2004 Volume 19 Issue 1 Pages 53-60
Different composts were added to a conducive soil to study their effects on the bacterial wilt of tomato caused by Ralstonia solanacearum. The soils to which bark compost, coffee manure and pork manure were added showed higher wilt incidence (more than 5 plants out of 6 wilted) after 30 days of cultivation compared to those in the non-treated soil, while the soils with poultry and farmyard manure (FYM) showed consistently lower wilt incidence (less than one plant out of 6 wilted). Survival of the pathogen was better in the control and in the bark, coffee and pork manure added soils than in the poultry and FYM added soils. A lower C/N ratio and higher amounts of water soluble organic carbon and nitrogen were found in the poultry and FYM than the other composts, suggesting that the contents of easily decomposable organic matters might be higher in the added soils. This was supported by higher numbers of culturable bacteria and fungi and higher microbial activity (measured by CO2 emission and dehydrogenase activity) in the poultry and farmyard manure added soils than in the other compost added soils. This study demonstrated that the bacterial wilt of tomato was suppressed in the poultry and FYM added soils, and higher microbial activity was likely responsible.
