17. How do you choose a fungicide?Heritage (0.2 oz, 28 day) Eagle (1.2 oz, 14 day)
18. Fungicide SelectionReferences• Product Labels• Pest Control for Professional Turf Managers• TurfFiles Disease Profiles• TurfFiles Fungicide Selection Tool
19. Diseases of Centipedegrass • large patch • dollar spot • fairy ring
20. Diseases of St. Augustinegrass • large patch • gray leaf spot • take-all root rot
21. Diseases of Zoysiagrass • large patch • dollar spot • rust • Curvularia blight • spring dead spot • fairy ring
22. Though caused by the same fungus, brown patch and largepatch are very different diseases.
23. Though caused by the same fungus, brown patch and largepatch are very different diseases.
24. Large patch causes rotting of the leaf sheaths beginning in late symmer, which leads to foliar dieback in fall or spring.
25. Large patch is the most severe disease of zoysiagrass
26. Centipedegrass is most susceptible to large patch
27. Large patch rarely causes long-term damage to bermudagrass.
28. Conditions favoring large patch development• infection occurs when soil temperatures are below 70°F• saturated thatch/soil• excessive nitrogen during periods of slow growth• excessive thatch accumulation• low mowing heights
29. What is wrong with this picture?
30. Large patch is active when soil temperatures are below 70ºF
31. Controlling Large Patch with Fungicides• preventative applications most effective• initiate in fall when soil temperatures decline below 70°F• one properly timed application will provide good control in most landscape situations• in severe cases, repeat applications on 4 to 6 week intervals may be necessary• curative applications help to reduce further spread, but recovery will be slow
32. provide outstanding control ofQoI Fungicides Rhizoctonia diseases
34. Large patch control in ‘Meyer’ zoysiagrass Untreated Banner Maxx (4 fl oz) Heritage (0.4 oz) Bayleton (1 oz) Prostar (2.2 oz) 0 5 10 15 20 25 30 35 Large Patch Incidence (%)Lawrence, KSTreatments applied Oct 8Data collected Apr 24
35. Untreated Bayleton (2 oz)
36. Spring dead spot symptoms appear in spring as thebermudagrass resumes growth.
37. Spring Dead Spot Attacks All Below-Ground TissuesInjury to roots, stolons, and rhizomes renders the bermudagrassmore prone to winter injury.
38. Conditions Favoring Spring Dead Spot Development • any factor that restricts root growth • soil compaction • excessive thatch • wet soils • any factor that reduces winter hardiness • excessive nitrogen in fall • potassium deficiency • wet soils
39. Regular aerification reduces spring dead spot development
40. Recovery from spring dead spot is very slow....
41. Speeding Spring Dead Spot Recovery• avoid use of DNA herbicides in spring - dithiopyr (Dimension) - pendimethalin (Pendulum)• aerify or spike affected areas every two weeks• apply light and frequent irrigation• apply 1 lb N per 1000 per month from May to Sept
42. Spring dead spot can be controlled with fungicides
43. Rubigan (6 + 6 fl oz) Untreated Control
44. Keys to Successful Control of SDS• commit to implementing program for at least 3 years• map affected areas in spring for treatment• select an effective product• apply preventatively in fall when soil temperatures are between 60˚F and 80˚F• water-in immediately with 1/8” to 1/4” of irrigation
45. Two species of Ophiosphaerella cause spring dead spot
46. Nitrogen Source Influences Spring Dead Spot Dvelopment Sulfur Coated Urea Calcium Nitrate Urea Ammonium Sulfate Spring Dead Spot Index (diameter*incidence) 90 25 a O. herpotricha a O. korrae a 75 a 20 a 60 a 15 45 a a a b a a 10 30 ab b ab 5 15 b a b a a c a b b 0 0 2007 2008 2009 2007 2008 2009Nitrogen treatments applied monthy from May through August in 2006, 2007, and 20081 lb N per 1000 ft2 per application; 4 lbs N per 1000 ft2 per year
48. Ammonium Sulfate
49. Calcium Nitrate
50. Gray leaf spot of St. Augustinegrass.
51. Gray leaf spot is most severe in St. Augustinegrass that isgrowing slowly or is mowed infrequently.
53. Conditions Favoring Gray Leaf Spot• 75ºF to 95ºF• Extended periods of leaf wetness• Most severe in newly established plantings• High mowing heights and/or infrequent mowing• Slowly growing turf• Turf stressed by nutrient deficiency, drought, or traffic