The extracts of nine seaweed species[A1]  in three different solvents (methanol, dichloromethane/methanol, and dichloromethane) were examined in vitro for their antimicrobial properties against two pathogenic microorganisms: Pectobacterium carotovorum and Fusarium sp < em>. responsible of root rot in sugar beet and resulting in yield shortages and economic losses. This study showed that dichloromethane extract from Plocamium cartilagineum has the maximum inhibition against the growth of both pathogens under study, with a zone value ranging from 17.5 to 34mm, respectively. These results suggest that red seaweed Plocamium cartilagineum contains compounds that could be considered for controlling root rot in sugar beet. Thus, the composition of dichloromethane extract from Plocamium cartilagineum was determined by gas chromatography/mass spectroscopy (GC/MS) analysis. The main compounds detected were selenocyanic acid (20.77%), oleic acid (10.52%), and 9, 12, 15 octadecatrienoic acid (Z, Z, Z) (9.30%).  [A1]you mean seaweed extracts in 3 different solvents? Kindly reconsider the meaning.