Canker

(December 2012)

Can you tell from this picture what is causing the bark on this oak tree to fall off? This tree looks like it is dying and we would like to know what might be causing it. The tree is on a home site with five acres of hardwoods and pines in West Little Rock.

Your tree has hypoxylon canker.  This disease has been prevalent this year and will be next year as well--since it is common when a tree is drought stressed.  Typically by the time the outer bark sloughs off, the tree is half dead or more, and you cannot reverse the trend.  The underneath wood is either black and tarry looking or the gray powdery substance you have.

(September 2012)

If the bark is falling off from a part of a tree does that mean the tree has to be cut down because it is dying?  Could it just be pruned up to remove the damaged part and the tree be saved?

It depends on what is causing the bark to fall off, and the overall health of the tree.  Sometimes lightning can hit a tree and cause bark to slough off—damage can be minor or deadly.  Many oaks around the state are dying in part due to drought stress, but that can also cause hypoxylen canker to kick in.  When this disease takes over, the outer bark usually falls off in patches, exposing either a dry gray substance or a black tarlike one.  Usually by the time the bark falls off, the tree is either dead, or almost there.  Damage from a weed-eater or lawn mower can also cause bark damage, but usually too close to the ground to cut out without cutting down the tree.  Once bark begins to fall, you can’t stop it, but you can clean the wounded area and try to keep the tree overall healthy with proper watering.

(January 2012)

I have several beautiful Leyland cypress trees in my front yard that have done well for years, but this year I noticed one of them has a problem in the top. Something is causing it to look like it is dying. I was wondering if you could tell me what it is and if anything can be done before it is too late.

Did you water it the past two summers? We are going to have a lot of damaged plants—trees in particular after the past two horribly, hot and dry summers. Die-back from the tips, could be indicative of drought damage. If you are losing sporadic branches, this could be twig canker, a common disease they suffer from, but it usually doesn't attack just the top of the tree. If you can, take a sample of the plant and some photos to your local county extension office for diagnosis

(April 2010)

I have a Leyland Cypress that died last year, turning brown from the bottom up.    Now I notice two branches on a nearby Leyland that is beginning to turn brown.  Do I have bugs, fungi, parasites or chemical poisoning?  Or is the Leyland going the way of the red-tipped photenias?  Help.

I think the Leyland is going the way of the red tip photenias, but be aware that some red tips have not been affected by disease and some Leyland’s haven’t either, but disease is spreading on both plants.   There is a canker disease that affects Leyland cypress and there isn't much you can do once it hits. It is typically associated with some type of environmental stress.  All of our rains last season did not bode well for many of the needle type evergreens.  Here is a link to our fact sheet about the disease: http://www.uaex.uada.edu/publications/PDF/FSA-7536.pdf  If you are replacing the plants, I would consider other options--Emerald or Green giant arborvitae; cryptomeria, or one of the hollies.