Managing Turfgrass Diseases
Turfgrass Disease Development
There are several diseases that could potentially infect turf in northern Illinois. The general environmental conditions occurring on the turf, how the turf is managed, and weather conditions all impact turfgrass disease development. Turf diseases need favorable conditions to develop. The best defense against diseases is to maintain healthy turf through sound cultural practices, avoiding favorable conditions for disease. Disease outbreaks often occur when turfgrasses are not managed properly or are under extreme stress, such as from poor soil conditions or perhaps weather conditions (see Table 1).
Table 1: Disease Requirements & Turf Disease Management
|Condition||Management Practices to Avoid Disease|
|Susceptible Grass Plant||Resistant species/cultivars
Use of mixtures/blends
(Fungi for most diseases)
|Fungicides (temporary protection)
Can never eliminate all causal agents
|Proper Environment for
Causal Agent to Develop
Proper turf management practices
(watering, fertilizing, etc.)
Fungicides are rarely suggested for use on home lawns. Instead, follow sound lawn care practices to prevent serious problems. When a disease outbreak occurs, follow renovation procedures and adjust future lawn care practices as needed to prevent the disease from returning.
Some Common Turfgrass Disease Scenarios
|Low Fertiliy, Moisture, Turf Vigor|
|Dollar Spot||Small blighted areas.
Hourglass lesion girdles blade. Colored band on lesion edge.
|Red Thread||Pink to red masses on leaf blades.
Threadlike appendages from leaf tips.
|Rust||Orange pustules on leaf blades.
Orange powder from affected grass.
|Excess Nitrogen Fertility, Thatch|
|Leafspot/Melting Out||Brown to purple lesions (spots) on blades.
Irregular dying areas of grass.
Lesions on grass in margins of dead areas.
|Snowmold||Irregular matted areas.
"Moldy" appearance in spring.
|Heavy Clay Soil, Soil Compaction, Thatch, Poor Establishment|
Necrotic Ring Spot
|Circular/crescent shaped patches.
Irregular dead areas.
Patches in newer sodded lawns.
Finally, powdery mildew is a common turfgrass disease in shade areas. Powdery mildew is easy to identify; as grass appears whitish in color. Powdery mildew develops primarily on Kentucky bluegrass in the shade. Choose shade tolerant grasses and follow shade lawn management practices.
Written by Bruce Spangenberg, former Extension Educator, Horticulture. University of Illinois Extension.