What is this black stuff killing my customer's cedar elms?

Discussion in 'Fertilizers, Pesticides and Diseases' started by M50V, Jun 15, 2013.

  1. M50V

    M50V LawnSite Member
    Messages: 107


    I have a customer that is asking me what is wrong with his tree that is killing it from the top down and how to stop it and save his tree. These are Cedar Elms fyi. It is like a black fungus as you can see, but I am unsure what it is exactly. I am located in the central Texas area. Any idea what this is and how to stop it?



  2. M50V

    M50V LawnSite Member
    Messages: 107

  3. Colaguy

    Colaguy LawnSite Senior Member
    Messages: 599

    May be this but not sure. I think the tree in pic is to far gone to save.



    Hypoxylon canker is a fungus that causes cankers and death of oak and other hardwood trees. The disease is common in East Texas and all across the southern United States. Relatively healthy trees are not invaded by the fungus, but the hypoxylon fungus will readily infect the sapwood of a tree that has been damaged, stressed, or weakened. Natural and man-caused factors that can weaken a tree include defoliation by insects or leaf fungi, saturated soil, fill dirt, soil compaction, excavation in the root zone of the tree, removal of top soil under the tree, disease, herbicide injury, drought, heat, nutrient deficiencies, competition or overcrowding, and other factors. The hypoxylon fungus is considered a weak pathogen in that it is not aggressive enough to invade healthy trees. In addition to the hypoxylon fungus, weakened and stressed trees may become susceptible to a host of other insect and disease pests.

    Hypoxylon canker activity usually increases when prolonged drought occurs. When drought stresses trees, the fungus is able to take advantage of these weakened trees. The moisture content of living wood in live, healthy trees is typically 120% - 160%. It is difficult for hypoxylon canker to develop in wood that has a normal moisture content. However, any of the factors listed above could weaken or stress trees causing the moisture content of the wood to reach levels low enough for the hypoxylon fungus to develop. When this happens, the fungus becomes active in the tree and invades and decays the sapwood causing the tree to die. Once hypoxylon actively infects a tree, the tree will likely die.
  4. Smallaxe

    Smallaxe LawnSite Fanatic
    Messages: 10,082

    We have a bug that lives under the bark chewing up the cambium that kills the tree from the top down... Your fungus may not be the CAUSE of the dead wood ,,, but likely is the AFTERMATH of deadwood... I forget the name of the bug right now, but a systemic soil drench has taken care of it for our trees...
  5. phasthound

    phasthound LawnSite Fanatic
    Messages: 5,161

    Honestly, what do you know about trees, insects & diseases in Texas?
  6. Smallaxe

    Smallaxe LawnSite Fanatic
    Messages: 10,082

    I don't know... bugs don't eat trees in general all over the world??? is there a disease fungi that rots trees from the top down, or is it more likely that it feeds on dead plant material???
    Just as ,,, I don't know,,, that plants outside of CentroWisco get along just fine in poor soil structure w/out regard to tilth...

    That natural world is such a mystery to people who can't connect the dots and they are becoming overly tedious...
  7. phasthound

    phasthound LawnSite Fanatic
    Messages: 5,161

    The information posted by Colaguy was helpful.
  8. Smallaxe

    Smallaxe LawnSite Fanatic
    Messages: 10,082

    Our birch tree also has the black tar look in which the bugs came first...
    According to the article there was obviously a stress or "trigger" that allowed the canker to invade a , no longer healthy tree...
    Looking for those triggers is a good preventative measure,,, since there is no cure,,, is professional conduct that the client will appreciate...
    That is something that those who only mock others will NEVER understand... :)
  9. Think Green

    Think Green LawnSite Silver Member
    Messages: 2,746

    Regardless of what insect is eating on this tree or what disease is harming it, environmental issues is usually a problem. Urban trees are subject to too much difficulty to stay healthy. They must compete with grasses and compaction to survive for many years.
    The most common insect of any elm is the bark beetle....causing the ill fated DED disease, and the leaf beetle.
    You can peer under the bark of a stem or small limb but peeling off the outer bark and looking for black or brown streaks in the inner wood.
    I couldn't see a close up picture of the trunk as this is where to start as well as the surrounding drip line area. I often find where grade changes are made to the trees CRZ area. If you do not see any rootflares around the base of the tree, then the grade is wrong. Normally, when a tree, shrub,etc. starts dying from the top down, it is root related to the sap stream. Something internally is limiting the natural sap flow. Often, compact soils will cause toxic soil around the root zone or CRZ. IF the soil cannot breath to allow for natural gas exchanges, the root will die a slow death.
    To rule out a perfect cause, take samples of leaves, twigs, roots to your extension service and have them tested if the customer is really curious. Otherwise, I see no need to render this tree to further distress, just have it removed and the stump cut out or ground. If 50% of the crown and surrounding leaves are gone, then take it down.

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