The study evaluated the effect of prior plant cutting of common reed (Phrag
mites australis), during flowering, on the efficacy of isopropylamine and t
rimesium salts of glyphosate (2.9 and 2.6 kg a.i./ha, respectively) applied
at two spray volumes in the following spring. Efficacy was measured by pla
nt cover (% control), number of plants/m(2) and plant biomass/m(2). A posit
ive effect of the plant cutting was observed when plant cover and number of
plants/m(2) were measured. The evaluation of herbicide phytotoxicity on pl
ant biomass did not show significant differences. Common reed susceptibilit
y to isopropylamine and trimesium salts of glyphosate was similar. Signific
ant differences between the spray volumes of 320 and 400 l/ha were observed
only in plant cover estimates. The 400 l/ha spray volume showed higher eff
icacy.