Blackberry control manual - Weeds Australia

Case study
Examples of using herbicides to control
blackberry
Choosing the right type of herbicide and the most
appropriate way to apply it can be difficult. Land
managers should consult their local chemical
advisor for current advice before starting a
herbicide control program, as the decision may be
different depending on the site, the conditions, the
equipment available and the funding available.
The following information gives examples of how
the various registered herbicides in Table 4.1
(p. 45) can be used. This should be used only
as a guide to ask the chemical advisor the most
relevant questions when developing a herbicide
program.
Large, dense infestations
(covering more than one hectare)
••If necessary for access, burn or slash canes in
early winter to early spring.
••Apply metsulfuron-methyl (e.g. Brush-Off®)
according to the label using a site-appropriate
method when there is sufficient regrowth.
••Repeat the application of metsulfuron-methyl
for one or two growing seasons after the initial
application when regrowth is one or two metres
long.
••Once the infestation is reduced to a small area,
apply a picloram + triclopyr–based herbicide
(e.g. Grazon® Extra) according to the label.
••Monitor the site for regrowth and retreat as
necessary.
Natural bushland
••If required, burn or slash canes in late winter to
early spring to gain access.
••Apply a picloram + triclopyr-based herbicide
(e.g. Grazon® Extra) according to the label using a
site-appropriate method.
••If regrowth occurs and trees show symptoms
of being affected (e.g. leaf curl or leaf drop),
treat with triclopyr (e.g. Garlon® 600), otherwise
retreat with Grazon® Extra.
••Monitor the site and treat regrowth as necessary.
Sensitive areas
Apply a mixture of triclopyr + picloram with diesel
(e.g. Access®) or gel (Vigilant®), using the cut and
paint method. This may lead to suckering a metre
or two from the treated crown; any suckering will
require retreatment in the following season.
Urban areas
Use the recommended rate of glyphosate
(e.g. Roundup®) to spray the foliage and canes
while the blackberry is actively growing.
Often there is very heavy fruit set and the new
growth shows a characteristic ‘witches broom’
appearance. Control is marginal and will need to
be repeated for several years. Grubbing may be
required to achieve eradication.
Small area or individual plants
(covering less than one hectare)
••Apply a picloram + triclopyr based herbicide
according to the label. Cover a two metre area
around the bush to reduce suckering. Refer to
the label for critical comments on withholding
periods if livestock will have access to the site
for grazing.
••Monitor the site and repeat annually until there is
no regrowth occurring.
The ‘witches broom’ effect.
Birgitte Verbeek (NSW DPI)
48