Hi everyone, When I looked at my Bihoo, I've noticed some issues on two of the branches, and that got me quite worried. I have attached some photos When looking at the tree, it seems healthy (no wilted, or small leaves on the two branches that are affected, even on the one that has lots of dead wood on the side). The first photo shows the node area looking totally dead, and only 1/2 to 1/3 of it is still healthy and managing to keep the upper branch alive The second photo shows lots of black marks. Do you think it is likely infected by Pseudomonas? If so, is there a way to get rid of it? I've seen in old threads something about using Phyton 27 or 35 bactericide/fungicide for this, but it's not available in the UK. Would something like Provento Fungus Fighter plus help against it? On another place I saw someone used colloidal silver and seemed to have had success with it I was hoping to find a solution that doesn't consist in cutting the two branches (as they're quite long and would reduce the small tree by a lot). If that's the only solution, I guess I need to cut them earlier rather than later? I also need to be careful to not contaminate the other maples... Thank you for your help!
Hi Chris, Your maple is sick with a bacterial infection, probably pseudomonas as you suggest. In the first picture you see pruning where the too-short stubs died back into the main stem, enabling the infection. The second picture shows further possibly systemic infection. You have a limited number of options, and aside from bark surgery to try and cut out the infected areas (which I wouldn't try in these circumstances), all you can do is follow Alain's recommendation. Phyton27 is Bordeaux Mix, that's the main tool when this happens. I don't know of anyone spraying colloidal silver. I would spray every few days for a few weeks. Step 2 is also very important. (And step 3!) Good luck, -E
Thank you Alain and Emery for your replies I can't find Phyton27 in the UK as it's been banned, but I can find copper sulfate on amazon uk which seems to be what is in a Bordeaux mix. Is mixing 3 tbps of copper sulfate with a gallon of water enough (that's the ratio I've found on internet, is this the correct one? like in https://www.hunker.com/13406855/how-to-use-copper-sulfate-as-a-fungicide ), or is the hydrated lime definitely required in the mix? Many thanks, - Christophe
I believe the lime mostly keeps the copper on when it gets wet. I don't think it's an essential ingredient. Note, while copper is also a fungicide, you're after its properties as a bactericide here, because the attack is bacterial. Aside from copper your other effective option is horticultural antibiotics, which I really don't recommend! (If they're even sold in the UK. I guess I didn't look carefully, though you were in the US for some reason.) For the amount to mix up, follow the instructions on the box, use the maximum strength they propose. Cheers, -E
Thank you for the clarification @emery I'll try spraying for a few weeks, and see after that whether I have to go for the pruning option
That's a damn shame, hope you can save that tree! To learn: how can this happen? In this case, probably the pruning wound? How would one avoid that kind of issue?
My experience is that all of the coral bark types are more prone to these bacterial infections than the regular types, probably due to (1) thin or weak bark on young shoots and branches and (2) [related to (1)] a functional deficiency or imbalance in the bark plastids that makes the characteristic colour. The bacteria that cause the problem are widespread in nature and cannot realistically be avoided. The usual advice about sterilising pruning tools and making clean cuts should obviously be heeded. The other most important factor is to ensure the maple is as healthy as possible in the first place but not over fertilized - the softer the growth the more likely it is to become injured or die back and allow an entry point for the pathogens, and once they are in the soft growth is an easy food source. I bought 'Bi hoo' 7 or 8 years ago and wasn't expecting it to do much good given the reputation for dieback and health issues. With very little feeding, but enough watering, it has become a healthy, if not overly large maple, with very minimal small twig dieback every year. Almost benign neglect, but 'Bi hoo' seems happy with it.
My 'Bi hoo' has its own anecdote to tell... :) I bought a new graft from Dick van der Maat in 2011, and after 3 years of getting bigger, planted it in a spot without too much direct sunlight. BTW Dick told me he swore off Bi hoo, calling it a few names that don't bear repeating. I saw his mother plant, it was pretty covered with pseudomonas, though he may since have gotten a cleaner plant. My plant languished in the ground for a couple of years, and in 2016 froze badly in spring. There was literally a mm or 2 of live bark connecting the root stock and the top of the plant, the rest was a huge black wound. I'm a softy for maples and rarely give up on them even when I should -- a practice that's been very valuable this year, as I watch a few come back from the base after the repeated spring frosts -- so I bunged Bi Hoo into a 20l pot, sprayed it with copper for a few weeks, and forgot about it in deep shade. There it has stayed for the last 5 years, only lugged in and out of cover for the winter, and once repotted into a 35l. During the last couple of years it's been near the best looking of my JMs, which I confess sometimes look a little shabby as the season progresses, and the bark has healed most of the way around. The hole is maybe 20% of the circumference. I think almost any other maple, had it lived, would have healed by now. But it continues to be happy enough, and looks decent. This year I took it into some light and it has colored quite a bit, as all the maples have this year due to cold temperatures and wet. It still catches peoples eyes though. I'll get it back in the ground if it ever heals the rest of the way. So the answer is: shade!
Yes, mine is in shade too, but more dappled shade rather than deep shade. Never had any major branches die back or any lesions on the trunk, luckily. The coral bark I am fighting a battle with at the moment is 'Eddisbury' - planted in the ground with a decent amount of direct sun. I've been pruning branches off regularly the last couple of years and there is a wound on the trunk that needs to heal, but I am confident I will turn it around.
Thanks for all the interesting information in the previous posts! It really shows that we shouldn't give up with our maples when they are in trouble. I'll also have to look for a properly shade area I have another question: Is it better to 'spray' or 'paint' the dark/black zones on the maple with the copper sulfate solution? Does it also have to be applied quite far from the affected the zones? Thank you - C
Spray, spray and spray. When you pulverize, you make a fine mist of micro-droplets that can penetrate into very fine fissures. If it doesn't penetrate the first time, as you continue to spray your chances are increased. When you make a paste and paint it on, you can easily "paint over" fissures, which prevents the medicine from reaching the bacteria. Further, that layer blocks further applications, so the infection is protected. That's my story and I'm sticking to it! YMMV, lol.
