VIEW ARTICLE

Effect of Freezing Injury on Head Rot and Spot of Cabbage. Donald R. Sumner, Assistant Professor, Department of Plant Pathology, University of Georgia, Coastal Plain Experiment Station, Tifton 31794; Phytopathology 62:322-325. Accepted for publication 4 October 1971. DOI: 10.1094/Phyto-62-322.

The cabbage cultivar Market Prize was transplanted in September and October and inoculated with several bacteria with or without artificial wounding in November, December, and January. Temperatures of –5 to –8 C occurred 6 times during the winter. Heads were harvested as they matured in December to April. The percentage of nonwounded plants producing salcable heads was significantly reduced by inoculations with Pseudomonas cichorii and P. maculicola in November, but not in later months. Wounding significantly increased damage caused by P. maculicola but not by P. cichorii. Frequently, heads had severe internal damage but no external discoloration similar to head rot observed in commercial fields. Tan to brown target lesions were caused by P. cichorii, and purplish-black to black lesions by P. maculicola. An isolate of Erwinia caused a soft, gray rot with a putrid odor. No appreciable damage was caused by P. marginalis. Younger plants were more severely damaged than older plants. The percentage of plants killed or damaged with multiple heads, hollow stems, or bolting was significantly increased by P. cichorii and P. maculicola. When the remaining nondamaged young plants began rapid growth in the warm spring months, the discolored tissue was usually confined to the exterior of the heads.