Soldier flies, particularly the sugarcane soldier fly Inopus rubriceps (Macquart),
cause sugarcane losses from Innisfail to New South Wales. Recorded losses reached
their highest level in the 1960s. Prior widespread use of organochlorine insecticides
may have stimulated outbreaks by killing natural enemies. Approaches to managing
soldier fly losses can be grouped as strategies to minimise the number of larvae
present at planting, the number of immigrating flies, the increase of larval numbers
in successive generations, and the losses that a given larval population inflict on the
crop. Infestations should be monitored to determine the need for control measures.
An integrated pest management (IPM) program should include timely removal of
infested ratoons, early-season harvest of plough out blocks and destruction of stools
at the surface, bare fallowing for as long as practicable with a cover crop grown only
when needed to protect the soil, intensive working of ground during the flies'
breeding season, tolerant varieties, agronomic conditions that maximise crop tolerance,
and farm management to avoid reinfestation of newly planted crops. Further
work is needed to develop methods of encouraging natural enemies. Treatment with
chemical insecticides or the fungal pathogen Metarhizium anisopliae could be
included in an IPM program subject to satisfactory trial results.