Drought-distressed trees show signs of pine beetles, bacteria infestations

As I travel around the county, I see large numbers of dead trees.

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These trees are dying for many reasons. One is the prolonged drought. Drought-stressed trees are more likely to be attacked by insects, such as pine beetles.

I have two trees in my yard that have been killed by pine beetles. One shows the typical damage of the top turning brown. It seemed as if the tree turned brown overnight. The bark had fallen off the other tree. I didn't know it was dead until it broke off during the windstorm a couple of weeks back.

The strange part was the top of the second dead tree was still green.

The species of pine bark beetles that attacks pine trees in Georgia are the Southern pine beetle, the IPS engraver beetle and the black turpentine beetle. Of the pine beetles, the Southern pine beetle is the most devastating. It can kill a large number of trees across many acres in a short time. The black turpentine and the IPS engraver beetles are seen more by homeowners year in and year out. Of these two beetles, the IPS engraver beetle is the more destructive.

If you have trees that are infested with pine bark beetles, you need to take action quickly. If the tree is dead with the needles off, the beetles have left the tree, so you can take your time removing the tree.

If the tree is in the process of dying, it should be removed as soon as possible.

Trees that have an infestation of Southern pine beetles and IPS engraver beetles will start dying from the top down. Cutting the trees down will help stop the spread of the insects. When the tree is on the ground, you can spray the trunk with Onyx TM (bifenthrin) and remove it. If the tree is infested with black turpentine beetles, you can spray the trunk of the tree to a height of 12 feet to control them.

Another tree problem that I have received calls about this week is slime flux or wetwood. Slime flux is caused by bacteria. The bacteria can enter the tree through wounds or cracks in the bark. These wounds can be above or below ground.

It can take years for the bacteria numbers to build up to levels where damage can occur in the tree.

Once the bacteria builds up large numbers, they will start a fermentation process in the tree. This process will produce pressure and cause a liquid to ooze out.

Because this is a fermentation process, the liquid contains a type of alcohol. Alcohol flux is nearly colorless and acidic and gives off a pleasant fermentative odor.

The wetwood or slime flux will have a slimy appearance and texture. It has a foul, sour odor and will discolor the wood and bark of the trunk. This liquid will be under pressure when it comes out of the cracks in the bark. I have seen the pressure associated with slime flux be so great that you could hear a hissing sound as the gas and liquid escaped.

Slime flux can infect numerous species of hardwood trees in our area, including oaks, elms and yellow poplar. The tree that I have seen the most with slime flux is the oak. It can infect trees at different ages, but older, larger trees are infected most often.

Trees that have been infected with slime flux in severe cases can show some wilt in the top of the tree, and some branches might die. However, the most common problem is some disfigurement on the trunk. The wood in the area where the liquid seeps out will die. However, the tree will seal this area off and survive. Over time, a hollow area will appear at the site.

What can you do to protect the tree from slime flux? Keep the tree as healthy as possible by mulching around the tree, fertilizing it and watering if possible.

There are no pesticides or chemicals that can be used to control or prevent the infection.

Columbia County Extension Agent Charles Phillips can be reached at (706) 868-3413 or by e-mail at charlesp@uga.edu. The extension Web address is www.ugaextension.com/columbia