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

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 significant antifungal activity (P<0.05); in particular, the extract from one accession of Picea pungens Engelm. had significant effective fungistatic and fungicidal activity (P<0.05), 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. Further investigations will focus on the potential of this extract as an alternative to traditional fungicides for use in a wide range of crops and in diverse applications from controlling fungal infections in the landscape to preventing post-harvest losses in fruit and vegetable crops.