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Individual study: Biology and control of parrotfeather (Myriophyllum aquaticum) in Portugal

Published source details

Moreira I., Monteira A. & Ferreira T. (1999) Biology and control of parrotfeather (Myriophyllum aquaticum) in Portugal. Ecology Environment and Conservation, 5, 171-179


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Parrot’s feather: Use of herbicides - diquat Control of Freshwater Invasive Species

A replicated, randomized, controlled, field study conducted in summer 1986 in Portugal (Moreira et al. 1999) found that the application of the herbicide diquat did not reduce the biomass of parrot’s feather Myriophyllum aquaticum. For three out of three comparisons, the fresh weight of parrot’s feather plants treated with diquat did not differ from untreated plants (15–25 vs 22–26 kg/m2). Additionally, the biomass of parrot’s feather plants treated with diquat (15–25 kg/m2) was higher than that of plants treated with 2,4-D amine (2–9 kg/m2) for three out of three comparisons, was higher than that of plants treated with gluphosinate-ammonium (9–22 kg/m2) for five out of nine comparisons, and was higher than of plants treated with glyphosate (9–14 kg/m2) for two out of three comparisons. Parrot’s feather biomass was assessed in 20 x 7 m plots and each herbicide rate was tested in four replicates. Herbicide rates were 2 kg/ha for diquat, 6.5 kg/ha for 2,4-D amine, 1–2.4 kg/ha for gluphosinate-ammonium and 3.6 kg/ha for glyphosate.

(Summarised by Ricardo Rocha)

Parrot’s feather: Use of herbicides - other herbicides Control of Freshwater Invasive Species

A replicated, randomized, controlled, field study conducted in summer 1986 in Portugal (Moreira et al. 2010), found that the application of the herbicide glyphosate reduced the biomass of parrot’s feather Myriophyllum aquaticum. For two out of three comparisons, the fresh weight of plants treated with glyphosate was reduced relative to untreated plants (9–14 vs 22–26 kg/m2). Additionally, four and a half months after treatment, the biomass of parrot’s feather plants treated with glyphosate (13 kg/m2) was higher than plants treated with 2,4-D amine (2.2 kg/m2), but lower than plants treated with diquat (18 kg/m2). Parrot’s feather biomass was assessed in 20 x 7 m plots, with four replicates of each herbicide. Herbicide rates were 2 kg/ha for diquat, 6.5 kg/ha for 2,4-D amine, 1–2.4 kg/ha for gluphosinate-ammonium and 3.6 kg/ha for glyphosate. Herbicide was applied twice in the same area.

(Summarised by Ricardo Rocha)

Parrot’s feather: Use of herbicides - 2,4-D Control of Freshwater Invasive Species

A replicated, randomized, controlled, field study conducted in summer 1986 in Portugal (Moreira et al. 1999) found that the application of the herbicide 2,4-D amine reduced the biomass of parrot’s feather Myriophyllum aquaticum. For three out of three comparisons, the fresh weight of parrot’s feather plants treated with 2,4-D amine was lower relative to untreated plants (2–9 vs 22–26 kg/m2). Additionally, four and a half months after treatment, the biomass of plants treated with 2,4-D amine (2.2 kg/m2) was significantly lower than that of plants treated with diquat (18 kg/m2), gluphosinate-ammonium (14–15 kg/m2) and glyphosate (13 kg/m2). Parrot’s feather biomass was assessed in 20 x 7 m plots and each herbicide rate was tested in four replicates. Herbicide rates were 6.5 kg/ha for 2,4-D amine, 2 kg/ha for diquat, 1–2.4 kg/ha for gluphosinate-ammonium and 3.6 kg/ha for glyphosate.

(Summarised by Ricardo Rocha)

Parrot’s feather: Use of herbicides - other herbicides Control of Freshwater Invasive Species

A replicated, controlled field study conducted in autumn 1995 in Portugal (Moreira et al. 2010) found that the application of the herbicide dichlobenil led to a smaller reduction in the cover of parrot’s feather Myriophyllum aquaticum than the combined application of the herbicides 2,4-D and MCPA eight days after treatment but not 45 days after application. Eight days after treatment, the cover of parrot’s feather plants treated with dichlobenil (85% cover) was higher than of plants treated with a combination of 2,4-D and MCPA (10%). However, after 45 days, the cover of plants treated with dichlobenil at a rate of 4.1 kg/ha (20%) was lower than of plants treated with a dicholobenil at a rate of 2.7 kg/ha (60%) or with a combination of 2,4-D and MCPA (60%). Each herbicide rate was sprayed onto three plots of 100 m2. Herbicide concentration was 520 g and 520 g/l for 2,4-D + MCPA respectively.

(Summarised by Ricardo Rocha)

Parrot’s feather: Use of herbicides - 2,4-D Control of Freshwater Invasive Species

A replicated, controlled field study conducted in autumn 1995 in Portugal (Moreira et al. 1999) found that the combined application of the herbicides 2,4-D and MCPA led to a greater reduction of the cover of parrot’s feather Myriophyllum aquaticum than the application of the herbicide dichlobenil eight days after treatment but not 45 days after application. Eight days after treatment, the cover of parrot’s feather plants treated with a combination of 2,4-D and MCPA was lower than of plants treated with dichlobenil (10% vs 85%). However, after 45 days, the cover of plants treated with 2,4-D and MCPA was higher than that of plants treated with dichlobenil at a rate of 4.1 kg/ha (60% vs 20%). Each herbicide rate was sprayed onto three plots of 100 m2. Herbicide rates were 2.7 kg/ha and 4.1 kg/ha for dichlobenil and 520 g and 520 g/l for 2,4-D and MCPA respectively.

(Summarised by Ricardo Rocha)

Parrot’s feather: Use of herbicides - other herbicides Control of Freshwater Invasive Species

A replicated, randomized, controlled, field study conducted in summer 1986 in three drainage channels Portugal (Moreira et al. 2010) found that the application of the herbicide gluphosinate-ammonium reduced the biomass of parrot’s feather Myriophyllum aquaticum in five out of nine comparisons. For five out of nine comparisons, the fresh weight of parrot’s feather plants treated with gluphosinate-ammonium was reduced relative to untreated plants (9–22 vs 22–26 kg/m2). Additionally, four and a half months after treatment, the biomass of parrot’s feather plants treated with gluphosinate-ammonium (14–15 kg/m2) was higher than plants treated with 2,4-D amine (2.2 kg/m2) but lower than plants treated with glyphosate (13 kg/m2). Parrot’s feather biomass was assessed in 20 x 7 m plots and each herbicide rate was tested in four replicates. Herbicide rates were 2 kg/ha for diquat, 6.5 kg/ha for 2,4-D amine, 1–2.4 kg/ha for gluphosinate-ammonium and 3.6 kg/ha for glyphosate. Herbicide was applied twice in the same area.

(Summarised by Ricardo Rocha)