Diseases of Bentgrass, Ultradwarf Bermuda and more. Alan Windham Plant Pathology University of Tennessee

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1 Diseases of Bentgrass, Ultradwarf Bermuda and more Alan Windham Plant Pathology University of Tennessee

2 Abiotic Problems

3 Diagnosing Abiotic Problems Often associated with stress related to weather phenomenon May be related to cultural problems May be related to fertilizer or pesticide inputs

4 Abiotic (non-living cause of disease) What gives you a clue?

abiotic cause Nothing indicates that this is a

5 Signs or Symptoms Lack of signs or symptoms that would indicate a pathological problem point to an abiotic cause Nothing indicates that this is a disease No mycelium No fungal fruiting bodies No spores

6 Roots are healthy; foliage is bleached but no sign of fungal infection

7 Bentgrass roots stained with acid fuchsin; ; no sign of any root pathogens

8 Root tip is composed of: Root cap-protects root as it moves through soil Meristematic region where cell division takes place Zone of elongation where cells grow to their normal size

9 Root Cap Meristematic Region (zone of cell division) Bentgrass Root Tip Zone of elongation

10 Anatomy of a root Region of elongation Meristematic region Root Cap

11 Value of core aerification Root growth most abundant in aerification channel where O 2 level is highest.

12 Profile Problems Zone of high organic matter; often anaerobic; smells like a sewer; will not support root growth

13 Severe layering problem Black layer developing

14 Washed portion of plug; organic mat holds water and thus heat

15 Multiple black layers

16 Pathological root problems Pythium oospores stained with acid fuschin A pythium infection in the meristematic region can slow or stop root growth

17 Discolored roots + fungal structures = trouble Bentgrass root with a discolored center (stele) due to ETRI fungal infection

18 Root galls may = Root knot nematode A nematode infestation usually impairs root function and may lead to secondary problems from infections from other pathogens. Galls on bentgrass roots caused by root knot nematode

19 Root knot nematodes Root knot nema in root gall Female root knot

20 Root knot nematode eggs Female root knot nematodes may produce eggs in egg masses

21 Anthracnose Caused by Colletotrichum cereale Grass is thinned Fungus visible on foliage, crown of plant Bentgrass

22 Anthracnose Setae- hairlike structures associated with fruiting bodies (acervulii)

23 Anthracnose Crescent shaped spores

24 Anthracnose Appresoria infection structures, visible in crown and root tissue

25 Anthracnose Infection mats Infection mats in leaf sheath

26 Rhizoctonia Diseases Brown patch cool season grasses Large patch zoysia and bermuda Yellow patch bentgrass Waitea patch- bentgrass, Poa annua

27 Brown Patch Warm weather disease of a cool season grass

28 Heritage applied at 28 day intervals; UT Plant Science Farm Brown patch control Untreated Heritage

29 Large patch This Rhizoctonia disease is active at green up on zoysia and bermuda

30 Yellow Patch White mycelium forms smoke ring Creeping bentgrass December 2007

31 Rhizoctonia cerealis Right angle branching

32 Waitea patch Described by Dr. Frank Wong, UC Riverside, on Poa annua

33 Southern Blight

34 Southern blight causal fungus Sclerotium rolfsii Occurs during very hot weather; fungus produces abundant white mycelium

35 Sclerotium rolfsii Fungus produces spherical structures called sclerotia (pl)

36 Southern blight-tall fescue

37 Pythium Diseases creeping bentgrass Poor color from pythium root decline Pythium blight- fungus has followed movement of water on green

38 Pythium blight of an ultradwarf bermuda? TifEagle

39 Pythium on Tifeagle Abundant white mycelium; also water soaked foliage

40 Pythium reproductive structuresoogonia

41 Rapid Blight Caused by a primitive fungus- Labyrinthula. Salinity usually is a problem when rapid blight shows up. Could be found on courses that use treated wastewater for irrigation source.

42 Labyrinthula cells dispersed when diseased tissue was macerated

Managing Turfgrass Diseases

Page 1 of 6 Managing Turfgrass Diseases Department of Crop and Soil Sciences - Cooperative Extension Turfgrass Diseases Anthracnose Foliar Blight and Basal Rot, Colletotrichum graminicola Anthracnose can