The effect of the extremely low frequency (ELF) electromagnetic (EM) field on the growth of Ralstonia solanacearum was studied where the bacterial suspensions were exposed to different frequencies of square amplitude modulated waves (QAMW) in the range of 0.7-1.2 Hz in steps of 0.1Hz to determine the resonance frequency of growth inhibition. The exposure time varied in a range of 15min-2h. The results indicated that under the best conditions with the electromagnetic field treatment (exposure to 1 Hz QAMW for 1 h) the growth of the exposed bacteria was lower than the control one by 66.43%, this difference was highly significant. In addition, the antibiotics susceptibility test using Sulfamethoxazole and Trimethoprim (SXT) and Tetracycline (TE) which act as inhibitors for DNA and protein synthesis was done for both control and exposed bacteria indicated highly significant differences in the susceptibility between control and group exposed to l.0 Hz QAMW. It could be concluded that the application of ELF EM field could be used to control the disease and in disinfecting potato tubers in storage and before planting.