Turf diseases Or: what is that spot and what do I do about it? High similarity to TDNs (“those damn needlecasts”) The majority of turf problems are cultural problems

Thatch Layer Problematic if greater than ½ inch thick Caused by –Frequent, shallow irrigation –Excess fertilization –Under fertilization –Improper mowing Removing >1/3 leaf blade Increases susceptibility to pathogens and insects Not confusing, right?

Thatch Control Core aeration –Spring or Fall Proper fertilization – –1#N/1000ft 2 Memorial Day, Labor Day and Columbus Day Irrigate deeply and infrequently – 1-2 times, 1” total/week

Necrotic Ringspot Ophiophaerella korrae Mid-late summer root disease Affects Kentucky bluegrass Control –Resistant varieties –Good turf management –Fungicides

Fairy Rings Colonies of mushrooms growing outwardly in rings Inhibits grass growth within the band Stimulates grass growth on edge of band – decaying organic matter releases N Control –There isn’t any! –Can be masked by fertilization, frequent mowing –Core aeration

Leaf Spot and Melting Out Dreschlera sp. Cool Humid Periods Do not use excessive fertilizer Water deeply and infrequently Do not water in the evening Don’t mow too short Reduce shading Fungicides

Pink and Grey Snow Molds Multiple Fungi Favored by deep snowcover on non-frozen soil Tall canopy in late autumn Prevention/Control –Avoid excessive N –Mow in late autumn –Fungicide application in fall (different chemistry for each disease) Pink Snow Mold – Microdochium nivale Grey Snow Mold – Typhula sp.

Best Turf Management Practices for Disease Prevention Deep, infrequent waterings –1”/week total – Factor in rainfall –Never water in the evening Adequate but not excessive fertilization Plant appropriate grass for site –Bluegrass for sunny sites –Red fescue for shady sites Use mulching lawn mower Only remove 1/3 of leaf blade with each mowing Mowing height 2 ½ to 3 inches Core aeration Don’t apply a fungicide unless you know what the disease is