Turf diseasesOr: 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/1000ft2 Memorial

Day, Labor Day and Columbus Day

• Irrigate deeply and infrequently – 1-2 times, 1” total/week

Necrotic RingspotOphiophaerella 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 OutDreschlera 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 MoldsMultiple 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