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ARS Home » Northeast Area » Frederick, Maryland » Foreign Disease-Weed Science Research » Research » Publications at this Location » Publication #397313
Research Project: Diagnostics and Biological Approaches for Management of Emerging Oomycete Plant Pathogens

Location: Foreign Disease-Weed Science Research

Title: High incidence of Hyaloperonospora cardamines-laciniatae on Cardamine concatenata in Maryland, USA

Author
item Pfeufer, Emily
item Harrison, Lindsay

Submitted to: New Disease Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/12/2022
Publication Date: 12/19/2022
Citation: Pfeufer, E., Harrison, L.K. 2022. High incidence of Hyaloperonospora cardamines-laciniatae on Cardamine concatenata in Maryland, USA. New Disease Reports. 46:e12143. https://doi.org/10.1002/ndr2.12143.
DOI: https://doi.org/10.1002/ndr2.12143

Interpretive Summary: Cardamine concatenata, or cutleaf toothwort, is an understory plant native to eastern U.S. forests with a very short lifecycle each year. Cutleaf toothwort as well as other Cardamine species are critical hosts for Pieris spp. butterflies, which are threatened by poor juvenile performance on nonnative invasive plants, like garlic mustard. Pieris spp. butterflies mistakenly lay eggs on the invasive garlic mustard, which never mature. In 2022, extremely severe downy mildew was identified on cutleaf toothwort in Maryland, USA. The pathogen, Hyaloperonospora cardamines-laciniatae, was identified through microscopy and DNA sequence based methods. Photos of H. cardamines-laciniatae symptoms, structures, and spores are published here for the first time. The impact of H. cardamines-laciniatae on cutleaf toothwort overwintering, seed viability, and foliar longevity is not known, each of which is potentially impactful to Pieris spp. butterfly survival.

Technical Abstract: Hyaloperonospora cardamines-laciniatae causes very severe downy mildew on Cardamine concatenata (cutleaf toothwort), a spring ephemeral plant native to eastern U.S. forests. C. concatenata is a critical host for native Pieris spp. butterflies, whose populations are threatened due to poor reproductive performance on nonnative, invasive plants like Alliaria petiolata (garlic mustard). The impacts of H. cardamines-laciniatae on C. concatenata seed viability, foliar longevity, and vegetative overwintering are not known, but any of these could threaten populations of these plants, and indirectly, the Pieris spp. that rely on them.