Evaluating Chlorine Dioxide (ClO2) & Hydrogen Peroxide (H2O2) as Disinfectants Against Verticillium dahliae in Soilless Pepper Crops

Le résumé fourni par la source

Recycling drainage solutions (DS) in closed-loop soilless culture systems reduces fertilizer and water consumption in greenhouse production while preventing environmental pollution caused by nitrogen and phosphorus emissions. However, recycling DS increases the risk of spreading root- infective pathogens through the irrigation system, making disinfection necessary prior to reuse. In this study, two oxygen-containing oxidizing agents, hydrogen peroxide (H₂O₂) and chlorine dioxide (ClO₂) were evaluated as nutrient solution (NS) disinfectants against Verticillium dahliae. The experiment was conducted in a closed-loop soilless pepper crop grown in a greenhouse during the spring–summer period. All treatments received nutrient solutions (NS) of identical composition. Three treatments were applied with three replicates each: (i) non-treated NS (control), (ii) NS supplemented with 2 ppm ClO₂, and (iii) NS supplemented with 2 ppm H₂O₂. Six-week-old pepper plants were inoculated with V. dahlia strain 402V. Both disinfectants significantly improved pepper fruit yield and quality compared with the non-disinfected control. ClO₂ resulted in the highest number of marketable fruits and total fruit yield, while both ClO₂ and H₂O₂ reduced unmarketable fruits and increased average fruit weight. Pathogen biomass quantification by qPCR demonstrated that ClO₂ significantly reduced pathogen presence in the hydroponic system, achieving approximately 63% lower biomass compared with the untreated control. In contrast, H₂O₂ showed limited efficacy and pathogen levels comparable to the control treatment. Application of H₂O₂ and ClO₂ significantly enhanced mineral accumulation in pepper tissues, increasing macronutrient (P, K, Mg, Ca) and micronutrient (Fe, Zn, Cu) concentrations compared with the control treatment.

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