Planting for the 2019 small grains crop is set to begin. In anticipation of the next season here is an overview of what small grain problems that were diagnosed by the WSU Plant Pest Diagnostic Clinic between November 2017 and August 2018.
Root based issues are the most common problem sent in for diagnosis due to the ambiguous symptoms which can include yellowing, thinning, and reduced vigor. Plants suspected to be infected by viruses such as Soilborne Wheat Mosaic Virus, Wheat Streak Mosaic, and High Plains Virus are also frequently sent in for testing. Please note that negative results from these tests are not reflected in the table below. Abiotic issues that are frequently seen are weather-related, Physiological Leaf Spot, aluminum toxicity, and chemical damage such as potential herbicide damage which can only be confirmed by the use of a certified analytical lab as well as ‘burning’ from fertilizers.
Rotation legume crops frequently had root rot pathogens (Pythium, Fusarium, Rhizoctonia and Aphanomyces) and the recovery of Metalaxyl-resistant Pythium from both soil and plant tissue (http://smallgrains.wsu.edu/metalaxyl-resistant-pythium/). Due to this season’s prolonged wet, cool weather Ascochyta leaf spot complexes were recovered frequently from both chickpea and peas.
Plant samples can be sent in to the WSU Plant Pest Diagnostic Clinic year round. Soil tests are also available for select fungal pathogens. For more information on submitting a sample and specialized testing available please visit the Plant Path Diagnostics page.
Table: Small grain samples submitted to the WSU Plant Pest Diagnostic Clinic and the diagnosis associated. Abiotic issues are disorders such as nutrient issues, weather damage, soil characteristics, and variety traits. A diagnosis of abiotic stress is concluded based on the lack of evidence of pathogens or pests, information provided by the submitter, and symptomology of known abiotic issues.