VIEW ARTICLE

A Boll Rot of Cotton Caused by Phytophthora parasitica. J. A. Pinckard, Professor, Louisiana Agricultural Experiment Station, Baton Rouge 70803; Gerald F. Guidroz, Assistant Professor, Department of Biological Sciences, Southeastern Louisiana University, Hammond 70401. Phytopathology 63:896-899. Accepted for publication 23 January 1973. DOI: 10.1094/Phyto-63-896.

A Phytophthora boll rot of cotton (Gossypium hirsutum) has been found widely distributed in Louisiana. Six of 12 isolates from rotted bolls collected from different cotton-producing areas were compared on a variety of media and test plants. The six isolates were each highly pathogenic and produced similar symptoms upon contact with healthy bolls. Morphological characters, growth on various media, growth at stated temperatures and hydrogen ion concentrations revealed no obvious differences among the isolates. All evidence indicated the six isolates to be the same species, P. parasitica = P. nicotianae var. parasitica.