Justin Hand

Justin Hand, Tift County ANR/4H agent with UGA Extension.

Recently, I was sitting on my porch reading and listening to the rain. It was a nice afternoon, until I heard a clicking and hissing sound followed by my dogs barking. I realized my irrigation system had turned on and, like the rain, began pouring water into my yard.

Having extra water is not necessarily bad, however, with the excess rain we have had in South Georgia lately, it could become a problem.

Root Rot is a common plant disease in Georgia caused by excess water in the soil. We have seen root rot on a full spectrum of plants including roses, marigolds, verbenas, hollies, box woods, azaleas and rhododendrons.

The problem with root rot is that the symptoms are often confusing. People see plants that are wilted and yellowing, with stunted growth and they naturally think the problem is lack of water - so they water more! Unfortunately, the causes of root rot - Pythium and Rhizoctonia - are both very aggressive pathogens that thrive in wet soil.

If you do have root rot disease, it's primarily a water problem. Chances are the plant has been watered too much, or the soil drainage is poor, or both. Healthy above ground growth depends on an extensive, well-developed, deep root system. The weaker and less extensive the root system, the more susceptible the plant is to stress and disease.

In extreme cases, the root system may be so weak that the plant will die even during favorable summer weather conditions. Several factors can contribute to poor root development, including nematodes, compacted soils, pH or nutrition problems and poor watering techniques.

If you are concerned about nutrition problems, bring your soil to the Extension office to have a soil test done to determine what type and how much of a fertilizer to add, as well as pH recommendations.

One good watering each week is enough for most plants. Avoid light watering that gets only the top layer of the soil wet but doesn't penetrate the 3 to 4 inches’ plants really need. Often people overwater simply out of habit or because the top layer of soil is dry.

It's important to check the soil from time to time to see how well it is draining and whether plants are getting enough or too much moisture. Dig about 6 inches down to see how much moisture the soil contains. Don't dig into the root systems of plants, but rather dig around them. But, make sure you get down below the root zone - about 6 inches, in most cases. If it's dry and powdery that far down, it needs to be watered. It should be damp. Well-watered soil will stick together when it's pressed into a ball.

Another key to preventing root rot is to carefully check new plants before introducing them to the garden. Contaminated soil is another way that pathogens or diseases can be introduced. Take one or two plants out of a flat of bedding plants and take a close look at the roots. Roots should be white or silvery. If they're brownish, soft or sparse, then the plant is probably infected with a root rot-causing pathogen. Don't introduce sick plants to the growing site.

If root rot is diagnosed, there are fungicides on the market that, if wisely chosen, can reduce or alleviate the problem. However, the best thing to do is to correct the real problem and avoid overwatering. After all, the root of the problem is in the roots.

If you have questions about plant diseases, contact the Tift County Extension Office at 229-391-7980 or uge4277@uga.edu.

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