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

Confused with/similar to
Larvae are similar to those of false wireworms
(Tenebrionidae) but are flatter in appearance and can
grow larger. The predatory larvae of carabid beetles
(Carabidae) are also easily misidentified as wireworms
and may be found in similar environments.
Distribution, pest status and risk period
True wireworms are more common on wetter soils and
are found under plant debris and in the soil. They can
be found together with false wireworms and, when this
occurs, true wireworms are usually more numerous than
false wireworms in some regions.
Larvae are soil-dwelling pests that can be very damaging
to cereals during crop emergence. This is rarely the case
in WA and sporadic in other southern states.
Crops attacked/host range
Germinating cereals are most at risk. Crops following
long term pasture (fallow for 4-5 years) as well as crops
sown on recently cultivated land are more susceptible.
Stubble retention and trash can also favour these pests.
Damage symptoms
Larvae feed on seed and bore into the underground
stems of cereal plants. They may also damage the roots
of seedlings. Germinating seedlings can be ring-barked
and hypocotyls severed just below the soil surface.
Plants wither and die after emergence and damage can
result in a thinned crop or bare patches, which become
visible shortly after crop emergence.
Monitoring/sampling
Check under stubble prior to sowing, especially if
coming out of long term pasture.
Early identification and detection of these pests prior
to seeding and applying a treatment at seeding will
prevent additional costs of re-sowing damaged areas.
As a threshold guide, around 10 larvae/m 2 may
warrant control. Average densities of approximately
40 larvae/m 2 can cause enough damage to necessitate
re-sowing.
Management options
Biological Cultural Chemical
Carabid beetle larvae feed on
soil-dwelling insects, including
wireworms, but are usually not in
high enough numbers to effectively
control large pest populations.
There are no other known parasites,
predators or pathogens that
effectively control wireworms in
cereal crops.
Southern Ute Guide (p. 60).
Removing excess stubble and
trash is an effective strategy where
this resident pest is a problem in
continuous years.
Re-sow affected areas using a higher
seeding rate.
Using a re-sowing method that
disturbs the soil surface, leaving
larvae vulnerable to predation, is
recommended.
Insecticidal seed dressings may offer
some protection from moderate
larval numbers.
SECTION 4 COMMON Pest, Beneficial AND EXOTIC Species
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Insects of Southern Australian Broadacre Farming Systems Identification Manual and Education Resource © 2012