Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: 3/1/2001
Publication Date: 6/1/2001
Citation: Copes, W.E. 2001. Influence of select inorganic ions and ph on fungicidal activity of chlorine dioxide in water. Phytopathology. 94:S21
Technical Abstract: Chlorine dioxide (ClO2) can be used to control pathogen propagules in irrigation water and on production surfaces wet within a sprinkler zone. To determine to what degree inorganic ions and pH that occur in water systems can effect ClO2 activity, various concentrations of ClO2 were mixed with various concentrations of ammonium (NH4), nitrate (NO3), copper (Cu), iron (Fe),manganese (Mn), zinc (Zn), and synthetic hard water (HW) at different pH levels. After 10 minutes of mixing, spores of Botrytis cinerea, Fusarium oxysporum, and Thielaviopsis basicola were exposed to test solutions for 30 seconds; then suspensions poured through filter paper disks. Disks were flushed with water and plated on 50% potato dextrose agar. Germination was quantified at 1 and 3 days. Water amendments significantly affected ClO2 activity similarly for all species, but the lethal concentration of ClO2 differed by species and propagule type. ClO2 activity was unaffected by NH4, NO3, Zn, and pH 4; slightly reduced by Cu, HW, and pH levels 5-8; moderately reduced by Fe; highly reduced by Mn; and severely reduced by pH 9 and 10.