Antagonistic effect of Bacillus thuringiensis for the control of bacterial wilt of tomato (Lycopersicon esculentum Mill)

Abstract

Tomato is affected by a lot of diseases including bacterial wilt caused by Ralstonia solanacearum (Rs), resulting in fruit yield loss. Chemical control of this disease is not advisable because of hazardous effects on human and environment, hence, the need to use biocontrol agents such as Bacillus thuringiensis (Bt). This study investigated the potential of Bt in the control of Rs under screenhouse condition. Six treatments with three replications in completely randomized design were carried out. Agronomic parameters were measured and data collected were analyzed using one - way analysis of variance. Means were then separated using Duncan's Multiple Range Test at p ≤ 0.05. Inoculation of Bt and Rs simultaneously significantly suppressed the incidence of bacterial wilt and promoted plant growth. Higher plant heights (72.70 - 111.00 cm), stem girth (1.63 - 1.90 cm) and number of leaves (103.33 - 125.33) were recorded for plants inoculated with Bt at 9th week after planting compared to plants inoculated with Rs alone. Highest disease incidence was recorded in plants inoculated with Rs alone (100 %), while plants inoculated with Bt had the highest disease reduction (67%). This study revealed that Bt may be used in the control of bacterial wilt of tomato.

Keywords: Bacillus thuringiensis, screenhouse, Bacterial wilt, Ralstonia solanacearum, Tomato