Abstract
SUMMARY: When a column of air-dried soil was perfused with a mineral salt solution containing ‘Dalapon’ (Dow Chemical Company, Michigan), the concentration of dichloropropionate (Dalapon's herbicidal component) became minimal in 15--17 days. The soil was reperfused and the dichloropropionate became minimal in 4--5 days. Three strains of the genus Pseudomonas, exhibiting a requirement for dichloropropionate, were isolated from the perfusate. Two strains attacked dichloropropionate when allowed to perfuse through sterilized soil. A further seven micro-organisms, with a similar requirement, were isolated from pasture soils treated with Dalapon.