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Appendix A: Turf Pest Damage Monitoring Chart

This chart indicates when peak periods of damage are most likely to occur in the case of diseases and insects, and when seed will begin to germinate in the case of weeds. It is intended for use as a guide for monitoring pest activity and for pinpointing time periods when pest damage may occur. Please refer to the appropriate pest management sections of this guide for further information. This chart is not intended to indicate when applications of pesticides should be made, if at all.

Weeds J F M A M J J A S O N D Comments
General Weed Scouting Period                                                 Most weeds are large enough for easy identification.
Crabgrass and other Annual Grasses                                                 Period of peak germination.  Germination begins in spring when average soil temperature is 55°F for one week.
Annual Bluegrass                                                 Period of peak germination. May develop seed heads earlier in season if weather is favorable.
Yellow Nutsedge                                                 Sedges have triangular, solid stems, in contrast to the round, hollow stems of grasses.
Winter Annual Broadleaves                                                 Period of peak germination.
Summer Annual Broadleaves                                                 Period of peak germination.
Perennial Broadleaves                                                 Period of peak germination.


Insects J F M A M J J A S O N D Comments
White Grubs                                                 Turf appears to suffer drought stress. Skunks, raccoons, or birds may tear up the turf. Turf may pull up “carpet like.”
Ants                                                 Mounds in turf. Mound activity begins in mid-April to mid-May.
Billbugs                                                 Areas wilt and do not respond to watering. Sawdust-like material in thatch. Turf is easily tugged loose. Adults active in late May – mid June.
Chinch Bugs                                                 Wilted or browned areas, most severe in sunny or sandy areas.
Cutworms                                                 Burrows surrounded by brown patches, green frass may be present.
Annual Bluegrass (Hyperodes) Weevil                                                 Yellow patches begin at edges of turf areas. Damaged areas may appear water soaked. Usually two generations per year.
Sod Webworm                                                 Discrete browned areas which coalesce later. Most common in sunny areas. May cause damage in late spring.


Diseases that cause irregular damage J F M A M J J A S O N D Comments
Algae, Mosses                                                 Algae: irregularly thinning turf, soil surface with has green or black coating that is slimy to the touch. Mosses: irregularly thinning turf, soil surface with has a thick, silvery green mat.
Bentgrass Dead Spot                                                 Circular patches (1”-2”). Tan dead tissues with reddish-brown borders on young, sand-based bentgrass putting greens.
Brown Ring Patch (Waitea Patch)                                                 Yellow, irregular rings or arcs
Copper Spot                                                 Small, copper or salmon colored circular spots less than 3” in diameter.
Damping-Off, Seed Rot                                                 Poor germination and dying or dead young seedlings.
Gray Leaf Spot                                                 Gray to brown leaf spots with black margin and yellow halo. Can coalesce to irregular patterns and complete blight.
Leaf Smuts                                                 Gray to black streaks of black powdery spores on leaves. Usually in turf three or more years old.
Leaf Spots and Blights/Melting Out                                                 Oval or eye-shaped, dark bordered spots; dark specks (fruiting bodies) may be present in older diseased tissue.
Powdery Mildew                                                 White to powdery gray mold on leaf surfaces, often found in shade. No leaf spots present.
Red Thread/Pink Patch                                                 Pink-red, often gelatinous mycelium on leaves when moist.  Tiny pink cotton candy-like puffs of spores.
Rusts                                                 Irregular pattern of bright orange, yellow, reddish-brown pustules on the grass blades. Powdery orange spores.
Slime Molds                                                 Slimy, superficially whitish-gray to yellow fungus, turning powdery later.


Diseases that cause Circular damage J F M A M J J A S O N D Comments
Anthracnose (Crown/Basal Rot)                                                 Leaves yellow and wilt, tiny black spiny fungal hairs in tufts may be visible by hand lens.
Brown Patch                                                 1’-3’ patches of light brown grass. Gray to white (smoke ring) mycelium at edge of patch may be present in moist conditions.
Dollar Spot                                                 Straw-colored silver dollar-sized spots. Leaf bands with brown or reddish-brown borders. White mycelium when wet.
Downy Mildew (Yellow Tuft)                                                 Yellow patches or tufts < 1” across. Plants easily pulled from turf.
Fairy Ring                                                 Rings or arcs up to 15’ across often with outer ring of dark green grass. Mushrooms may be present in ring.
Microdochium Patch) (Pink Snow Mold)                                                 Small orange brown to tan spots. Under humid conditions white to pink mycelium at margins.
Necrotic Ring Spot                                                 Patches, rings, “frog eyes” approx. 6”- 8” across, enlarging later. Common in Kentucky bluegrass.
Pythium Blight                                                 Circular pattern with tan spots, lacking dark borders on the leaves. Leaves matted and slimy with dense white mycelium.
Pythium Root Dysfunction                                                 Circular or irregular patches slowly wilt due to affected roots. Often found following sand topdressing or on recently-constructed sand-based putting greens
Pythium Root Rot                                                 Turf wilted, killed, or rotted. Often in poorly drained areas.
Summer Patch                                                 Circular patches or rings of straw-colored grass 6”- 8” across. Center may be green. Common in annual bluegrass.
Take-All Patch                                                 Yellow turning reddish, then brown, and later sunken patches occur. Centers often invaded by weeds. Common in bentgrass.
Typhula Blight (Gray or Speckled Snow Mold)                                                 Matted grass covered with white-gray mycelium. Small reddish, brown, or yellow sclerotia present.
Yellow Patch (Cool Weather Brown Patch)                                                 Yellow to straw-colored grass often sunken in high cut areas.