Rope Twitch (or English Couch Grass)

(Elytrigia repens)
Rope Twitch, photo: CDFA

What is rope twitch?

  • Rope twitch is a significant weed of crops, pastures and gardens in Tasmania.

How to identify rope twitch

  • Rope twitch is an erect, perennial (long lived) grass with numerous rhizomes (underground-stems). In pastures and mown areas rope twitch sometimes assumes a prostrate (ground hugging) habit and may not produce flowering stems.
  • Rope twitch produces an extensive root system with many rhizomes. The rhizomes are white in colour and may be several metres long. Shoots and roots develop from nodes along the rhizome.
  • The leaves are medium to light green in colour and are finely pointed at the tips. In cross section the leaf forms a flat "V".
  • The flowers consist of spikelets arranged alternately in two rows, one on each side of the stem.
  • For further help in identifying rope twitch, search the Dennis Morris Weeds and Endemic Flora database for rope twitch illustrations. If you are still in doubt about the weed you are dealing with, contact Biosecurity Tasmania on 03 6165 3777 for help.
Rope Twitch, photo: Keir Morse
Image top: Rope twitch, © CDFA.
Image above: Rope twitch grass stem, © Keir Morse.

Rope twitch in Tasmania

  • Rope twitch is not declared in Tasmania.
  • Rope twitch is widespread in agricultural and horticultural areas in Tasmania. In recent years it has become widespread in the intensively cropped areas of the North-West coast. It is also common in parks and recreation areas, and in domestic gardens.
  • Rope Twitch is a serious weed in areas of annual cropping, particularly for crops such as onions. If present at moderate to high densities, rope twitch reduces the yield of all crops, including cereals.
  • Rope Twitch is not normally a problem in vigorous, well managed pasture with adequate water supply. However where pasture vigour declines rope twitch can quickly dominate. In pasture on light textured soils, rope twitch may form dense mats which exclude all other pasture species. Its occasional prostrate (or ground hugging) habit in pasture makes it of little value for grazing.
  • In gardens rope twitch is considered one of the worst weeds in Tasmania. It can infest all areas including herbaceous borders, ornamentals shrub beds, vegetable gardens, potted plants and lawns. If allowed to proliferate unchecked it can become the dominant plant in the garden.
Detailed management and control guidelines for rope twitch can be found in the Rope Twitch Control Guide. Refer also to Herbicides for Rope Twitch Control. For further information see DPIPWE's Weed Links and Resources.


See also
Herbicides for Rope Twitch Control
Weed Links and Resources

Other useful links
Pest Genie
APVMA

Rope Twitch Control Guide

Do

  • Plan your control program, this will save time and money in the long-run;
  • Thoroughly wash down machinery and equipment between sites;
  • Check purchased garden materials for rope twitch before planting;
  • Use a combination of control methods for best results;
  • Follow-up is essential to avoid re-infestation.

Don't

  • Don't introduce rope twitch to rope twitch-free areas (e.g. by failing to wash down machinery and equipment between sites);
  • Don't start your control program without first planning your approach;
  • Don't disturb sprayed rope twitch until there is complete "brown-out".

Spread of rope twitch

  • Rope twitch's spreads mainly by its vigorous rhizomes. The weed can spread quickly through the soil, and an infestation may spread by several metres in one year solely through rhizome growth.
  • Rhizome fragments can quickly give rise to new shoots and roots and establish a new plant. Soil particles adhering to machinery used in infested areas can carry rhizome fragments to other areas.
  • Seed is of limited significance in the spread of rope twitch.

Avoid the introduction of rope twitch

  • Preventing the introduction of rope twitch to rope twitch free areas is the best means of control.
  • Good machinery and equipment hygiene-practices are vital to avoid transporting fragments of rhizome to new areas.
  • Purchased plant material such as potted plants should be carefully checked for rope twitch before the plant is introduced into garden areas.
  • See the Washdown Guidelines for Weed and Disease Control for detailed information on how to wash-down equipment and personnel to reduce the chance of spreading rope twitch.

Weed matting

  • Rope twitch can be suppressed using impervious mulching materials to smother the plant.
  • Commercially available weed matting or black polythene sheeting work well. All holes and other potential areas of escape in the matting or plastic must be sealed.
  • Use weed matting over several months to completely kill the rope twitch. Depending upon the material used, this practice may have a negative impact on beneficial organisms within the soil.
  • Wood chip, bark and similar types of mulch used without a polythene sheet will not control rope twitch as the rhizomes will grow in the mulch rather than the soil.
  • Continual follow up of treated areas is vital. If follow up is not carried out, small regrowths can rapidly develop into large infestations.

Cultivation

  • Cultivation can be used to disrupt the rope twitch rhizome system. Cultivation must reach the whole of the rhizome layer, as rhizomes left below the cultivation depth will rapidly re-infest the soil.
  • Following cultivation the area can be cropped for at least one season. Spot spray regrowth during the cropping rotations. The area can later be sown to permanent pasture.
  • When infestations are light, good results can be achieved by cultivating in autumn, then follow up by fallowing the area through winter, or growing a competitive crop such as oats or annual ryegrass for grazing. This can be followed by an application of glyphosate then sowing spring barley or a wheat crop.
  • Rope twitch rhizomes can also be killed by cultivation and fallowing of infested areas and then exposing the rhizomes to drying out and freezing. However the drying out or freezing of the disturbed rhizomes must last over a long period. Overnight frosts which clear during the morning will not kill the weed.

Chemical control

  • A number of herbicides are registered for use on rope twitch in Tasmania. See Herbicides for Rope Twitch Control for more information.
  • Herbicide treatment should be combined with cultivation and good hygiene for best results.
  • Spray herbicide right up to, and if possible through fence lines, to prevent re-infestation from adjacent areas.
  • When rope twitch is actively growing use glyphosate or fluazifop-p.
  • If the rope twitch is not actively growing, one option is to stimulate growth by irrigating the infested area over a period of a few weeks, then applying the herbicide.
  • Following spraying, the area should not be disturbed until there is complete "brown-out" of all above ground parts.

Herbicides for Rope Twitch Control

Herbicides for Rope Twitch Control



Important Disclaimer
To the extent permitted by law, the Tasmanian Department of Primary Industries, Parks, Water and Environment (including its employees and consultants) excludes all liability to any person for any consequences, including but not limited to all losses, damages, costs, expenses and any other compensation, arising directly or indirectly from using information or material (in part or in whole) contained on this website.

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