Spring has finally arrived and it is accompanied by the usual compliment of infectious turf diseases. There should be no confusion between two “rhizoctonia” diseases. Yellow patch (aka cool season brown patch) prevails during early spring, when rainy weather is combined with cool nights. It also affects al turf species and the circular patches are most prominent on shorter mown turf (putting greens and surrounds). Brown ring patch (aka Waitea patch) visits later in the spring evening temperature increases. It is largely restricted to annual bluegrass.
Melting out on perennial ryegrass and Kentucky bluegrass is flourishing in some stands of taller mown turf (golf course roughs, municipal athletic fields and residential turf). Red thread and pink patch are bloom, and the solar spot pathogen has awakened and will make its presence known shortly (in my opinion).
Here in West Lafayette, soil temperature has increased to the point where the summer patch pathogen is emerging from dormancy. Our soil temperature monitor suggests that we are entering a period when applications of effective fungicides may limit infection.
For more information, including color images of these and other infectious diseases of turf, go to our Purdue Turf Program Website (www.agry.purdue.edu/turf/).
For more information on weather and turf diseases, go to http://btny.agriculture.purdue.edu/turfcast/