Efectividad diferencial de extractos de espárrago frente a la podredumbre radical causada por Phytophthora cinnamomi

Asparagus waste constitutes a significant source of bioactive compounds (phenols and saponins) that are toxic to soil pathogens such as Phytophthora cinnamomi, the primary cause of Oak Decline. The main objective of this study was to determine the biocidal activity against P. cinnamomi of three extracts rich in phytochemical compounds from asparagus crop residues (stems, fronds, and roots). Through in vitro experiments, the effect of these three extracts at a dose of 0.05% was determined to inhibit the infective capacity (sporangia production) of P. cinnamomi. All extracts achieved inhibition greater than 50%, with the asparagus stem extract showing 95% inhibition. Additionally, in vivo assays determined the activity of these extracts at the same dose on the pathogen's survival capacity. Two weeks after applying the extracts to a substrate previously infested with P. cinnamomi chlamydospores, a significant reduction in the density of viable spores was observed in all treatments compared to the untreated control. At this point, Lupinus luteus seedlings were transplanted to evaluate the effect on root disease development. After six weeks of incubation, seedlings growing in substrate treated with asparagus stems showed significantly fewer root symptoms than those growing in untreated infested substrate. These results consistently demonstrate the effectiveness of asparagus stem extract in controlling the infectivity, survival, and development of root disease caused by P. cinnamomi.