Submitted to: Southern Nursery Association Research Conference
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/1/2004
Publication Date: 6/1/2003
Citation: Copes, W.E., Chastagner, G.A., Hummel, R.L. 2003. Toxicity responses of herbaceous and woody ornamental plants to chlorine and hydrogen dioxides. Southern Nursery Association Research Conference Proceedings. 47:215-218 Interpretive Summary: Hydrogen dioxide and chlorine dioxide are disinfectants registered for certain horticultural applications. Information about effective rates and strategies that would allow these disinfectants to be used to control pathogens on ornamental plants is limited. This study used different rates of these disinfectants believed to be effective for disease control to see if damage occurred on various ornamental plant species. Rates of hydrogen and chlorine dioxides that should control disease causing organisms did not damage most of the plant species tested. These results provide meaningful parameters that will allow research scientist to develop efficacy and spray strategies for these disinfectants. The use of these disinfectants in this manner will minimize use of fungicides while improving disease control.
Technical Abstract: To determine potential toxicity problems associated with foliar applications, chlorine dioxide (ClO2), at 2, 5, 20, 50, 100, 200, 1000, and 2000 and hydrogen dioxide (H2O2), at 900, 2700, 5400, and 10200 ppm, were sprayed five times at 3 day intervals on eight bedding plants and nine shrub species. Injury to leaves and flowers was rated by surface area exhibiting damage using Barrett-Horsfall categories, with marketability being reduced if 4 % surface area was affected. Rates of 2, 5, 20, and 50 ppm ClO2 and 900 and 2700 ppm H2O2 did not damage most plants tested and will likely control most common pathogen propagules. Rates of 100 ppm ClO2 and 5400 ppm H2O2 did not damage most plants tested if sprayed less than four consecutive times and should control some of the more chemical-tolerant pathogens.