Mechanical flower and leaf removal (topping/harvesting) have a major role in the spread of bacterial wilt in the southeastern USA. Mechanical topping and harvesting can spread the pathogen rapidly from localized centers of infection throughout entire fields, resulting in massive epidemics and late season collapse of large fields. As a soilborne pathogen, Ralstonia solanacearum typically infects tobacco plants through direct penetration of roots. But with mechanical transmission, the infection site is foliar, occurring through topping wounds, leaf scars and stem abrasions by the direct mechanical action of topper blades, leaf defoliators and harvester guides. With the differences between root and foliar infection, the objectives of this study were to evaluate the aggressive of diverse R. solanacearum isolates when applied to foliar plant parts during flower removal (topping) and to determine if an Avr-induced resistance response found with certain isolates (tomato) in root tissue also occurs in stem tissue. The experiment was conducted on site at the Pee Dee Research & Education Center during the 2009 growing season. Plants of K346 were grown under standard agronomic practices for South Carolina. Twenty three isolates of Ralstonia solanacearum were selected for differences in genetic diversity and aggressiveness. Plots consisted of a single row of 10 plants and rows were fumigated with Telone C-17 before transplanting. The experimental design was a randomized complete block with 4 replications. Isolates of R. solanacearum were grown up on tetrazolium amended nutrient agar, re-suspended in deionized water and standardized to 1 x106 cells/ml. Inoculation simulated mechanical flower removal - a steel cutter blade was misted with the suspension of each isolate and used to top 10 plants. A water inoculated treatment was used as the control. The presence of the pathogen was confirmed by using an immunological assay (Agdia). Plants were assessed weekly for disease symptoms, starting 21 days after inoculation and rated on a 0 to 5 scale (0 = no visible symptoms, 5 = complete collapse of tissue). Stem necrosis was recorded on a 0 to 5 scale at the final disease assessment date. Disease severity data was subjected to ANOVA using JMP software (SAS) and AUDPC values were calculated for each treatment. There were significant differences in the amount of disease caused by the selected isolates of R. solanacearum when inoculated to foliar plant parts in the field. The resistance mechanism that functions against tomato strains in root infections also appears to function in tobacco stem tissue. Many of the isolates showed no measurable leaf/plant symptoms (tomato strains). Rankings of disease intensity measurements (leaf tissue) and stem necrosis were highly correlated (Correlation=0.987909). Rankings of isolates based on the level of disease in inoculated foliar plant parts were highly correlated with rankings shown by Robertson et al. (2001) in studies using inoculum applied to the soil.