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Root Lesion Nematodes

Root Lesion Nematodes. David Wichman’s samples In Oregon losses 8-60% (Semi-arid) Pratylenchus neglectus, P. thornei Species-specific resistance. Root Lesion Nematodes. Endoparasites. Root-lesion nematode damage to wheat. Cortical rot and pruning of lateral roots.

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Root Lesion Nematodes

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  1. Root Lesion Nematodes • David Wichman’s samples • In Oregon losses 8-60% (Semi-arid) • Pratylenchus neglectus, P. thornei • Species-specific resistance

  2. Root Lesion Nematodes Endoparasites

  3. Root-lesion nematode damage to wheat Cortical rot and pruning of lateral roots

  4. Annual No-till Spring Wheat in Soil Infested by P. thorneiat Pendleton Machete + aldicarb 27.8 bu/acre Machete control 14.3 bu/acre Photo courtesy of Richard Smiley

  5. The Spring Survey (2006): • 10 poorly performing fields in each of the 17 top wheat producing counties • ***Extension Agents*** • Information about cropping systems? Wendy Lewis

  6. Survey design • 148 fields in 2006 • 116 fields in 2007 • Alan Dyer and Wendy Johnson compared: Tillage type Cropping intensity Previous crop

  7. Whitehead Tray Method Soil moisture Pratylenchus spp. kg dry soil Counting

  8. Survey Results • 148 fields were examined in 17 counties • Pratylenchus neglectus found in 12 counties • P. thornei was never found (important!) • 14% of the fields had populations which exceeded damage thresholds (~2500 nematodes/kg of soil)

  9. Mean populations relative to cropping systems

  10. Ranking of Root Lesion Nematode Populations Resample in 2007

  11. Survey Results

  12. What Can You Do? • Avoid recrop (Tillage?) • Rotate to field peas? (Tailor et al. 2000)

  13. Future Work • Repeat survey • Develop resistance (Winter Wheat; Alan Dyer and Phil Bruckner) • Seed treatment

  14. Root Lesion Nematodes Damaging to Wheat Pratylenchus thornei Pratylenchus neglectus Courtesy of Jason Sheedy Oregon and Washington yield losses up to 36% in intolerant cultivars (Smiley et al. 2005) Oregon and Washington yield losses up to 70% in intolerant cultivars (Smiley et al. 2005)

  15. Root Lesion Nematode Biology Good Hosts Moderate Hosts Poor Hosts Field Pea Faba Bean Lentil Triticale Safflower Flax Wheat Canola Mustard Chickpea Barley Oat Durum Wide host range for P. neglectus Wild Oat (Vanstone 2002) Anhydrobiosis Migratory endoparasites

  16. Why didn’t we look before? Infestations mimic and are exacerbated by fungal infestations, nutrient deficiencies, and drought. Department of Agriculture and Food Western Australia Courtesy of CBARC Research Station, Pendelton, OR

  17. Root Lesion Nematode Management 1)Rotation non-host crop 2)Resistance varietal selection • no chemical control

  18. Survey design • 148 fields in 2006 • 116 fields in 2007 • Alan Dyer and Wendy Johnson compared: Tillage type Cropping intensity Previous crop

  19. 2006 Survey Results for Root Lesion Nematode 2500 P. neglectus kg dry soil

  20. 2006 Survey Results for Root Lesion Nematode

  21. 2007 Survey Results for Root Lesion Nematode 2500 P. neglectus kg dry soil

  22. 2007 Survey Results for Root Lesion Nematode

  23. Root Lesion Nematodes p=0.15 p=0.02

  24. Root Lesion Nematodes p=0.14 p=0.42

  25. Root Lesion Nematodes p=0.51 p=0.95

  26. Survey conclusions • P. neglectus was found at damaging levels in the north-central counties of Montana • Significantly higher populations of P. neglectus were found following a crop of winter wheat • No P. thornei was found…good for us!

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