Development of suppressiveness to root rot caused by Cylindrocladium spathiphylli in container media amended with marine residues

Abstract: This study aimed at evaluating the potential of fish hydrolyzed (FH), fish emulsion(FE), shrimp peel powder (SP), Sargassum seaweed powder (SW) and mussel shell powder (MS)to induce suppressiveness against Cylindrocladium spathiphylli in container media. In thecontainer media, naturally infested, FH and FE at concentrations of 0, 5, 10, 15, 20 and 25% (v/v)of the volume of water required to reach the water retention capacity of the container media, andSP, SW and MS at concentrations of 0, 1, 2, 3, 4 and 5% (v/v) were incorporated. The mixtureswere incubated for 10 days at room temperature. Afterwards, the mixtures were transferred toplastic pots of 300 ml, followed by the planting of one plug of Spathiphyllum ‘Opal’/pot. Whenplanting, at 90 and 180 days of cultivation, microbial respiration, carbon microbial biomass(MBC), and fluorescein diacetate hydrolysis (FDA) were determined. The incidence wasevaluated after 180 days and disease severity was assessed weekly throughout until 180 days. Toconfirm the causal agent of disease in plants, root fragments were placed in Petri dishescontaining PDA + streptomycin, kept in a growth chamber. Fish hydrolyzed, FE, and SP reducedthe incidence and the area under curve of progress disease (AUCPD). Fish emulsion at 20%showed the highest dry matter and the lowers recurrence of the pathogen in 180 days. Hydrolysisof diacetate of fluorescein, respiration of container media, and carbon microbial biomass showedquadratic effect at concentrations of FH, FE and SP, with the inflection point at 25, 20 and 3%,respectively. We concluded that FE at 20% (v/v) promoted the greatest suppressiveness toC. spathiphylli, as well as increased plant development.