Effects of Two-Year Crop Rotations and Cultivar Resistance on Bacterial Wilt in Flue-Cured Tobacco. T. A. Melton, Assistant Professor, Department of Plant Pathology, North Carolina State University, Raleigh 27695. N. T. Powell, Professor Emeritus, Department of Plant Pathology, North Carolina State University, Raleigh 27695. Plant Dis. 75:695-698. Accepted for publication 18 December 1990. Copyright 1991 The American Phytopathological Society. DOI: 10.1094/PD-75-0695.

The incidence of bacterial wilt, caused by Pseudomonas solanacearum, was reduced and the yield of flue-cured tobacco (Nicotiana tabacum) was increased by cultivar resistance and by 1-yr rotation to corn, fescue, or soybeans as compared with continuous tobacco. In general, crop value and yield were higher and disease index lower when tobacco was grown after soybeans than after fescue, corn, or tobacco. The value, yield, and disease index for tobacco grown after corn and after fescue did not differ. In contrast, value and yield were lowest and disease index was highest for continuous tobacco. The rotation used had a greater effect on the disease index in the more susceptible of the three tobacco cultivars planted. The disease index was 2.7–4.8 times higher in the more susceptible cultivar, whereas yields were 1.1–2.3 times higher in 2 of the 3 yr for the more resistant cultivar. When plots were fumigated with 1,3-dichloropropene + chloropicrin, yield was 8.4% higher but the disease index was not affected.

Keyword(s): Granville wilt.