Parrot’s feather: Use of herbicides - carfentrazone-ethyl

How is the evidence assessed?
  • Effectiveness
    50%
  • Certainty
    40%
  • Harms
    5%

Source countries

Key messages

  • Five laboratory studies (including one replicated, controlled, before-and-after study) in the USA found that carfentrazone-ethyl reduced growth in parrot’s feather.

About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

  1. A small, replicated, controlled, before-and-after, laboratory study conducted in 2003 in the USA (Glomski et al. 2006), found that the application of the herbicide carfentrazone-ethyl reduced growth in parrot’s feather Myriophyllum aquaticum but did not lead to plant death. After 28 days, the biomass of parrot’s feather shoots treated with carfentrazone-ethyl was 29.5–54% lower than untreated plants. However, emerged and submerged foliage remained viable. The study was carried out using 12 1,600 l containers filled with water, each of which contained eight 5 l containers with three 15 cm parrot’s feather stems. Each of the three tested herbicide rates (50, 100 and 200 μg/l) was applied to three 1600 l containers, and plants in three containers were left untreated. Plants from four of the eight 5 l plastic containers placed inside each 1600 l container were harvested, dried and weighed before herbicide application, and the remaining plants were harvested, dried and weighed 28 days after herbicide application.

    Study and other actions tested
  2. A small, replicated, randomized, controlled, laboratory study conducted in 2004 in the USA (Gray et al. 2007), found that the herbicide carfentrazone-ethyl reduced growth in parrot’s feather Myriophyllum aquaticum. After three weeks, young parrot’s feather plants treated with carfentrazone-ethyl had a lower dry weight (1.8–2.4 g/pot) than untreated plants (6.4–10 g/pot). Parrot’s feather shoots were propagated in 3.9 l plastic containers. Carfentrazone-ethyl application rate ranged between 100 and 200 μg/l and each herbicide rate was applied to three plants.

    Study and other actions tested
  3. A small, replicated, controlled, laboratory study conducted in the USA (Richardson et al. 2008), found that the herbicide carfentrazone-ethyl reduced growth in parrot’s feather Myriophyllum aquaticum. Parrot’s feather plants treated with carfentrazone-ethyl had a lower dry weight (0.55–0.88 g) than untreated plants (1.43 g). Parrot’s feather shoot tips (5–10 cm) were transplanted into 9 cm2 pots. Carfentrazone-ethyl application rate ranged between 56 and 224 g/ha and each herbicide rate was applied to pots with three plants and plants in one pot were left unsprayed. Dates of the studies are not presented.

    Study and other actions tested
  4. A small, replicated, randomized, controlled, laboratory study conducted in 2006 in the USA (Wersal et al. 2010), found that the application of the herbicide carfentrazone-ethyl reduced growth in parrot’s feather Myriophyllum aquaticum. After four weeks, the dry weight of parrot’s feather plants treated with carfentrazone-ethyl was lower than untreated plants (1–2.1 vs 4.6 g/pot). Daytime and night-time application of the herbicide resulted in similar results. Parrot’s feather shoots were propagated in 3.78 l pots and placed inside 246 l containers filled with water. Each herbicide rate (0.1 and 0.2 mg/l) was applied to three plants.

    Study and other actions tested
  5. A small, replicated, controlled, laboratory study conducted between 2007 and 2008 in the USA (Wersal & Madsen 2010) found that the application of the herbicide carfentrazone-ethyl reduced growth of parrot’s feather Myriophyllum aquaticum. After six weeks, the dry weight of parrot’s feather plants treated with carfentrazone-ethyl was lower (10–12 g/pot) than that of untreated plants (18 g/pot). Six weeks after application, plants treated with carfentrazone-ethyl were reduced by 0–15% (visual assessment with 0% corresponding to no reduction in cover relative to untreated plans and 100% to complete elimination). Parrot’s feather shoots were propagated in 3.78 l pots and placed inside 246 l containers filled with water. Each herbicide rate (0.1 and 0.2 mg/l) was applied to four 246 l containers, each holding four plants. Number of plants used as control is not presented.

    Study and other actions tested
Please cite as:

Aldridge, D., Ockendon, N., Rocha, R., Smith, R.K. & Sutherland, W.J. (2019) Some aspects of control of freshwater invasive species. Pages 569-602 in: W.J. Sutherland, L.V. Dicks, N. Ockendon, S.O. Petrovan & R.K. Smith (eds) What Works in Conservation 2019. Open Book Publishers, Cambridge, UK.

Where has this evidence come from?

List of journals searched by synopsis

All the journals searched for all synopses

Control of Freshwater Invasive Species

This Action forms part of the Action Synopsis:

Control of Freshwater Invasive Species
Control of Freshwater Invasive Species

Control of Freshwater Invasive Species - Published 2017

Control of Freshwater Invasive Species Synopsis

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