VIEW ARTICLE

Response of Indicator Plants to Ozone Levels in Georgia. Jerry T. Walker, Department of Plant Pathology, University of Georgia, College of Agriculture Experiment Stations, Georgia Station, Experiment 30212; James C. Barlow, Air Quality Control Section, Georgia Department of Natural Resources, Atlanta 30334. Phytopathology 64:1122-1127. Accepted for publication 23 March 1974. DOI: 10.1094/Phyto-64-1122.

Bel-W 3 tobacco and Snowstorm petunia, exposed to ambient air beneath antiozonant-treated cloth at seven Georgia locations, generally were taller and weighed more than companion plants under nontreated cloth chambers. Ratings of foliar injury on Bel-W 3 were less, but not always significantly, on plants in treated chambers than in nontreated chambers. Oxidant levels, monitored in Atlanta, the state's largest city, averaged 2.6 pphm hourly for April, May, June, and July, 1971; sixteen episodes of concns greater than 5 pphm for 5 h or longer occurred during these months. Injury, typical of fluoride, occurred regularly on Snow Princess gladiolus at one location only, irrespective of chamber or exposure period. Ozone is present at sufficient concns in both urban and rural Georgia to cause injury and retard growth of indicator plants.