Evaluation of a novel fungicidal extract from blue spruce, Picea pungens

Authors: Guo, Yonghong; Zhou, Bin; Pooler, Margaret

Submitted to: Plant Health Progress
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/10/2024
Publication Date: 6/3/2024
Citation: Guo, Y.H., Zhou, B., Pooler, M.R. 2024. Evaluation of a novel fungicidal extract from blue spruce, Picea pungens. Plant Health Progress. https://doi.org/10.1094/PHP-10-23-0089-RS.
DOI: https://doi.org/10.1094/PHP-10-23-0089-RS

Interpretive Summary: Natural compounds derived from plants can be effective at controlling plant fungal pathogens. ARS scientists in Beltsville, MD screened extracts from diverse, well-documented plant germplasm curated at the U.S. National Arboretum, with the goal of identifying one or more taxa that might have potential for developing biorational products to control fungal plant pathogens. The extract from one accession of blue spruce (Picea pungens) was particularly effective in initial screens, so was tested further in lab assays and on plants. Based on these results, this extract from blue spruce may offer an alternative to traditional fungicides for use in a broad spectrum of crop plants and in diverse applications from controlling fungal infections in the landscape to preventing post-harvest losses in fruit and vegetable crops.

Technical Abstract: Aqueous extracts from 22 species of evergreen plants and 32 accessions of spruce (Picea A.Dietr.) were screened using an in vitro assay to determine their anti-fungal activity against Calonectria henricotiae, one of the causal agents of boxwood blight. Most of the evergreen species and all the spruce accessions showed at least some antifungal activity; however, extract from one accession of Picea pungens Engelm. had particularly effective fungistatic and fungicidal activity, both in vitro and when tested on detached boxwood leaves and whole boxwood plants. The extraction process was simple, consisting of autoclaving fresh leaves in water, and once extracted, the active compound was stable in aqueous solution and when lyophilized and reconstituted. This extract could lead to an alternative to traditional fungicides for use in a broad spectrum of crop plants and in diverse applications from controlling fungal infections in the landscape to preventing post-harvest losses in fruit and vegetable crops.