Diseases

December 9, 2017

I am finding branches all over my yard...a lot! Some elm, some oak. A Master Gardener told me it was some type of insect.  What kind and should I be concerned? 

Whenever we see small branches that look like they have been chewed off, it is a good sign that we have twig girdler beetles in action.  The female beetle girdles small branches usually a pencil or smaller in diameter and deposits eggs in these twigs.  She leaves the twig barely attached, so when we have wind movement these small branches fall.  Girdling usually occurs in late summer into fall.  Rake up and destroy the small branches, since they can contain the eggs or larvae.  No sprays are recommended. 

June 10, 2017

My oak tree has some type of insect or disease on it.  There is a spore-looking spots on the back of the leaves.  The spots are circular flakes on the back of the leaf, but there are also spots, and tiny holes, on the corresponding location on the front. The flakes fall off and have littered the deck beneath the trees. Can you identify them?  

It is actually another type of gall called jumping oak gall.  The small round button-like discs are on the undersurface of the leaf.  Each disc contains one wasp larvae that sometimes jumps after it falls off and lays on the ground.  Affected leaves will then have a small brown spot with a yellow halo on the upper surface. In early summer, when the larva is mature, the gall falls off the leaf leaving a brown pockmark. On the ground, the fallen galls may jump due to the movement of the larva inside the gall. This jumping helps the gall move into leaf litter or cracks in the soil where the larva will overwinter.  There is no treatment since by the time you see this, the damage is done and it is too late to control.  It is usually more a nuisance than life threatening.  The best thing you can do for your trees is to keep them healthy with regular watering when dry.  

November 21, 2015

I have an oak tree that has a mushroom like growth coming out of the trunk about ten feet off the ground.  I also have some dead limbs on the same side. Could the mushrooms be killing my tree? Is there something I can spray with to kill the mushrooms and save the tree?  Will this spread to other trees in my yard?

This mushroom-like growth is typically called a shelf mushroom.  It indicates that you have some internal decay inside the tree. The mushroom itself is not killing the tree, but it is an indicator that your tree has some problems.  Once a tree is infected, the fungus causing the mushrooms cannot be killed.  You need to assess the overall health of the tree. If only a few branches are dead, and the rest of the tree fully leafed out, it could be fine. The internal decay will continue to spread and depending on where the tree is located near your home you may want to have an arborist inspect it to determine if it needs to be removed.  

October 10, 2015

I wonder if you could help me figure out what is going on with my Leyland Cypress trees. There are a lot of brown branches throughout them. The damage seems to be random. They are about 10 years old and prior to this they have always been healthy. 

Leyland cypress trees are affected by several canker diseases. It typically starts appearing around 7-9 years of age, but you begin to see dying limbs scattered throughout the tree.  Pruning them out as soon as you see them can help, but there really isn’t any spray program that will help.  If you look closely on the stem beneath where you see browning the cankers will appear as sunken, dark brown or purplish patches on the bark, sometimes accompanied by resin (sap) flow.  This is fairly common on these plants which is one of the reasons I don’t recommend using them anymore. That doesn’t help you I know, so hopefully you can prune out and the damage will slow down.  

(September 2015)

I have two varieties of crab apple in my backyard. One of the trees is quite healthy but the other has had virtually of all of its leaves half chewed away. There no other visible signs of insects or borers. Will this affect the future growth? Is there anything that I should be looking for specifically?

Crabapples can be attacked by a number of diseases and insects, and some varieties are more resistant than others.  If the feeding damage occurred recently, don’t be concerned, since we are nearing the end of the growing season anyway.  If you have heavy damage early in the season and it occurs each year, that could weaken the tree and make it more susceptible to other problems.  Rake up the leaves this fall and start clean next spring.  You could also spray the tree with a dormant oil this fall after all the leaves fall off, if this is a common occurrence.  Dormant oil smothers out anything that is overwintering on the tree if you get thorough coverage, which will help again with a clean start next year.

(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.

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

(October 2008)

I have a sugar maple, ‘Autumn Blaze’ about five years old in my front yard facing the south. It is at least 10 to 15 feet tall. I recently noticed an area close to the bottom of the tree about 7 or 8 inches from the ground that is bleeding a black substance. Is this usual or should I be concerned?

One of two things can be happening. Maples are notorious for “bleeding” sap from any wound. If something wounded the tree such as a weed eater or lawn mower, this could simply be the case and is nothing to worry about. The other scenario could be wetwood or slime flux, which is caused by a bacteria. Gasses and liquid by-products of the bacteria cause the internal pressure of the sap to increase, forcing the liquid to ooze out any opening along the tree. It tends to have a sour or fermented smell to it and is quite attractive to insects. It can be dark in color or white and foamy. While it doesn’t signal imminent death, it does tell you the tree is stressed. Keep the tree as healthy as possible with regular watering. Try to use your garden hose to remove the sap from the trunk of the tree as the fermented sap can be damaging to the trunk of your tree if left there. This problem is usually more common during spring and summer.

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