The best way to prevent and control any diseases that may occur in your lawn is through continuous and persistent maintenance. This maintenance includes correct fertilization, irrigation (which includes watering and drainage), mowing height, appropriate maintenance tools that have been kept in good condition, placement in full sun, and use of disease resistant sod. Full sun is usually ideal for the health and proper growth of your lawn, but since this may not always be possible, it is important to remember that grass grown in shade will be more thin, weak and prone to stress. Along with exposure to sun, weather will also play a huge role in the outcome of your sod lawn. While we do have control over most factors regarding sod lawn maintenance, we don't have control over such weather conditions as temperature, drought or rain and the timing of it all. Since control over these factors are out of our hands, it is vital that we stay active and on top of the maintenance that we can control.
There are several different types of disease that can occur in your sod lawn. A disease will usually start out small with a few patches or spots throughout the lawn and then spread if left untreated. Sometimes a problem that seems more severe and sudden may appear, and that can often be caused by stress due to something besides disease such as improper fertilization, sudden extreme heat, poor drainage, or incorrect mowing. Correct drainage and irrigation is crucial to preventing many sod problems and can often be the root cause for various problems like discolored lawns. Diagnosis is key before taking the next step of treating the disease.
If the cause of the turf problem is a fungus, there are different types of fungicides that are meant to be used either preventively or curatively. Preventive fungicides work to activate a plant's natural defenses against infection. Curative fungicides can stop dead or diseased areas from getting bigger, but will not bring a dead patch back to life. It will take time for the grass to fill back in on its own, or it can be re-seeded. It can be helpful to keep a record of where the disease has occurred as fungus often occurs in the same areas year after year, so preventive fungicide can be accurately applied. Prevention is always best, which will include applying preventive fungicide, aerating, proper fertilization and irrigation maintenance.
The most common summer disease found in grasses like tall fescue is brown patch. It creates large, tan-colored lesions on the blade of grass and expands into circular patches up to several feet wide. Brown patch is most aggressive when there's a combination of high humidity and temperatures above 90 degrees, but can also become active when temperatures at night are above 60 degrees, thus being active through summer and well into September. Preventive fungicides are the best option for brown patch when applied in the spring or early summer. Large patch can be found in warm-season grasses like St. Augustine. Tan or red-brown lesions can be seen on the leaf sheath and expands into circular patches, oftentimes 12 feet wide. Large patch attacks when warm-season grasses are growing more slowly, during fall, winter and spring. It becomes active when temperatures drop below 60 degree, which is the ideal time to apply preventive fungicide.