely helps reduce the probability of reinfection. On the other hand, defoliation definitely weakens the tree. Your tree is already very weak. I think I’d avoid weakening it further by removing leaves. Hence the suggestion to not defoliate.

S

 

[Lars Grimm]

I’ve gone back and forth on this recommendation myself. I see it as a trade off - on the one hand, removing the leaves likely helps reduce the probability of reinfection. On the other hand, defoliation definitely weakens the tree. Your tree is already very weak. I think I’d avoid weakening it further by removing leaves. Hence the suggestion to not defoliate.

S

Are you suggesting there is no one-size-fits-all rule for bonsai?!?!? Blasphemy!

 

[Lars Grimm]

@markyscott A couple quick follow up questions for you.
1. When you apply a systemic do you just water it in similar to fertilizer or do you dunk the whole pot in the solution?
2. In your write up you mention, "Fungus may live in ground and leaf litter, so remove dead foliage and weeds from the container. Don’t let fungus, mold or moss build up on the trunk." I know you are a big proponent of sphagnum moss as a covering, but do you remove it in the winter?

 

[markyscott]

@markyscott A couple quick follow up questions for you.
1. When you apply a systemic do you just water it in similar to fertilizer or do you dunk the whole pot in the solution?
2. In your write up you mention, "Fungus may live in ground and leaf litter, so remove dead foliage and weeds from the container. Don’t let fungus, mold or moss build up on the trunk." I know you are a big proponent of sphagnum moss as a covering, but do you remove it in the winter?

Hi Lars. I apply Cleary’s in the granular form. I just put it on top of the soil surface and water it in. I clean up the soil surface in winter and reapply milled sphagnum.

S

 

[Smoke]

Hi Lars. I apply Cleary’s in the granular form. I just put it on top of the soil surface and water it in. I clean up the soil surface in winter and reapply milled sphagnum.

S

You guys putting all this litter on your soil is the No. 1 reason for fungus. Put lava and problem goes away.

 

[hemmy]

According to my county water report the pH average is 7.4-7.5. So maybe pH really is a bit of a problem for me. My understanding is that I want it ideally in the 6.5-6.8 range.

https://durhamnc.gov/ArchiveCenter/ViewFile/Item/4379

I think your issue has been correctly identified as fungal. But I looked at your water quality link and was shocked. You have great water, but I was surprised at your very low Calcium, 5.1mg/L (mg/L=ppm). You also have really low alkalinity and hardness, which means your water has low buffering capacity and will not do as much to change your soil/substrate pH even though your water is slightly alkaline (>7.0pH). Below is a link to a University of Arkansas paper on nursery irrigation water quality.

Back to the Calcium, your level is below the 40-100ppm guideline. If you aren’t seeing an issue, maybe your fertilizers provide enough. But I would ask around at a knowledgeable nursery or county extension agency to see if they recommend adding lime to their potting mixes.

https://www.uaex.edu/publications/pdf/FSA-6061.pdf

 

[Lars Grimm]

You guys putting all this litter on your soil is the No. 1 reason for fungus. Put lava and problem goes away.

I think this may have contributed over the winter. I moved into a new house in the fall and so I just mulched over my larger trees and left everything in place. I suspect this created an environment that was less than ideal even though I did spray with lime sulfur. My soil mix does include lava rock.

 

[Lars Grimm]

I think your issue has been correctly identified as fungal. But I looked at your water quality link and was shocked. You have great water, but I was surprised at your very low Calcium, 5.1mg/L (mg/L=ppm). You also have really low alkalinity and hardness, which means your water has low buffering capacity and will not do as much to change your soil/substrate pH even though your water is slightly alkaline (>7.0pH). Below is a link to a University of Arkansas paper on nursery irrigation water quality.

Back to the Calcium, your level is below the 40-100ppm guideline. If you aren’t seeing an issue, maybe your fertilizers provide enough. But I would ask around at a knowledgeable nursery or county extension agency to see if they recommend adding lime to their potting mixes.

https://www.uaex.edu/publications/pdf/FSA-6061.pdf

Thanks for the thoughtful review. I actually got a decent electronic pH meter and after calibration it says that my home pH is 6.8-6.9 so no worries there. I'll read through that paper a bit later. Thanks for sharing.

 

[Smoke]

I think this may have contributed over the winter. I moved into a new house in the fall and so I just mulched over my larger trees and left everything in place. I suspect this created an environment that was less than ideal even though I did spray with lime sulfur. My soil mix does include lava rock.

Not necessarily in the mix just as a top dressing. Needle pluck a pine and leave needles in the pot and you will have needle cast within 30 days. No litter in pots...

 

[Lars Grimm]

Finally getting some nice growth that so far is disease free. Of course now we are getting rain non-stop, but we shall see. I think a combination of the granular 3336, the light shade, and the moderate fertilizer has allowed me to push through the infection. Thanks for the help from everyone!

 

[Estonio]

U did not use any Copper oxychloride?

 

[Lars Grimm]

U did not use any Copper oxychloride?

I tried some copper spray early, but it didn't seem to really help. I think the systemic 3336 was the most helpful in my case.

 

[Estonio]

I tried some copper spray early, but it didn't seem to really help. I think the systemic 3336 was the most helpful in my case.

I think the 3336 is based of metil tiofanato 50%.

In Spain and maybe in some other counties we don't have 3336 but with the same component:

METIL TIOFANATO 45%;

PELT
CERCOBIN 45 SC
FRUITGARD M
SALVATOR

Can be interesting from folks outside US, if I'm not mistaken.

I'm glad to know this helped you as can also help for some others or myself given to the point.
Thanks

 

[cmeg1]

@Adair M showed me this Bonide Infuze granuals.
Same as Clearys.For smaller quantities.
So much easier...Sprays are extremly annoying especially when it gets on my arms!

Amazon.com : Bonide Infuse Disease Cntrl7.5# : Outdoor And Patio Products : Patio, Lawn & Garden

Amazon.com : Bonide Infuse Disease Cntrl7.5# : Outdoor And Patio Products : Patio, Lawn & Garden

www.amazon.com

 

[Lars Grimm]

@Adair M showed me this Bonide Infuze granuals.
Same as Clearys.For smaller quantities.
So much easier...Sprays are extremly annoying especially when it gets on my arms!

Amazon.com : Bonide Infuse Disease Cntrl7.5# : Outdoor And Patio Products : Patio, Lawn & Garden

Amazon.com : Bonide Infuse Disease Cntrl7.5# : Outdoor And Patio Products : Patio, Lawn & Garden

www.amazon.com

I've had problems also in the past with some chojubai that were down wind of the spray and dropped all their leaves as well.