Blackberry control manual - Weeds Australia

• Infestations where other management options
are not suitable. Use of the leaf rust fungus
is most appropriate where it is not economic
or feasible to use other methods of control
such as herbicides or mechanical removal.
Infestations that are difficult to access or
where sensitive native species are present are
examples of where biological control may be a
good option.
Other natural enemies of blackberry
There are several known natural enemies
of blackberry present in Australia that have
not been deliberately released as biological
control agents but can add additional stress to
blackberry plants.
Red berry disease mite (Acalitus essigi)
This mite causes ‘red berry disease’ in cultivated
and weedy blackberry species in Australia and
other parts of the world, including Europe, North
America, Chile and New Zealand. Fruits infested
by the mites do not ripen; that is, they remain
red instead of maturing and turning black.
The mite has potential value as a biological
control agent because it attacks a wide range of
blackberry species, including species that are
resistant to the European blackberry leaf rust
fungus. However, it does not damage the rest of
the plant, so it can be considered as an option
only for preventing the spread of the weed.
It may also be useful in the management of
commercial varieties of raspberry or blackberry
that are escaping from orchards and becoming
naturalised.
Although the mite can affect commercial
blackberry operations, it appears to have limited
dispersal once established, and routine chemical
treatments appear to be effective in its control.
Continued research on the potential of the mite
as a biological control agent is needed before
active distribution can be contemplated.
Kuehneola uredinis
Kuehneola uredinis is another rust that can
produce small powdery pustules on the lower
surface of leaves. It differs from P. violaceum in
that the pustules on the leaves are only pinpoint
sized, are more orange, and do not produce the
corresponding purple blotch on the upper leaf
surface. This rust tends to attack the older leaves
of blackberry in late summer and autumn but can
also cause large, powdery, orange pustules up to
one centimetre long that break through the bark
of the second-year canes.
K. uredinis on the top side of a leaf.
Paul Yeoh (CSIRO Entomology)
CSIRO Entomology
Paul Yeoh (CSIRO Entomology)
Red berry disease on R. laudatus.
Blackberry leaf rust fungus (P. violaceum) on leaves and
the floricane.
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