Please help identify this disease!

Discussion in 'Maples' started by Chasingclouds, Apr 13, 2018.

  1. Chasingclouds

    Chasingclouds New Member

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    Hi everyone, I am absolutely desperate for someone to please help me identify what could be wrong with my acer palmatum ‘Koto No Ito’

    It has these weird marks all over the upper side of all its branches. I was thinking it must be some sort of fungus? The weird part is that the underneath of all those same branches are perfect and unmarked. I’ve tried to show this in the photo of the green underbranches. When I’ve wiped a branch with a wet cloth the white part of the marks is wiped away but the marks are all still there, darker underneath.

    I am at a complete loss as to what it could be, my local garden centre is clueless and I am desperate to not lose my beautiful tree.

    Thank you so much in advance for taking the time to look for me. Any and all advice gratefully received.
     
  2. JT1

    JT1 Rising Contributor

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    This could be a few different possiblies:

    -frost damage- frost hits the upper side of the branches and puts a series of cracks in the bark. By Spring it becomes more visible as the freeze thaw cycle over winter furthers the damage. The black is areas of deasd tissue and possibly bacterial infection as a result. Keep your tree healthy and these wounds will close over time as the branches thicken and wound tissue closes up the damaged area. When possible protect your tree from late season frost. Most trees if kept healthy will do fine and the damage is just cosmetic. Neglect your tree during Summer drought and these areas can fester into larger bacterial outbreaks that can cause branch or twig dieback and if the infection gets into the trunk, then it's possible to loose the tree. Avoid high nitrogen, chemical lawn fertilizer, and or weed and feed as this will weaken the immune system and make your tree more prone to bacterial outbreaks, cracks in the trunk, and even death. Best advice is to avoid chemical fertilizer and weed and feed products or urea based nitrogen. Do not use round up products around your trees. Use a balanced organic based fertilizer. Avoid nitrogen after August in most areas and late season pruning as this limits the trees ability to hardening off before winter and can effect winter hardiness. Maintain a regular watering schedule during the growing season to make up for any rain deficit especially during drought and summer heat. Consider protecting your tree from late season frost especially while still young and the bark is thin, as the tree matures and bark thickens this will not be as important as the bark stands up to frost better with age.

    -Bacterial infection Pseudomonas can cause spots in young branches and as the bark dies it becomes grey and flakes away. Information above about prevention, products to avoid, and limiting stress applies.

    -Winter sun or sun scald can cause damage but is less likely given your climate.

    -Chemical burn from overspray can cause spots or burns on the bark.

    In addition to my advice above it's important not to stress or overreact. Your tree is leafing out and that tells me it's doing fine. Most of the time this is just a little bump in the road. The tree will continue to grow and over the next several years these spots will no longer be noticeable as the branches and bark thickens as they mature. Once the tree leafs out you will hardly notice those spots.
     
    Last edited: Apr 14, 2018
    maplesmagpie and Chasingclouds like this.
  3. Chasingclouds

    Chasingclouds New Member

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    Thank you so much for the reply, it’s very gratefully appreciated. I don’t ever fertilise, or use any chemicals of any kind on anything in my garden, only water, but we did have a very unusually extremely cold spell here around 3rd March that was so severe even the media were calling it the ‘beast from the East’ where bitterly cold winds and below freezing temperatures, snow, hail, everything, and it lingered for weeks, so frost damage seems to make logical sense. I did move the most delicate of my plants into shelter as best I could but this was one that had nowhere to go. I was thinking it would be a good idea to buy some extra fleeces or similar to wrap the branches with for the next winter.

    I am so relieved to hear my tree should recover well if I look after it. I was very concerned it was some kind of disease and I should be doing something. I will definitely do my best to keep the water levels consistent all year.

    You mentioned a possible bacterial infection - does that need any specialist treatment or do I just leave it alone and keep stresses at an absolute minimum and the tree will recover itself in time?

    Thank you so much again for your time.
     
  4. JT1

    JT1 Rising Contributor

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    Yes, keeping stress at a minimum is best.

    Some people us Bordeaux mixture. This mixture is made by mixing copper sulfate and spray lime. Others use copper sulfate on it's own. I had used lime sulfur in January, but this is no longer sold to consumers. I find copper sulfate or Bordeaux mixture just is not effective despite the fact many use it. I find the best product is an organic antibacterial antifungal called neem. Here they sell a water soluble solution for hydroponics like
    Monterey LG6140 70% Neem Oil 16 Ounce. The product is mixed with water and can be sprayed on to the area (try to avoid spraying leaves as spotting can occur) and watered into the roots. To effectively stop the infection from spreading you need to attack it topically and systemically. We use it to stop a bacterial infection from spreading. They tend to start to appear in late winter as things start to thaw (in my area this depends on weather and can occur from late January into March). An outbreak can also occur during the growing season during the hot and dry Summer months. Or anytime the soil remains too wet for a prolonged period or when the tree is suffering from drought stress. Dried neem leaves can also be used to brew a tea that can be watered into the roots. When using neem, what ever the roots don't take up will break down into a mild fertilizer. As a precaution do not use synthetic or chemical fertilizer as these forms of nitrogen act as a food source for bacteria and the forced growth weakens the tree and opens it up to pest and infection. I know you don't use them, but wanted to mention for those who may.

    If the black areas appear larger or start to show up in other areas then treat the tree. Otherwise just monitor the tree during peak times. From what I could see in the pictures it looks like no action is needed.
     
    Last edited: Apr 15, 2018
    tiko7 and maplesmagpie like this.
  5. maplesmagpie

    maplesmagpie Active Member

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    Great responses, JT. Thank you. I learned a lot.
     

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