The herbicides chlorthiamid and dichlobenil inhibited the growth of some actinomycetes in starch-casein medium. The effect of these herbicides on the other bacteria tested was insignificant. Chlorthiamid and dichlobenil arc slowly degradable herbicides. Bacteria such as Arthrobacter, unidentified coryneforms and Bacillus could degrade the herbicides by cometabolism. 2,6-Dichlorobenzamide, 2,6-dichlorobenzoic acid, carbon dioxide, chloride, a catechol compound and many unidentified compounds were found as metabolites. Arthrobacter strains capable for dechlorination could also cleave the aromatic ring, both processes occurring in aerated cultures. More than half of the chloride was liberated in three weeks at 28°C by the most active Arthrobacter strain
