i) Herbicide use for weeds

Herbicides can play an important role in the control of environmental weeds, particularly if used in conjunction with non-chemical approaches (above). Several application techniques are available and these are described below:

Spraying
Spot-spraying or spraying a broad area of infestation is an effective tool against weeds. But make sure you don’t wipe out the vegetation you want to keep as well. Bear in mind the impacts of broad scale herbicide application on wildlife, birds and water quality.

Cut and paint
This involves cutting the weed tree with a bush-saw or chainsaw, and applying herbicide to the stump. The herbicide must be applied immediately, but need not be painted over the whole stump area — just to the outside edge or ‘cambium layer’ of the tree, so that it can be immediately translocated down to the roots.

Stem injection
The herbicide can be injected into the stem of the weed tree.

Frilling
Frilling involves cutting small notches around the trunk of the weed tree, into which herbicide is applied.

Stem-painting
The same principles as ‘cut and paint’ can be used on vines and smaller weed plants.