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

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

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

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

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

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)

Mean populations relative to cropping systems

Ranking of Root Lesion Nematode Populations Resample in 2007

Survey Results

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

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

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

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

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

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

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

Countyx P.neglectus RLN Incidence above damage threshold Chouteau384430% Fergus337570% Cascade325240% McCone144020% Hill88010% Pondera67910% Toole56510% Yellowstone3010% Glacier890% Phillips730% Roosevelt610% Valley50% Liberty00% Dawson00% Sheridan00% Richland00% Daniels00% 2006 Survey Results for Root Lesion Nematode 2500 P. neglectus kg dry soil

2006 Survey Results for Root Lesion Nematode

Countyx P.neglectus RLN Incidence above damage threshold Chouteau330640% Cascade267050% Fergus240020% McCone128510% Hill95310% Pondera81118% Toole237510% Glacier10020% Phillips00% Roosevelt240% Valley290% Liberty38510% Sheridan00% Daniels00% 2007 Survey Results for Root Lesion Nematode 2500 P. neglectus kg dry soil

2007 Survey Results for Root Lesion Nematode

Root Lesion Nematodes p=0.02 p=0.15

Root Lesion Nematodes p=0.14p=0.42

Root Lesion Nematodes p=0.51p=0.95

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!