VIEW ARTICLE

Factors Influencing Halo Blight Transmission from Externally Contaminated Phaseolus vulgaris Seed. James W. Guthrie, Associate Professor of Plant Pathology, Department of Plant Science, University of Idaho, Moscow 83843. Phytopathology 60:371-372. Accepted for publication 29 September 1969. DOI: 10.1094/Phyto-60-371.

Dry plant refuse from halo blight-infected bean leaves diluted 1:10 with talc and applied to halo blight-free Gallatin 50 seed can result in infected plants. Dilutions greater than 1:10 did not induce infection. The diluting effect of plant refuse from disease-free plants and from soil particles during commercial bean harvest probably reduced the amount of halo blight transmission from seed contamination. Surface-contaminated Pinto 114 seed did not result in infected plants regardless of the inoculum dilution. Secondary spread of halo blight occurred in 1966 following a hail storm, but not during the normal rainfall years of 1967 and 1968. All plants were sprinkler-irrigated.