Plant Pest Diagnostic Clinic Grains & Pulses Roundup

This week’s timely topic focuses on the maladies on grains and pulses samples that have come into the WSU-Pullman Plant Pest Diagnostic Clinic. Fifty-seven (57) samples came in between November 2016 and November 2017 with problems ranging from biotic pathogens and pests to soil, chemical, and environmental issues. Frequently what comes into the clinic for diagnosis are sampled with ambiguous symptoms, plants that show uncommon symptoms, and unfamiliar crops with unfamiliar symptoms. Root rots were a frequent issue this year given our cold and wet conditions that began during Fall 2016 planting and persisted through Spring 2017 during the planting of many pulse crops and spring wheats. Pink snow mold was also seen this year and submitted to the clinic for confirmation as it is not frequently observed in many of our counties. A number of soil samples were sent to the clinic for testing and were found to have Pythium that was resistant to the fungicide Metalaxyl-commonly used in the dryland region as a seed treatment. Environmental problems are continually observed and may be due to numerous things outside of the biotic realm including cold weather, nutrient disorders, chemical interactions, as well soil issues such as low pH, erosion, or compaction.

The clinic sees a snapshot of what happens in the field as weather conditions change and as new pathogen and pest issues emerge. The clinic is open year-round and can accept all types of agriculture crop as well as ornamental and private homeowner plant samples.

Plant Host Problem Number of samples
Wheat Suspect Herbicide Damage 2
Wheat Environmental (soil, nutrient, weather-based disorders) 4
Wheat Rhizoctonia Root Rot (Green-bridge complication) 1
Wheat Aluminum Toxicity 1
Wheat Cold Damage 3
Wheat Pink Snow Mold 1
Wheat Soilborne Wheat Mosaic Virus 1
Wheat Eyespot 2
Wheat Physiological Leaf spot 3
Wheat Fusarium Head Blight 1
Barley Hessian Fly, Lodging 1
Feed Barley No plant parasitic fungi present 1
Barley Root Rot Complex (Rhizoctonia and Pythium) 1
Barley Rhizoctonia Root Rot 1
Barley Environmental issue/Fusarium root rot/Thrips damage 1
Pea Aschochyta Blight 1
Pea Fusarium Root Rot 6
Pea Rhizoctonia Root Rot 2
Pea Seedling Root Rot Complex (Pythium, Rhizoctonia, and Fusarium) 1
Pea Aphanomyces Root Rot 1
Pea Low pH 1
Garbanzo Root Rot Complex (Pythium, Rhizoctonia, and Fusarium) 3
Garbanzo Seed Decay and Bulb mites 2
Garbanzo Metalaxyl Resistant Pythium 1
Garbanzo Abiotic Stress 1
Garbanzo Environmental Stress (pH) 1
Lentil Environmental Stress 2
Lentil Rhizoctonia Root Rot 1
Lentil Root Rot Complex 2
Lentil Fusarium Root Rot 1
Soil Metalaxyl Resistant Pythium 7
Total 57
Table 1: Wheat and pulse crops that were submitted to the clinic for diagnosis between November 2016 and November 2017.

Washington State University