Description

One problematic disease in lentils (Lens culinaris) is root rot, caused by a complex of soilborne pathogens found in the genera, Fusarium, Pythium, Rhizoctonia, and Aphanomyces (Gossen et al., 2016). Nested within the complex are closely related species that can coexist and have synergistic effects on the severity of root rot. The breadth of taxonomic diversity of causal pathogens and reliance on visual-based symptoms makes it challenging to identify the primary drivers of root rot disease in North Dakota. Without pathogen identification, producers rely on broad-based management, which may vary in success across root rot pathogens.

Utilizing molecular diagnostics can help disentangle the complexity of root rot disease and improve management research in several ways. First, molecular diagnostics can confirm the causal pathogen in symptomatic plants as well as provide a method to identify asymptomatic plants that are missed when relying on visual-based cues for disease. Second, molecular diagnostics can assess disease potential by directly testing environmental samples (soil and residue) prior to planting. Knowing what pathogens are present and their relative densities in the field can help producers become proactive instead of reactive with root rot disease management. Third, molecular diagnostics from testing laboratories can support extension scientists, limited by time and resources, with ongoing research that would benefit from evaluating pathogen densities in experimental field plots. Together with visual-based observations, molecular tools can advance field research and identify the major root rot pathogens impacting North Dakota’s lentil production area.

NAGC has optimized three diagnostic assays that quantify nine root rot pathogens in pulse crops and environmental samples with special attention to lentil research. Specifically, NAGC’s molecular assays detect, differentiate, and quantify the most abundant and relevant pathogens for lentil growers:

PRR1.1-Q: Aphanomyces euteiches, Fusarium avenaceum, and Fusarium acuminatum

PRR2-Q: Pythium spp., Phytophthora medicaginis, and Rhizoctonia solani

PRR3-Q: Fusarium redolens, Fusarium solani, and Fusarium oxysporum

This project was funded by the North Dakota Department of Agriculture Specialty Crop Block Grant.

References

Gossen, B. D., Conner, R. L., Chang, K.-F., Pasche, J. S., McLaren, D. L., Henriquez, M. A., Chatterton, S. & Hwang, S.-F. 2016. Identifying and Managing Root Rot of Pulses on the Northern Great Plains. Plant Disease, 100, 1965-1978.