Monday, 11 March 2013

Getting the best dock control in grassland

Controlling docks in grassland is important to maintain forage quality and livestock output, but herbicide choice is limited.  Squire Ultra is one of the few herbicides recommended in grassland, particularly in grass with a clover component.  Its use can prolong the productive life of both permanent and rotational grassland, but it is important to get application right in order to get the best results.

Stuart Sutherland, Business Development Manager for Interfarm UK points out that docks are the most economically damaging weeds in grassland.  “They compete directly with grass, reducing yield and effective pasture life as well as affecting the forage quality.  Docks are very competitive weeds with large tap roots that allow survival over the winter period and rapid early spring growth.  They are a real challenge to control successfully.”

“Based on amidosulfuron, Squire Ultra controls broad and curled-leaf docks and other annual broad-leaved weeds, including cleavers, charlock, Shepherd’s purse and field forget-me-not, in both rotational and permanent grassland.  It is fully systemic and, although slower acting than many other traditional dock herbicides, it moves throughout the weed, even into the roots.  But correct timing is key to its success - not too early and not too late.”

“Optimum application for dock control is when there is downward systemic activity in the weed, thus making sure the herbicide gets to where it needs to be, utilising the weeds own translocation system, and also giving it time to work effectively.  In the spring, when docks start growing, there is an upward movement of nutrients from roots to shoots.  Then the weed is at “dinner plate size” the flow reverses to transport feed back to the root system. When the flower stalk starts to grow, the systemic flow reverses again to an upward direction to feed to emerging flower stalk.  Squire Ultra is best applied when docks have large horizontal “dinner-plate” sized rosettes.  At this stage nutrients will be moving downwards from the leaves to the roots and so the herbicide will be taken into the roots.  Soil moisture is also important,” explains Stuart.

Stuart warns that applied too early, when the weeds are using stored tap root reserves to develop new leaves and the nutrient flow is upwards, the herbicide is not moving to where it needs to be and application should be delayed.  Applying it too late when the docks have seed heads and overlapping leaves, weeds will be moving root reserves upwards to develop seed heads.  Here it is best to cut the docks and treat regrowth when appropriate.

Stuart Sutherland points out that Squire Ultra does not affect white clover and can be applied to seedlings from the one or two trifoliate leaf stage onwards, with absolute crop safety.  “Other products control docks but wipe out the clover,” he points out.

“Squire Ultra can knock back docks well, but may not wipe them out completely in just one application, unsurprisingly when you consider how large the root system is and the often variable weed sizes in any one field.  But used in a planned way over time, it will give good results with no crop safety or following crop problems, which is a real advantage in grassland,” he says.

Squire Ultra contains 75% amidosulfuron formulated as Water Dispersible Granule and is packed in a 240 grams pack.  It is recommended on grassland for the control of docks, cleavers, charlock, Shepherd’s purse and field forget-me-not at a dose rate of 60 g/ha.  Squire Utra should be used when docks are at a suitable growth stage between the 1st of February and the 30th June in rotational grass and between the 1st February and the 15th October on permanent grass.  It has no LERAP and is safe to white clover.  Keep livestock out of treated areas for at least 7 days after treatment and until foliage of any poisonous weed such as ragwort has died and become unpalatable.  Do not cut for hay or silage for at least 21 days following treatment.