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Pseudomonas syringae pv. maculicola (P. maculicola) has become important in California in certain situations. In 1982-83, a year of above-normal rainfall, cauliflower (Brassica oleracea L. var. botrytis) had severe necrosis on the stems in the curd. This symptom was reported once previously by E.F. Smith and has been reproduced on three cultivars of cauliflower in a field trial at Davis in the winter. P. maculicola also has caused severe infection of cauliflower seedlings in transplant-producing greenhouses. During the rainy winter season, the symptoms produced by Xanthomonas campestris pv. campestris may be atypical of those produced in warm weather and mimic those produced by P. maculicola. Accurate diagnosis requires isolation of the causal bacterium. Bacterial leafspot has caused severe damage to occasional crops of pak choy (B. rapa L. var chinensis) grown in the winter. Finally, bacterial leafspot has been one of the most common diseases affecting leaves, stems, and seed pods of rape (B. juncea Czern. & Coss) being grown for evaluation as a winter crop in the Sacramento Valley. |
