 Pest Crew
Diseases - Dr. Stephen Vann
I have a row of 30 evergreen trees along my property line that I planted about five years ago to create a screen between my house and my next door neighbor. The man at the nursery said they were called Leyland cypress. They have done very good for the sunny location that they are in. They have tolerated the hot summers and cold winters we have had here. I think they are about 20 feet tall and are in a lower area in my backyard that tends to stay wet for awhile, especially following a heavy downpour. My backyard slopes down toward these trees. I have not fertilized the trees, since they seem to be doing well, at least up until last year. Last spring, I noticed two or three branches on a few trees started to get brown. It seemed to start toward the end of the branch and progress downward toward the main stem. The branches started off as a tan or straw color, then change to a dark brown. It is getting worse. Now, most of the trees have a few dying branches. Is this a disease or what? And, how do I fix it? I don’t want to loose these trees. (Janet from Hot Springs)
From what you are describing, this sounds like an infectious disease that has been quite common on this tree since it became popular in both residential and commercial landscapes over the last several years. This disease is often referred to as “branch canker” or “branch dieback”. It is caused by a fungus that infects the branches and causes them to die starting at the branch tips. The fungus is often spread from tree to tree by wind and splashing water from rainfall or overhead irrigation. The fungus produces microscopic spores that enable it to spread easily. This disease has been a real headache from people that have this tree in their landscape. The fungus seems to be quite specific to this tree. Unfortunately, if the tree has lots of dying branches in it, it may not be able to be saved. It is a progressive disease that can move rapidly, especially during wet weather. The best way to manage this disease is to remove the dead branch portions by pruning as soon as you see them. The earlier you catch it and remove that portion, the better your success rate is. On affected branches, locate the area where the brown stem meets the green, “healthy” portion, then go back into the green area six or so inches to make your cut. Perform pruning activities only when the branches are dry. You might consider sanitizing your pruners with rubbing alcohol after each cut. Burn or otherwise destroy the pruned branches. Pesticides (fungicides) have not been shown to be effective. If you are planting Leyland cypress for the first time, be sure to leave plenty of space between them and other plants to allow good air circulation to keep the branches dry as possible. See
Extension Fact Sheet 7536 for additional information.
I have two small peach trees in my yard that have started to develop a strange problem over the last few years on the leaves. Every spring the leaves come out just fine, but soon afterwards, start getting red and wrinkled. Many of the leaves are folded and are warty looking. Later on, they get this gray color and powdery look. I have noticed that the leaves drop early in the summer. The fruit looks OK, but there seems to be less of them since I noticed this leaf problem. Any suggestions? (Stan in Nashville)
Stan, this is a disease that infects peaches, apricots and nectarines called “leaf curl” It is caused by a fungus that is spread by wind and splashing water. The fungus infects the buds just as they start to swell in the spring. The disease caused the leaves to look “weird” and is sometimes confused with insect damage. Early leaf drop is the primary problem, but this can lead to fewer fruit as you describe. The disease can usually be managed by a single spray of a fungicide, but it must be sprayed on BEFORE the buds start to swell. If you miss this time, your spray will be ineffective. Most folks spray during the dormant season just before buds start to swell in the spring. Fungicides that contain chlorothalonil or copper are used. Bordeaux mixture is also effective. These materials act to protect the new leaves and are readily available from many garden centers. You will need a good sprayer capable of covering the entire tree. This, in conjunction with the correct time is very important for disease management. Be sure to read the chemical label carefully before applying. For additional information and specific spray recommendations, contact your local
county Extension office.
I woke up one morning in August to notice a bunch of gray-green colored
mushrooms growing in my bermudagrass lawn. These big things seemed to just
appear in my yard overnight and after looking a bit closer, I noticed that they
were growing either in a big circle or an arc. They were scattered over a big
area in my back yard. The grass does not appear to be dying. Where did these
things come from and will they hurt my grass? (Steve in Little Rock).
These mushrooms that you saw are probably the result of a lawn problem
called "Fairy Ring". Many types of fungal microorganisms can cause fairy
ring. These microorganisms live in the thatch layer and soil and send up a
mushroom when they reach a certain stage of growth. These mushrooms often
appear during the summer or fall and produce spores that enable the fungus
to spread to other locations, usually by wind or splashing water. The spores
are released from the mushroom and sometimes appear as a "brown powder".
Some of these mushrooms are poisonous. The microorganisms that cause are
often associated with decaying wood that is buried in the soil. This wood
may be an old tree stump or even old building materials that were buried in
the soil. Fairy rings are mostly cosmetic in the home lawn, but can have a
significant impact on the golf course. Homeowners should just mow these
mushrooms off or physically remove them as soon as they are seen, since they
can be poisonous to pets or children. For additional information refer to
Extension Fact Sheet FSA7539.
My Beefsteak tomatoes have developed a dark brown to black rotted area on the
fruit. This dark area looks like it starts on the bottoms of most of the
tomatoes on the plants. The leaves look fine; it is just the tomato itself that
looks bad. The plants are getting 6-8 hours of sunlight and are growing in a
garden spot that I have had for the past 5 years. I water early in the morning
to keep the leaves dry. Every one of my eight plants is doing this. Is this a
disease? (Susie in Fayetteville).
This dark area that has developed on the bottoms of the fruit sounds very
much like a disorder called blossom end rot (BER). This is not an infectious
plant disease, but rather a nutrient problem- probably a lack of calcium in
the soil. This can be corrected by adding something like lime to the soil to
correct the pH. Ideally, lime should be added before planting and based on a
recent soil test. Sometimes BER is associated with extreme moisture
fluctuations in the soil in conjunction with the calcium deficiency. Calcium
can also be added after the plants are producing. Several calcium products
are available at many garden centers that can be sprayed on the plants and
are absorbed to correct the imbalance. It is always a good idea to have a
soil test done before planting your tomatoes and other vegetables, making
sure that the pH is within an optimum range- usually around 6.5 to 7.0.
Contact your local
county Extension office to see about having your soil
tested.
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