P-683 - Initial Detection and Characterization of Downy Mildew Affecting Camelina in Tennessee

Monday, August 4, 2025

4:30 PM - 5:15 PM HST

Location: Exhibit Hall 3

Presenting author(s)

BB

Bailey Burns

University of Tennessee
Knoxville, Tennessee, United States

Author(s)

JH

Jensen Hayter

Assistant Professor, Extension Specialty Crop Pathologist
University of Tennessee, Knoxville
Knoxville, Tennessee, United States
VS

Virginia Sykes

University of Tennessee
Knoxville, Tennessee, United States

Abstract Text: Camelina (Camelina sativa) is a winter oilseed species identified for use as an off-season cover crop and source of biofuel. While well suited for integration into Tennessee crop rotations, limited information is available on disease pressure and impact. In spring 2025, symptoms indicative of the oomycete pathogen downy mildew (Hyaloperinospera sp) were observed on camelina in Tennessee, affecting plant stems and developing siliques. Morphological analysis confirmed downy mildew on leaf and stem tissue. Infected plant tissues exhibited white sporulation with deformity and curling of developing pod clusters. These symptoms were most prominent during periods of extended moisture and mild temperatures in the spring. Symptoms were present in all plots. Infection was localized on stems and pods, primarily at the reproductive stage. Symptom intensity ranged from mild sporulation on stems and pods, to visible deformation of multiple stem tips per plant. While no plants were fully colonized, the presence of this pathogen raises concern for potential yield loss due to the deformation of seed pods. To establish camelina as a viable biofuel source in Tennessee, molecular identification of the pathogen and evaluation of current management strategies will be necessary. To our knowledge, this is the first confirmed incidence of downy mildew on camelina in Tennessee.