I love the bark color of my recently acquired ap bihou (last year) but I was surprised by the amount of twig die off this spring, and alarmed at the black color of the twiglets at the top of the 50" skinny tree. Have not seen anything like this on my other ap, ac, or as....and while I'd never before heard of black twig disease, I saw the words someawhere, and they immediately made sense, especially as they were associated with red bark maples. Is there anything I can do or is the tree contaminated beyond hope? Does it spread easily? The Bihou is near a beni kawa and a pacific fire (ac)....
Hi Deb, First thing, don't worry about contagion. What you describe sounds like a bacterial infection, typically caused by one of the pseudomonas bacteria. One of the oldest life forms on Earth, funnily enough. Second thing, where Bihoo is concerned "can anything be done" is sort of an existential question. I think we should change the name of the tree to 'Boo hoo'. I got mine from a Boskoop nursery well known for selling clean plants; the owner told me he was going to stop grafting it because of so many problems. The stock plant looked just awful. For a couple of years I thought I was getting away with it, but the attached pictures show what happened over this winter. I think it's cooked. I've been treating this tree with copper regularly as a preventative, and of course even more so now that it's shown these infected areas, which sadly are not restricted to the base although those are the ones that will likely kill it. So, treat with a copper based solution and make sure the drainage is _really_ good is all I can recommend. I recall 'Pacific Fire' is pretty susceptible, as are many circinatums, although I don't grow it. -E
Boo hoo...is right. Didn't like the look of the tree, read that circinatums are susceptible and my pacific fire is over 10 years old, no way I wanted to endanger it...so i...ripped that Bihou out of the ground and direct-deposited it into the trash can in the garage... Glad you warned me about Bihou health issues as I was ready to buy another today: I just love that bark color but right now I guess it is Too Good to be True, alas...
Wow, you are a decisive and determined individual! :) Well done. I can never make myself do that sort of thing and end up with a table full of dead maples I'm still hoping will recover... After our warm winter followed by a really cold spring a lot of smaller seedlings have died, but I'm still hoping they'll recover! cheers, -E
Just paranoid about my healthy ones :-) of course, this was before I got your note saying not catching...so now I am confused, as someone somewhere else wrote they lost 3 trees before the copper got the issue controlled. I inferred that contagion was involved...can you help me understand better?
I don't know if I can, but will try to convey my understanding of it. Pseudomonas are fairly omnipresent, they arrive with rainfall certainly. There are theories that they are _responsible_ for rainfall, even. One of the clever thing the beasties can do is actually lower the temperature of water by a little bit. So when it's hovering near freezing, they cause local ice crystals to form on the skin of the plant, then enter the cambium through the tiny wounds caused by the ice nucleation. Once in, they thrive in the environment and multiply, which clogs up the vascular processes and causes tissue death. So if conditions are good, since they're pretty much all over the maples in the cold and wet, they can infect multiple plants at the same time, or serially. They're an object of much current study in the scientific world, so we can hope that more about the mechanisms and roles of the bacteria (there are lots of species) will be discovered. Count your blessings: you live in a great place for JMs with hot summers and cold winters. The danger time for pseudomonas is when it hovers around freezing with lots of damp, in other words winter (or sometimes all four seasons) here in mudville. So for me this is a constant battle, and if I don't systematically spray everything with copper, I really pay the price. The other thing is that pseudomonas are especially good at entering thin, or unripe tissue, that's why they love cultivars like Bi hoo etc. So if you fertilize too much and get a lot of soft new growth at the end of the season -- i.e. still growing in september -- that doesn't get a chance to ripen, it's very likely to die back over the winter. (Even from cold in your neck of the woods, not to mention disease). So with the susceptible plants it's a good idea to be really careful with the nitrogen. Most maples harden up once a stem is a few years old, apparently that isn't the case with 'Boo hoo.'
Thank you so much for this (ice) crystal clear explanation. I have about 30 cultivars and hadn'the seen this, so I do feel lucky! And now I may try beautiful temptress Bihou again...
To add to what has already been addressed so throughly. Do not prune coral bark varieties over winter, as doing so causes black tips. With the bad reputation of bihoo never pune it then start pruning other trees in your collection, as doing so can pass an infection on to other maples in your collection, even when the tree appears perfectly healthy (applies to new trees too as in todays trade you never know what bad habits you are purchasing from a grower or nursery, no matter how good they claim to be. All it takes is one bad apple and the whole basket turns bad). This is one of the biggest problems in the industry and in home gardens in spreading the disease. Its reccommended that you sanitize between pruning cuts before you move on to a new tree. I go a step further and have dedicated pruners for known sick trees. The reason is that the bacteria may gather in an area of the pruner that maybe difficult to 100% sanitize. Even products that are antibacterial say they clean 99.9% as nothing is absolute when dealing with bacteria. I use antibacterial and alcohol that is above 90%. The reason I don't use bleach is that I am fanatical about my pruners being pristine and bleach can dull and rust pruners. When pruning bihoo keep you pruners clean, sanitized, and sharp (great tip when pruning any maple). Prune only in mid to late spring. Try to prune only new growth to limit large trunk or branch wounds. If you keep up on pruning new growth that is not sustainable you will never have to prune anything larger than a pencil thick, except for cases of disease or storm damage. This will keep your maple looking its best and the bark free of big slow healing wounds that not only look bad, but invite pest and disease. (again all of this should be applied to all maples in my opinion and not just bihoo and other coral barks but all maple trees).
I did not wat to take away from the good information in my post above. So, seperately for those who are interested (otherwise skip what I write below and pay attention to my post above) If you are involved in the trade I invite you to read below and consider the following: My 2 cents worth mentioning... As mentiond before this bacteria has little research in botany, as a lot more could be done to fight the disease. But good knowledge and practices are available. The bad and ugly. .. Based on what I know about the maple industry of growing understock practices, grafting practices, and maintenance practices. Its my opinion that human involvement and decisions or lack of knowledge of disease or simply choosing to put resources above good practice is the number one cause for the spread of bacterial infections. This applies to not only human involvement in the growth of maples in the nursery setting, but the inherited problem continues on to the end consumer. Then sometimes the end consumer is not educated from the source they buy the tree, which only compounds the problem. This is just my frustration coming out from what I see in the industry. Then on here, when I am sad to see another person who paid good money for a tree saddened by its decline, I knowing that the problem most of the time existed before they ever got the tree. This is not true in all cases, only most cases. This is not intended to offend or give those who do a great job in the industry a bad name. Their are those who do a great job growing a great product, and those who sell to consumers and do a great job educating their customers. To those who know what they are doing wrong but use the excuse of time, money, or gotta feed the family; be offended if you want...I challenge you instead to make a change! Take the time to educate yourself, check out your sources to make sure they are doing things right and make sure your employees are educated and doing things right. It all starts with you! You have a big part in correcting this widespread problem. Don't be part of the problem, instead be part of the solution. Judge me if you want, but ask yourself first if you are doing right to the industry and your customers or contributing to the problem. Remember, copper spray or chemicals are not effective at treating the industry's problems, it only helps mask them at best in most cases. Copper spray and chemicals can't clean up your mess. Clean practices at growing and grafting is the only real solution. Educate yourself, employees, and then the consumer. Maybe only 1 in 100 will read this if I'm lucky, but I feel a little awareness may change a big industry problem. Its must start somewhere and I am willing to risk my reputation for real change. Its easy to do when you have right on your side and you genuinely care and have love for what you grow.
Most of our problems with internal Pseudomonas comes from our propagation techniques, not from the soil or airborne carried bacteria. Clean up our rootstocks by growing our own selected seedlings and have some quality control over which ones we choose to graft onto. More importantly choose clean budwood and not select just any wood to use for grafting. For this cultivar our growers and others are going to have to learn how to Spring and Summer graft and then choose vigorous wood, graft it and then monitor those plants to see if the symptoms of disease show themselves as readily as doing Winter grafting has. As dirty as this cultivar is and has been, grafting vigorous wood is probably the best savior if we want to keep this Maple in cultivation over the long term Jim
Jim,a few years back someone here took the trouble to get their Bi Hou diagnosed(can't remeber who)...it came back as some sort of Alternaria.I have no knowledge of this fungus but do you think it's likely?
Yes, right on about understock, Jim, it's one of my pet peeves. In the case of my Bi hoo, the grafter does grow his own understock and it is pretty clean compared to most, but not always so. And John is of course absolutely on point about disinfecting secateurs, I don't know how I missed mentioning it especially when I walk around with a jar full of rubbing alcohol when pruning... Indeed it is a primary way to spread the infection. -E
As I remember it Alternaria is a leaf spot disease on Maples. Yes, it can be diagnosed on a plant but this fungus alone is not what kills Bihou but it certainly can suppresses the growth of Bihou making the growth rather unsightly. In conjunction with Verticillium and Pseudomonas, the plant does not have much of a chance to survive for any real length of time. Jim
I'm glad you mentioned this as I was thinking that a fungus could not be the cause of death. It made me wonder if a over story tree had the fungus, or their was cross contamination at the lab...who knows...But it would add stress to the tree if the leaves had a fungus outbreak which would allow for the colony of bacteria to multiply under this added stress (especially in the case of a tree that completely defoliates) and the bacterial outbreak would be the cause of death as I understand it.
Thanks for the replies Jim&John.I must admit the symptoms don't look any different to any other maple,just more often on Bi Hou.Just surprised the other diseases weren't mentioned.
