Leaf Spot/Melting Out
Leaf spot/melting out are actually two different fungi, which attack the lawn at different times of the year. Both can be serious problems, especially as the diseases progress. It’s important to note that virtually every lawn has a little bit of leaf spot fungus and just seeing a few spots is generally no cause for alarm. It’s presence, however, should be taken as a warning to be sure proper cultural practices, such as mowing and watering, are adhered to as much as possible to prevent further development.
The two most common fungi in this family both exhibit the same symptoms at initial infection: Purplish colored lesions that develop tan centers as they expand. In severe cases, these lesions can expand to the entire leaf, giving it a wet, brown, and wilted appearance. It is common since it is spread by spores from lawnmowers, though the air, and anything else that it comes in contact with. One fungus attacks more in the spring during periods of heavy rain and humidity. The other tends to occur when temperatures are in the 80s and 90s, (typically summer). The summer fungus has more of a tendency to cause the “melting out,” or complete discoloration and wilt all the way down to the crown and roots. This is the most damaging stage. Prolonged melting out will usually result in permanent damage, or a very long period of recovery.
Conditions that favor the disease are humid, rainy weather. Excessive irrigation is a culprit in increased disease severity. Daily watering will usually cause greater disease problems.
Excessive nitrogen will only feed the diseases, so proper lawn feeding is essential for managing these fungi.
We can apply fungus controls for more serious cases. Bear in mind that fungus control applications are not a complete cure. They simply control it for a period of about 1 month.
