Localized Dry Spots on Turfgrass

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Localized Dry Spots on Turfgrass
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What is a Localized Dry Spot?

• Localized Dry Spots hot spots, isolated dry
  spots
• Soils which have become water repellent
• Most common in high sand situations like USGA
  greens and similarly constructed areas
• LDS may also occur on mineral soils

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From http//www.agcsa.com.au/atm/articles/vol46/d
ryspot.htm
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Coated vs. non-coated soil
From http//www.agcsa.com.au/atm/articles/vol46/d
ryspot.htm
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What is a Localized Dry Spot?

• Causes
• microbial decomposition of organic substances
  (peat, roots, shoots)
• Fungal activity and frequent wet-to-dry cycles,
• can produce a wax-like and water repellent
  coating on sand particles. (Leinauer 2002)

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LDS incitants

• Hydrophobic materials may include
• accumulated plant-derived organic matter (thatch,
  decomposing roots, decomposing plant tissues, and
  root exudates)
• plant-derived waxes and organic acids
• fungal hyphae
• microbial organic acids and polysaccharides
  (Kostka 2000)

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LDS

• Studies of two wetting agents Primer 604 and
  Midorich to combat LDS were performed recently
• Primer 604 significantly improved water retention
  in soils with LDS
• Midorich did not significantly improve water
  retention in soils with LDS
• http//www.uoguelph.ca/GTI/99anrep/99r_4.pdf
• http//www.paceturf.org/index.php

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LDS

• It was suggested by the researchers that
  increased water retention following treatment
  with wetting agents was due to
• 1) Greater retention of fine soil particles in
  the root zone
• 2) A hydrophilic coating on the soil particle
  created by the wetting agent

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Wetting agent studies

• http//www.gcsaa.org/GCM/2005/aug05/PDFs/071-083_W
  ettingAgent.pdf
• http//www.eifg.org/focus/research/wetting_agents/
  index.asp

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LDS

• In another study researchers looked at the
  wetting agents Respond and Primer in combination
  with the fungicides Heritage and Prostar.
• The fungus Agrocybe pediades (as well as other
  basidiomycetes) has been found in association
  with LDS and fairy ring

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LDS

• Heritage Respond and Prostar Respond provided
  the best management of LDS and fairy ring (Type B
  and C)
• Type B fairy rings generally cause little damage
  due to hydrophobic conditions while type C fairy
  rings cause extensive damage
• Respond or Primer both managed LDS and type C
  fairy ring when combined with fungicides in this
  study

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Type C fairy ring- from http//www.interactiveturf
.com/pest/20020715_Fairy_ring_LDS.htmPhoto5
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From http//www.interactiveturf.com/pest/20020715
_Fairy_ring_LDS.htmPhoto5
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References

• Kostka, S.J. 2000. Amelioration of water
  repellency in highly managed soils and
  enhancement of turfgrass performance through the
  systematic application of surfactants. Journal of
  Hydrology 231-232359-368.
• Leinauer, B. 2002. Wetting agents and their
  impact on water retention of turfgrass root
  zones. Australian Turfgrass Management Volume
  4.1.