Dock

Do

• Plan your control program, this will save time and money in the long-run;
• Consider the impact of your control methods on off-target species, especially if herbicides are used;
• Ensure machinery and equipment is washed down between sites or prior to contractors leaving site;
• Get in early - for new infestations, eradicate before the plants reach the flowering stage: once plants begin seeding, control becomes more difficult and expensive; and
• Carefully time your use of herbicide for best results (see Herbicides for docks control for more information);
• Coordinate your control program with neighbouring landholders where your weed problem crosses property boundaries;
• Revisit and regularly inspect the site and ensure follow-up is undertaken;
• Use a combination of different control methods; and
• Establish vigorous pasture (or native species) after removal to reduce re-infestation.

Don't

• Don't introduce dock to dock-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 allow dock to flower and set seed before treatment;
• Don't rely on one attempt at removal - follow-up is essential; and
• Don't rely on just one control method.

Spread of dock

• Docks spread mainly by seed. Most dock seed falls close to the parent. Soil movement may also distribute seeds.
• Damage to the root system can create root fragments which can be spread by cultivation, allowing new plants to form from each fragment.
• 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 docks.

Physical removal and cultivation

• Hoeing or digging can be used to remove docks, provided the entire tap root is removed.
• Seedlings and young rosette docks can be killed by cultivation. However, old docks with well developed tap roots will often survive cultivation, especially in autumn or winter.
• Docks regenerate readily from root fragments and will often survive a single cultivation. Repeated cultivations may be necessary to eradicate docks.

Grazing

• Vigorous well managed pasture helps prevent dock establishment.
• Avoid over and under-grazing. Block grazing is strongly recommended.
• In dairy pastures, winter grazing should be controlled to prevent pugging of the soil.
• Attention to drainage of pasture areas which get waterlogged or lie wet for extended periods will reduce the potential for dock invasion.

Biological control

• Biological control is the use of a living species, usually an insect, mite or disease, to control a weed;
• Biological control will not eradicate docks, but can be used in conjunction with other control methods;
• Biological control agents that have been released in Tasmania include the clear wing dock moth.
• For more information on biological control programs in Tasmania contact the Tasmanian Institute of Agriculture

Chemical control

• A number of herbicides are registered for use on docks in Tasmania. See Herbicides for Dock Control for more information.
• In newly-sown pasture, seedling docks are best controlled with MCPA sodium at 250g a.c./ha (1.0 L/ha of a 250 g/L formulation). MCPA will damage clover and must not be applied until young clover plants have 2-3 trifoliate leaves, and the grass seedlings are 100 mm.
• MCPA or 2,4-D amine can be used to control small and medium sized docks in established pastures. More effective control can be obtained by adding dicamba to the MCPA or 2,4-D solution where clover damage is not a concern.
• For control of large docks, asulam, 2,4-D ester, or metsulfuron-methyl are required. Repeat treatments may be necessary. All of these herbicides may severely damage or eliminate clover from the pasture; for up to 12 months in the case of metsulfuron-methyl. Metsulfuron-methyl may also damage ryegrass. Application of a nitrogen based fertiliser may be required to maintain pasture productivity in such situations.
• In turf, dicamba plus 2,4-D plus mecoprop, or dicamba plus MCPA or dicamba plus mecoprop should be used. Treatment should be carried out in early spring (September or early October) when the grass has started to flourish, and may be repeated about 8-12 weeks later. Treatment in autumn, about six weeks after the autumn break should eliminate autumn germinating seedlings. Label recommendations for application rates should be followed.