Dairy farmers in particular stand to benefit from the new brand, because they are often the worst affected by docks in their established perennial pasture paddocks.

Nufarm technical specialist Paul Addison says Dockstar herbicide contains 390 gram per litre asulam sodium salt as a soluble

concentrate (SC). It is an easy to use liquid formulation presented in 20 litre packs with a handy dual pourer.

Best applied in spring to established perennial pastures, prior to the emergence of the dock’s flowering stem, Dockstar is a cost effective solution to what can be an expensive weed in terms of lost grazing.

“The feedback so far from customers has been that because it doesn’t knock the grasses around as much as other options it’s

a more favourable option,” Addison says.

“There’s a lot of focus on maintaining pasture yield and quality this season as farmers look for ways to pare back their operating costs and stay within budget.

“Weeds like dock add nothing to overall pasture productivity in the best of seasons; when the pressure is on financially, no-one

wants to sacrifice good grazing if they can avoid it.”

Dock (Rumex sp.) is a prevalent pasture weed throughout NZ. The broadleaf dock is a perennial plant with a large tap-root which can quickly out-compete surrounding pasture.

Broad flat leaves (up to 35 cm long by 15 cm wide) make the weed particularly effective at reducing pasture quality.

Dock foliage contains tannins, and while sheep will generally eat the leaves, cows find them unpalatable, so this weed can become problematic on dairy farms.

A single plant can produce up to 40,000 seeds every year, and these can remain viable for several years leading to the buildup

of a heavy seed burden in the soil over time. Docks spread mainly by seed but plants also regenerate readily from root fragments.

Addison says because they are persistent and tough to eradicate once they become established in a paddock, docks are a real issue for farmers in many parts of the country.

Docks can tolerate poorly drained soil and will often be found in low-lying areas of a paddock. Flowering typically occurs from November to April and controlled is best achieved when the plant is actively growing and in full leaf stage.

 

Published research indicates that while some suppression of pasture growth after Dockstar application occurs, losses in pasture

dry matter are significantly lower than those incurred with the use of traditional thifensulfuron-methyl formulations which to date have been one of the most popular dock herbicides.

“Trials show Dockstar is just as effective at controlling docks as other options on the market (i.e, thifensulfuron).”

Paul Addison says control is relatively slow with peak control occurring two to three months following treatment. Very large, well established docks may require a follow up application.

Application rates are 3.1 to 4.1 litres per ha.

Farmers should use the high rate on heavy infestations of mature docks. As well as established pasture, Dockstar can also be used in red clover, established lucerne and other fruit and vegetable crops. It is not suitable for use on brome, browntop or prairie grass based pastures.

To get the best out of their Dockstar applications, Paul Addison recommends farmers wait for at least two to three weeks pasture

growth after grazing before spraying. This ensures there is sufficient leaf area on the plants for good uptake of the herbicide, and

also minimises any pasture growth check.

“It’s also a good idea to leave at least seven days, and preferably two to three weeks, between spraying Dockstar, and grazing the sprayed paddock.

“Dockstar has no grazing withholding period but this time delay ensures maximum chemical translocation through the plant tissues, and maximum efficacy."