VIEW ARTICLE

Disease Detection and Crop Losses

Injury and Yield Responses of Peanuts to Chronic Doses of Ozone in Open-Top Field Chambers. Allen S. Heagle, Plant pathologist, Agricultural Research Service, U.S. Department of Agriculture, Department of Plant Pathology, North Carolina State University, Raleigh 27650; Michael B. Letchworth(2), and Colleen A. Mitchell(3). (2)(3)Research assistants, Department of Plant Pathology, North Carolina State University, Raleigh 27650. Phytopathology 73:551-555. Accepted for publication 15 October 1982. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1983. DOI: 10.1094/Phyto-73-551.

Peanuts were exposed during 1979 and 1980 to concentrations of ozone (O₃) that spanned those that occur in ambient air of peanut production areas in the United States. The different concentrations were obtained by adding O₃ to the air of open-top field chambers for 7 hr per day from the seedling stage to harvest. Ozone at seasonal 7-hr per day concentrations (mean concentration for 7 hr per day during the seasonal exposure period) equal to, or greater than, the ambient concentration caused foliar injury and decreased shoot and root weight for both years. Seasonal 7-hr per day O₃ concentrations in ambient air at our field site near Raleigh, NC, were 0.052 and 0.056 ppm for 1979 (131 days) and 1980 (112 days), respectively. In 1979, marketable pod weight (yield) per plant at seasonal 7-hr per day O₃ concentrations of 0.049, 0.072, and 0.096 ppm was 0, 30, and 37% less, respectively, than for control plants in chambers that received charcoal-filtered air with a seasonal concentration of 0.026 ppm O₃. In 1980, yield at seasonal O₃ concentrations of 0.056, 0.076, 0.100, and 0.125 ppm was 14, 35, 52, and 72% less, respectively, than for the control treatment (0.025 ppm). Linear regression equations using data from 1979 and 1980 predicted yield losses of 17 and 21%, respectively, at a seasonal 7-hr per day mean O₃ concentration of 0.054 ppm.