Here are some pictures of the branches of my Crimson Queen. It's been in the ground for about 5 years in full sun; I've never had any problems with it. A couple weeks ago, I noticed leaves throughout the crown dying- just shriveling up as though they were burned. Please note the weather has not been unusually hot here in the Seattle area. There are also many seed pods that are drying up. I took a sample, a rather dead sample, to my local nursery and the woman there was sure it was verticillium wilt. She cut into the branch and said she saw streaking (I saw absolutely nothing). She recommended I cut off all the dead branches, spray with neem oil in case there were also spider mites and to fertilize with a high nitrogen fertilizer. I did as she said. Upon further inspection, I've noticed this ugly white/gray splotching and discoloration on the branches and part of the upper trunk, mostly on the top sides. This is what the photos depict. Is it truly verticullium wilt? Maybe tight bark? I am still witnessing a bit of leaf curl throughout the tree, but more on the top.
From the information you give it is hard to be conclusive. As it is explained in the threads on Verticilium, symptoms caused by Verticillium develop anytime during the growing season, but are most apt to appear in July and August which seems to be your case. In some cases the symptoms may be more severe during or following cool weather. Symptoms appear chronically, or they may be acute and often lethal. Verticillium invades the root system directly or through wounds caused naturally by root growth through the soil or soil organisms. Once in plant tissues, the fungus produces toxins and invades the xylem (water conducting tissues), moving upward in the plant via spores. Where new spores lodge in the vascular tissue a new infection begins. Toxins produced by Verticillium may kill plant cells at some distance from those directly invaded. Thus, the fungus often cannot be isolated from the apex of streaked wood or from wilting branches, even though damage is apparent there In response to invasion by the pathogen, the host produces substances called tyloses or gums that attempt to close off the invaded cells to limit fungal movement in the plant. This shutting down of infected vascular tissues reduces the flow of water from the roots upward. At this point, reduced water flow and toxins often result in external symptoms. Wilting, interveinal browning, and leaf drop usually begin on one branch or on a section of the tree and progress throughout the tree. Dead and dying branches, sparseness of the crown, and reduced twig growth are frequently observed. However you will seldom see significant discoloration of the outer bark as this is a disease that affects the vascular system of the plant. Verticillium species cause discolored streaks in the sapwood that run parallel to the grain of the wood. In a slant cut the discoloration appears as spots or partial to complete rings in one or more growth rings. The discoloration varies with the tree species; in maples and smoketree it is grayish-green to olive-green. In maples, the Verticillium fungus progresses around a growth ring by a combination of upward spread and tangential growth. If the pathogen fails to cross from one season's wood to the next, the result is remission of acute symptoms and compartmentalization (containment) of the diseased wood. The severity of chronic symptoms depends upon the extent of root and old wood damage. Acute symptoms that recur after one year or more of remission indicate a new infection moving up from the roots. This pretty much summarizes what is known about the disease. It is up to you to make up your mind. The bark discoloration is most certainly not related to Verticillium, it may be an aggravating factor. It must be understood that symptoms of Verticillium may be accentuated by drought, inadequate nutrition, poor drainage, or other conditions that reduce tree vigor. Gomero
Year ago on my 4' Acer Triflorum top branches started to die. I had planted it maybe a month before and it was on sale. When I cut I found black circles. I remowed all until white wood and then some for winter and only one feet stub remained with some short branches. This spring I washed all the soil and planted it elsewhere. Then I feeded it with urea (47% nitrogen) diluted to water and also normal NPK but strong dose. With a lot of watering it has budded new branches which are healthy but thin and long. I expect many branch tips to die next winter because it propably does not prepare for a winter too well. At least those which stick from the snow might die when and if real freezes arrive on jan-feb. Usually my area lowest readings are -28C which equals ~-22F It was small enough to experiment. I also digged away a lot of soil around its first planting location which I buried deep with a lot of chalk powder. I suspect It was infected in the nursery at central Europe where it was nursed. Strong feeding with nitrogen combined with P and K as well boosts the growth. Those trees which live where winter is not too harch for them I would try anything to save.
Hello, Great summary of verticillium wilt, Gomero, thanks. I also question if that's what is going on here, although the tree may certainly be infected (as so many are). I have two trees with identical bark condition to that shown in Dr Cindy's photos. One is A. x conspicuum Silver Cardinal and the other is a Sango kaku. Both developed a large black spot on the trunk that did not propagate length-wise. The Sango kaku is near the base of the tree, and I was sure it would kill it; the conspicuum is on a branch, and I expected that to die off. However, neither tree seems to be effected beyond the bark condition, which seems to be the result of the original problem "healing over." Both the branch and trunk have grown in circumference and as far as I can tell there is living cambium under the wounded area. Both trees are showing good growth in spite of the very unfavourable conditions this year (cold and wet). I think it is a fungal problem caused by the very warm and wet winter, which has "cleared up" as things dried out (marginally -- massive chlorosis everywhere from lack of proper root function this year) a little. I would not fertilize more than normal, which is not much where these trees are concerned. HTH -E
If you would like, please post some photos of the branch tips and dried leaves from outside of the tree. Verticillium alboatrum may well be at work, but you have what appears to be the remains of a bacterial infection in the photos you show. It is very possible the bacterial infection is dormant this time of the year and is not directly related to your problem at the moment, but will do damage to the trunk, bark, cambium during the parts of the year it is active. Typical of dissectums presenting like yours, is to have a Tight Bark and Verticillum alboatrum infection causing havoc in the summer months, and then the bacterial canker that eats away at the trunk area in cooler wetter months. You can treat the baterial infection topically (pseudomonas) and you can try to help with the vert and TB through heaving pruning and fertilization with the goal being to have new unaffected growth emerge low enough on the plant that you can save it. In either case, the tree is usually left disfigured. While you might be seeing the worst symptoms this year, the infections are not new and have been present with visible signs for some time.
Thank you for all the posts so far. Everyone on this forum is so incredibly knowledgable. I've included a couple more pictures: one is of the entire tree, which as you can see is looking sparse on the crown since I did prune out dead branches. The other two are of the dying branch tips and leaves. Hopefully you can clearly see what I am referring to. I also hope this helps diagnostically. I gather from what everyone is saying is that I should prune out ALL the affected areas. Unfortunately, that would completely destroy the tree, since the discolored bark encompasses all the side branches. Any other suggestions or will the poor thing just slowly die? If it is most likely NOT verticillium wilt, should I even try another acer palmatum there?
Galt, I forgot to ask: what is the difference between Verticillium alboatrum and Verticillium wilt? I googled it but couldn't find anything I could comprehend :) And if the tree has a bacterial infection, how exactly do I treat it and with what? Thanks again.
The wilt actually causes the plant to "wilt" through a vascular collapse and loss of turgidity. The alboatrum is a very slow acting disease that simply plugs the vasculature preventing translocation of water and nutrients. Structurally, the vasculature remains intact. The former usually kills off the plant in short order where the latter rarely kills the plant on its own. The alboatrum is the verticillium you commonly associate with canopy dieback or unilateral or asymmetrical dieback in maples. In your situation, you have tight bark at work as well which constricts that twigs and branches and chokes off the new growth and buds as it emerges. In the branch tips, it prevents elongation and causes dieback. Where the tree needs to put out new growth to recover from the verticillium, the tight bark constricts the emerging growth so that we may see some buds emerge and leaves but the quickly die back or dry up. The only treatment from the above combination is to stimulate new growth, most usefully low on the plant, through vigorous pruning and controlled fertilization. There is no helpful chemical treatment. For the topical canker, simply use a copper sulfate in winter and spring. I am not sure it would be of any help with this plant. I would guess that you will continue to lose more wood than you gain in a season and eventually the tree with die. Along the way, its appearance will remain sickly, especially in the summer, but if not too badly disfigured, it might look pretty good in the spring. Sorry.
Galt, Thank you so much for the informatin and education. Thank you also for the condolences :( One last question: Is verticillium alboatrum similar to VW, in that it will live in the soil for years and kill any future maples? I just want to determine if I basically have to refrain from any more japanese maples in that spot once this tree succumbs.
Galt, To my knowledge (and I am not a Botanist or anything like that) there are in fact two species of Verticillium that may cause wilt diseases; Verticillium albo-atrum (that you mention) and V. dahliae. Both verticilliums naturally occur at low levels in soils and can attack susceptible crops when these are planted. V. albo-atrum grows best at 20 - 25 °C, while V. dahliae grows better at slightly higher temperatures at 25 - 28 °C. I have even read that hybridization between the two species has been demonstrated. Both verticilliums will overwinter as mycelium in perennial hosts, plant debris and vegetative propagative parts. However, V. dahliae will persist longer in the soil due to the microsclerotia, while V. albo-atrum does not produce these structures. Both fungi can be spread in contaminated seed, propagative plant parts, by wind, water and soil. Both exist as various strains or ssp. The host range, virulence and other characteristics of these strains vary considerably. Some strains have a very broad host range while others are quite host specific and some of the host ranges overlap. The symptoms due to both species are comparable and are as described in my post. In the literature search on Verticillium I have not come across a Verticillium species that produce the symptoms you describe: sudden death through vascular collapse and loss of turgidity. Could you provide additional information? Gomero
You can cross-reference the wilt form of verticillium to its effects on other crops to find the specific pathogen-which you have already touched on. The alboatrum form (one word) does not cause a wilt per se and the two types you mention do not present the same. Maples exhibiting the alboatrum form of Verticillium as depicted here in Dr. Cindy's tree do not acquire it from the soil, but nearly always through propagation-related channels.
Hi everyone, Just wanted to provide an update on my tree. I took a branch sample to another nursery. When they cut it open, there was a definite green streak down the center of it. They immediately stated it was phythphora, some sort of bacteria which is soil-borne, which clogs the vascular system, similar to that of verticillium. It apparently spreads more with watering! Like verticillium, I was instructed to prune off all affected branches, and cannot plant another Japanese maple should mine succumb. I was recommended to a product called Hydroguard to see if that would help. Applying Hydroguard was explained to me as being akin to undergoing radiation treatment for cancer- we can hope it will work, but it may not be a sure thing, and definitely not a cure. With regard to the white splotches, I was told it was simply lichen. They had some mature JM's in the nursery that had similar splotching and discoloration. However, they really did not have much knowledge of tight bark. One staff member had recently attended a master gardener seminar about pathogens and said they only skimmed over the tight bark subject, and she was told it was not prevalent at all here in the Pacific Northwest. So now I am still in the process of trying to save my tree and hoping the Hydroguard will help it somehow. I had to prune off a few more branches on the top, so it's looking pretty sparse. We shall see. Thank you again for all your input.
Cindy, I have been told phythphora can be treated with the product Aliette Express. I had a shirasawanum Aureum that was "diagnosed" by the Nursery with this. That was their recommendation. Turned out to be no help, the plant died, and the wood showed the tell tales of Verticillium. (And so was doomed regardless of the treatment.) I hate to say it, but I am wary of what I'm told in many nurseries. Often I know more about maples than they do. In your case, calling the white splotches lichen is simply wrong. Lichen I've got tonnes of, that isn't it. Tight bark is a controversial subject, but if it exists at all it is certainly in the NW. Unlikely it would be discussed at all by anyone outside of maple specialists? Now, I can't say that our two cases are the same, but the bark situation is identical if much more localized for me. And my two infected plants, having dried out (relatively speaking) are doing pretty well. For me, it looks like Pseudomonas syringae. I checked the Sango kaku again, indeed there is a part of the trunk where the cambium has died under the white, but there is is still healthy (and growing, good trunk growth) bark under a lot of it. In fact, it flaked off pretty easily in places. -E
Here is an update- I took several branch samples to my local extension office and the diagnosis is...Verticillium wilt. Although the wood did not show any telltale streaking signs, the culture of the wood confirmed it. If I ever have any more weird plant diseases on prized specimens, I'm definitely going to utilize the extension service again. It was well worth the $15 to get a definitive answer. And Emery, I agree with you in that I am also becoming more wary of what nursery people tell me! Now I have to dig up the poor tree...I'm going to put another dissectum in the area but in a pot and elevated because nothing else will look as stunning in that spot.
I'm a little late to reply, but thanks for this explantion Galt. Much appreciated from a relative newbie to Japanese Maples.
