SOIL AMENDMENTS AND WATER MOISTURE ON THE CONTROL OF TOMATO BACTERIAL WILT CAUSED BY RALSTONIA SOLANACEARUM

Bacterial wilt is one. of the most severe tomato diseases worldwide and Ralstonia solanacearum is determined to be the pathogen responsible for its spread. Soil amendments such as calcium cyanamide and herb residues have both been proved to be high potential for tomato bacterial wilt control. Disinfection effect and heat generated during the decomposition processes of calcium cyanamide and herb residues effectively controlled Ralstonia solanacearum while rare studies are conducted on their mechanisms. In this paper, calcium cyanamide was applied in combination with herb residues under solar greenhouse condition to evaluate their integrated control effects on tomato bacterial wilt. It promoted rapid temperature increases to above 40 degrees C within 15 days. R. solanacearum was decreased to the lowest population (5.38 log cfu/g) at 20 d and no recovery was found after treatment. In addition, the optimal soil moisture content for pathogen control was also discussed. Under soil moisture of 85% field capacity, tomato treated with calcium cyanamide and herb residues had the most favorable growing performance with wilt of 3.6% and wilt control efficiency of 79.8%.