2023 Plant Diagnostic Clinic Wrap-up

Soilborne Wheat Mosaic Virus.

Overall, disease-associated problems were few in the 2023 crop year and likely due to the relatively dry fall conditions in 2022 and cool, dry 2023 spring. Stripe rust was predicted to be average to above average in January, but spring weather delayed onset of rust until late in the growing season resulting in less rust damage than anticipated.

Planning for the 2024 small grains crop is well underway. In anticipation of the next season, here is an overview of what small grains problems that were diagnosed in 2023 by the WSU Plant Pest Diagnostic Clinic.

Abiotic issues that were frequently seen were: weather-related, Physiological Leaf Spot, and chemical damage such as potential herbicide damage, which can only be confirmed using a certified analytical lab, as well as ‘burning’ from fertilizers as well as too deep planting.

Diseases that were observed in the lab included mostly root-based and virus issues. Most of the samples received this year were soft white winter wheat, although a few barley samples were submitted (environmental stresses) as well.

Soilborne Wheat Mosaic Virus was observed in a new location north of Highway 2. This follows on the detection of another northern location in 2022 outside the area where this disease was known to occur in Washington. Fortunately, resistant varieties are available to address this problem. Read more about the new SBWMV finding.

Field symptoms of yellowing and mosaic of wheat infected with Soilborne Wheat Mosaic Virus.
Field symptoms of yellowing and mosaic of wheat infected with Soilborne Wheat Mosaic Virus.

Rhizoctonia Root Rot has been observed nearly every year. It is being seen more outside of the Walla Walla area and in the Palouse in spots.

Barley Yellow Dwarf Virus was observed in a few wheat samples that were submitted. The wheat was also under multiple environmental stressors (weather and water).

Plant samples can be sent into the WSU Plant Pest Diagnostic Clinic year-round. Soil tests are also available for select fungal pathogens. For more information about submitting a sample and specialized testing available, please visit the Plant Pest Diagnostic Clinic’s website.

The 2024 crop year is shaping up differently than 2023, with early moisture in August and September that has resulted in abundant volunteer and planting/emergence of winter wheat occurring earlier than the past couple of years. These conditions are more conducive for fall establishment of stripe rust, eyespot, and Cephalosporium stripe than we’ve experienced the past several years. In addition, wheat streak mosaic virus can build-up in volunteer wheat, which should be destroyed before planting.

Cassandra Bates.

For questions or comments, contact Cassandra Bates via email at cass.bates@wsu.edu or contact the Plant Pest Diagnostic Clinic directly via email at plant.clinic@wsu.edu or phone at 509-335-3292.