Calliphora spp.: Bluebottle flies.

General Description: Large flies, 12 mm. Long metallic blue in colour, with stout bodies. Larvae similar to those of Lucilia but larger.

Life Cycle: General blowfly life cycle.

Location: Areas of skin with constant moisture, eg. The breech and tail areas can become affected after a primary strike by Licilia. Open wounds, eg. from castration, tail docking, or parasite worry may also become infested. Prolonged wet weather may promote myiasis of the back.

Geographical Distribution: Australia, England, North America.

Significance: Calliphora blowflies may weaken and kill sheep. They with the other genera of blowflies are the most serious pest of sheep in Australia.

Effect on Host: Blowflies cause extensive lesions with bacterial infection. Death is possible Larvae feed on damaged skin that is originally disrupted by a primary strike by Lucilia flies. Myiasis develops and expansion of the lesion produces a large wound in which bacteria multiply. Lack of feeding by sheep weakens them, and death may occur from bacterial toxins in the host's blood. Depression, loss of appetite, stamping of legs, and jerking of the tail are characteristic signs in addition to the foul-smelling, expanding areas of loose skin under discoloured wool.

Diagnostic Information: Presence of larvae in wounds.

Control: Spraying or dipping of sheep with insecticide preparations every 4 weeks may protect against blowfly strikes. In Australia a localised high-pressure application of insecticide, known as "jetting" is used. Resistance of Calliphora to numerous insecticides has been reported. Barns and other areas where sheep are kept should also be treated with insecticides. Crutching (shearing the breech area) and the Mules' operation is very helpful in preventing myiasis.

Calliphora – adult