Abstract

Bacterial wilt caused by Ralstonia solanacearum is a major constraint in tomato production. Experiments were carried out using four sanitised plants and solarization in a semi- controlled environment and in the field to reduce the infectious potential of the soil in R. solanacearum. The experimental design used is a randomized Fisher block with eight (8) treatments composed of Ocimum basilicom, Ocimum gratissimum, Allium cepa, Crotalaria retusa, solarization, untreated control, bactericide (IDEFIX) and the biocontrol indicator (Rossol). Seventy days after the implementation in the field, the initial infectious potential of 1.07×10⁸ CFU g^-1 of dry soil increased to 4.11×10⁷ CFU g^-1 of dry soil, an average reduction of 55.63%. O. gratissimum is the best sanitizing plant with 68.18% reduction in the infectious potential of the soil. In a semi-controlled environment C. retusa recorded the greatest reduction (73.96%) of the infectious potential of the soil among the sanitizing plants. The greatest reductions in disease incidence in the field were observed with solarization (60%) followed by C. retusa (58%).

Key words: Ocimum basilicom, Ocimum gratissimum, Infectious potential, Sanitizing, tomato, semi-controlled environment.