VIEW ARTICLE

Microdensitometer Measurements of Sequential Aerial Photographs of Field Beans Infected with Bacterial Blight. H. R. Jackson, Research Program Services Section, Research Branch, Agriculture Canada, Ottawa, Ontario K1A OC6; V. R. Wallen, Ottawa Research Station, Research Branch, Agriculture Canada, Ottawa, Ontario K1A OC6. Phytopathology 65:961-968. Accepted for publication 24 March 1975. DOI: 10.1094/Phyto-65-961.

Optical density levels were determined from aerial photographs of healthy and bacterial (Xanthomonas phaseoli) blight-infected bean plots throughout the growing seasons in 1971 and 1972. Three films, Kodak Aerochrome Infrared 2443, Kodak Ektachrome MS Aerographic 2448, and Kodak Infrared Aerographic 2424 were used in 1971. Only Kodak Aerochrome Infrared 2443 was used in 1972. Changes in diseased plots were not apparent in the films exposed during July despite the onset of infection following inoculation of the plots in late June. Density levels between healthy and diseased plots showed obvious differences from 2 August 1972 and 5 August 1971 and throughout the growing season.