Best kills on blackberry are achieved with high volume spraying using a professional handgun sprayer.
Grazon* Extra and Gusto herbicides are also very effective to kill broadleaf weeds including, ragwort & thistles. Grazon* Extra and Gusto are have little impact on established pasture grasses. This is an important benefit as the ground is not bared out as would be the case if using glyphosate based products.Bare ground following a spray application invites regrowth and the establishment other problem weeds such as thistles.
Best results are achieved when Grazon* Exta and Gusto herbicides are applied from late spring to autumn when blackberry bushes are actively growing.
Blackberry needs to be actively growing for these herbicides to have optimum effect. If bushes have been grazed, slashed, bulldozed,burnt, or on areas which have previously been treated with a herbicide, delay treatment until regrowth has had time to grow to approximately 1 metre.
One application may give satisfactory control but subsequent re-growth and seedlings should be re-sprayed after hardening off. Do not use this product under extremely dry conditions or when blackberries are stressed as considerable re-growth may occur.
Mixing Rate
To control blackberry using either Grazon* Extra or Gusto herbicides, mix the chosen herbicide at rates of 350 or 500mL per 100L of water. Use the higher rate on plants that have been damaged by grazing stock or insects or on blackberries that are known to be difficult to kill.
Application & Coverage using a high volume handgun
Thorough coverage of blackberry foliage to the point of run-off is essential, however avoid excess spraying which is wasteful of chemical.
Apply a spray volume of 3000 to 4000L per infested hectare of 1 to 2m high blackberry ( this equates to 30 to 40L per 100 square metres).
Application & coverage using a knapsack
Apply the recommended spray mix to give full coverage of leaves and stems. The final volume of application should be similar to hand gun application ie A spray volume of 3 to 4L per 10 square metres should be used.
Note that knapsack sprayers do not have the pressure of high volume handguns so penetration and coverage will not be as effective. Poor coverage and penetration may result in excessive regrowth.
The Grazon* Extra label states that knapsack application is only recommended for the control of herbaceous weeds,
such as capeweed, fireweed and spear thistle, and woody weeds that are not regrowth and less than 60 cm.
Use of marking dyes
A marking agent can be used to check spray coverage and identify sprayed areas to avoid double treatment
Read the product label
It is important to read the product label before using any agricultural chemical. The product label and Directions For Use booklet are attached to every container. The labels and associated booklets contain directions for use and other important practical information relating product use along with personal and environmental safety directions.
Please note that the information above is general in nature and
does not constitute advice nor recommendation. You personally are responsible
to read the product labels to determine suitabilty and appropriate use patterns
for your situation.
* Grazon is a registered trade mark of Dow Agrosciences