Insects of Southern Australian Broadacre Farming Systems - Grains ...

Acarina: Erythraeidae
Balaustium mite (Balaustium medicagoense)
Distinguishing characteristics/description
adult
‘Pad’-like
structure
on forelegs
10 mm 20 30
Body covered
in short
stout hairs
Rounded body
shape. Body colour
variable but generally
dark red-brown.
Slow moving
Damage
symptoms:
cupping and
leathering
of canola
cotyledons
Nymphs are smaller
than adults and
bright orange-red in
colour with six legs in
the larval stage
Damage symptoms:
bleached leaves leading to
wilting and irregular white
spotting to cereals
and grasses
Insects of Southern Australian Broadacre Farming Systems Identification Manual and Education Resource © 2012
Confused with/similar to
Balaustium mites can be confused with other mite
species. Adult Balaustium mites are approximately twice
the size of adult redlegged earth mites and blue oat
mites, and their body is larger and more rounded than
Bryobia mites.
Distribution, pest status and risk period
Balaustium mites are broadly distributed across the
southern coastal regions of Australia. They are found
throughout most of Victoria, along the eastern side of
New South Wales, in the south-east of South Australia and
the south-west of Western Australia. Balaustium mites are
typically active from March to November, although mites
can persist on green feed during summer if available.
Crops are most at risk during the seedling stage. Summer
eggs hatch in autumn following significant rainfall.
Management options
Biological Cultural Chemical
Unknown.
Ute Guides, Southern (p. 101)/ Western (p. 78).
78
SECTION 4 COMMON Pest, Beneficial and exotic Species
Control of summer weeds can prevent
build up of mite populations.
Avoid volunteer grasses within susceptible
crops, such as cereals and pulses.
Crops attacked/host range
Balaustium mites have a wide host range and are
commonly found attacking canola, lupin and cereal
crops. They will also feed on pasture legumes, lucerne,
grasses and some broadleaf weeds.
Damage symptoms
Balaustium mite feeding causes leaves to become
bleached, which can lead to wilting and plant mortality
under high infestations. Feeding results in the ‘cupping’
and ‘leathering’ of canola cotyledons and irregular white
spotting on cereals and grasses.
Monitoring/sampling
Monitor susceptible crops and pastures in autumn,
particularly those with a history of chemical applications
for redlegged earth mites. Established pastures can
tolerate moderate numbers of Balaustium mites without
sustaining significant damage but seedlings can be
totally wiped out. Balaustium mites tend to be more
active during the warmer parts of the day, so monitoring
in the early afternoon is best.
No chemicals currently registered.
Balaustium mites have a high natural
tolerance to many chemicals.