The Effects of DMI Fungicide Applications on Secondary Metabolites in Creeping Bentgrass (Agrostis stolonifera) and Kale (Brassica oleracea var. acephala).

Propiconazole and tebuconazole are two triazole fungicides that were evaluated for their impact on the carotenoid pathway in creeping bentgrass (Agrostis stolonifera) and kale (Brassica oleracea var. acephala) when applied to plant foliage. Changes in carotenoid pigment concentrations in creeping bentgrass were investigated to determine if applications of propiconazole and tebuconazole could lead to an increase in stress protection. Kale was examined to determine if triazole applications could lead to an increase in carotenoids, which have been well documented for their role in human health. Because of the growing market for immature or baby leafy greens versus mature greens, two different maturation stages were used in this study. Plant pigment concentrations were determined using high performance liquid chromatography (HPLC) following two applications of propiconazole and tebuconazole.

Applications of propiconazole and tebuconazole significantly reduced the concentration of zeaxanthin in creeping bentgrass compared to the untreated control suggesting that treated plants were experiencing less stress than the untreated plants. Minor changes were observed in chlorophyll pigment concentrations, with only chlorophyll b being significantly increased in treated plants compared to the untreated control. Baby kale showed significantly increased neoxanthin, lutein, and total carotenoid concentrations, as well as increases in chlorophyll a and b, and total chlorophyll. Pigment concentrations in mature kale all decreased substantially compared to baby kale and no significant differences were found between treated and untreated plants. This suggests the possibility that triazoles could have a more pronounced effect on pigment concentrations in younger plants.