EN
Examination of biological activity of 537 new chemical compounds against algae and duckweed was the experimental objective. Among compounds studied only four revealed algicidal activity. They were as follows: dodecyldimethyl(5-hydroxyazomethine-2-methoxy)benzylammonium chloride (IPO--6773); 1,2-dimethyl-3-dodecyloxymethylimidazolium chloride (IPO-8958); 1-octyl-3-octyloxymethylimidazolium chloride (IPO-7833); diethyl dodecylamino(dipropylo)methylphosphonate (IPO-10569). These compounds should be used in the practice of redudant aquatic vegetation control.