Role of crop fertility and seed treatments in managing fusarium root rot of lentil (Lens culinaris Medikus) in the northern Great Plains

Abstract

Lentil is a relatively new but economically important crop for the state of Montana, along with surrounding states in the northern Great Plains. Comparatively little is known about the basic fertility of lentil, and importance of inoculant type on lentil. Additionally, the rise of pulse crop acres in the northern Great Plains, has given rise to root rot pathogens, such as Fusarium root rot. Fusarium root rot of pulses, has a wide host range, limiting the efficacy of rotation in its management. This research is comprised of two main studies. Field trials occurred at sites in Bozeman, Havre, Moccasin, and Sidney in 2019 and 2020. The objective of chapter two was to evaluate the effect of rhizobial inoculant formulations (granular vs. seed-coat/peat-powder) and nutrient additions (potassium, sulfur, and a micronutrient fertilizer), on lentil establishment, growth, seed protein, and yield. For chapter two, in six of eight site-years there was no yield difference between inoculant types. Applications of sulfur (S) fertilizer increased yield at three of eight site-years by an average of 303 kg ha-1 (17%) compared to treatments without S. Results from this study further suggest the importance of S fertilization for lentil. The objective for chapter three was to evaluate seed treatments' ability to control Fusarium root rot on lentil establishment, growth, disease severity and yield. In three of eight site-years, the inoculated control had a relatively high disease severity compared to other seed treatments. In general, treatment responses varied across site-year due to low disease pressure. Additionally, F. graminearum and F. oxysporum were isolated at a high frequency from control plots at sites in 2019. Data from 2020 is pending.