Many Boston Area lawns have brown or yellow splotches and circles on them, after a week of mostly wet weather including rain days and cool nights in the upper 40’s and low 50’s. The suspects? Many customers rightly say the grass looks stressed or burned but they know water is not the issue. Other customers have said they suspects insects, but grubs probably haven’t caused that kind of damage yet, more toward July and August. In most cases we have inspected, the cause is fungus. There are many lawns with brown patch or yellow patch and red thread. Against intuition, these areas affected tend to be the sunnier parts of the lawn. The reason, according to Craig Heffron from John Deere Landscapes, the temperature in these areas is high enough to incubate the fungus. Cultural controls are critical for fungi, illustrating the importance of balanced lawn fertility, and proper maintenance practices.