Pythium Root Dysfunction of Creeping Bentgrass

Fig. 8. Individual patch of Pythium root dysfunction on a creeping bentgrass putting green. The profiles in the picture represent a diseased area and a non-diseased area. Note how the sand clings to the non-diseased roots and not the diseased roots.



Image from Plant Health Progress article:
Pythium Root Dysfunction of Creeping Bentgrass