1 / 25

The Environment of Turfgrass Pathogens

The Environment of Turfgrass Pathogens. HOST PLANT. DISEASE. PATHOGEN. ENVIRONMENT. Pathogen Life History. dispersal. infection. 2 O cycles. colonization. survival. reproduction. environment. host. host. host. environment. environment. host. environment. host.

reece-horton
Download Presentation

The Environment of Turfgrass Pathogens

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The Environment of Turfgrass Pathogens

  2. HOST PLANT DISEASE PATHOGEN ENVIRONMENT

  3. Pathogen Life History dispersal infection 2O cycles colonization survival reproduction

  4. environment host host host environment environment host environment host Pathogen Life History dispersal infection 2O cycles colonization survival reproduction

  5. GRASS GRASS PATHOGENS ENVIRONMENT LOW DISEASE POTENTIAL HIGH DISEASE POTENTIAL

  6. GRASS GRASS PATHOGENS ENVIRONMENT LOW DISEASE POTENTIAL HIGH DISEASE POTENTIAL SEASON WEATHER LANDSCAPE

  7. LANDSCAPE EFFECTS Highly exposed

  8. LANDSCAPE EFFECTS Low air movement Shading

  9. In natural ecosystems, disease is common, but epidemics are rare Disease across a population = epidemic Disease on individual plant

  10. Turfgrass is prone to epidemics • Monoculture • High plant density Leaf to leaf hyphal growth

  11. CANOPY Two parts of the environment ROOT ZONE

  12. Above-ground environment for pathogens Positive factors Nutrients Sugars and amino acids from plant (wounds), air (pollen), insects (honeydew)

  13. Above-ground environment for pathogens Positive factors • Moisture • Atmospheric (humidity) • Supports fungal growth (>95%RH) • Prevents dessication • Free moisture (leaf wetness) • Needed for spore germination • Bacterial growth and mobility • Nutrient transport • Sources: dew, guttation, rain

  14. Dew

  15. Guttation

  16. Above-ground environment for pathogens Negative factors Ultraviolet light • Lethal and mutagenic • Air movement (wind) • Causes drying of leaf surface • Some beneficial effects for • pathogen, however: • - Evaporative cooling • - Pathogen dispersal

  17. Effects of some cultural practices on canopy environment

  18. Mowing provides wounds • Source of nutrients • Point of pathogen penetration

  19. Irrigation • Lengthens leaf wetness period • Increases canopy humidity • Cools leaf surface

  20. By design, turf grass is planted in high • densities. This results in: • - Reduced ultraviolet penetration • - Reduced leaf temperatures • - Reduced air movement through canopy • - Increased canopy humidity • - Increased leaf wetness period

  21. Below-ground environment for pathogens • Pathogens typically located within top 8 inches of soil profile • Most are stationary • Nutrients and host plant must come to pathogen • Pathogens remain dormant unless provided with nutrients

  22. 3 Two parts of the environment CANOPY THATCH ROOT ZONE

  23. 3 Two parts of the environment CANOPY Little to no UV Leaf wetness nearly continuous Very high humidity THATCH ROOT ZONE

  24. 3 Two parts of the environment CANOPY “psuedo-root zone” THATCH Growth and infection by root pathogens! ROOT ZONE

  25. Summary • Disease epidemics are uncommon in natural stands of grass • Cultural practices cause turf grass to be prone to epidemics • Cultural practices modify the environment to be more consistently favorable to pathogen growth and infection

More Related