VIEW ARTICLE

Verticillium albo-atrum: the Quantitative Relationship Between Inoculum Density and Infection of Cotton. L. J. Ashworth, Jr., Department of Plant Pathology, University of California, Berkeley 94720; O. D. McCutcheon(2), and A. G. George(3). (2)(3)Farm Advisors, University of California, Kings and Tulare Counties, California. Phytopathology 62:901-903. Accepted for publication 21 February 1972. DOI: 10.1094/Phyto-62-901.

The threshold of infection for cotton plants by Verticillium albo-atrum was about 0.03 microsclerotia/g soil, under field conditions. Twenty to 50% infection occurred at the end of the growing season when the inoculum density was 0.3 to 1.0 microsclerotia/g soil, and essentially 100% infection occurred where the inoculum density was 3.5 or more microsclerotia/g soil.