Common Green Bottle Fly - Veterinary Importance

Veterinary Importance

Many blowflies have an impact in the veterinary sense, and L. sericata is no exception. In places like the UK and Australia L. sericata is commonly referred to as the "sheep blowfly" since sheep are its primary host. Although it affects mainly sheep, L. sericata is not host-specific.

In northern Europe, the fly will lay its eggs in sheep wool. The larvae will then migrate down the wool where it will feed directly on the skin surface. This can cause massive lesions and secondary bacterial infections. In the UK, it is estimated that blowfly strike affects 1 million sheep as well as 80% of sheep farms each year. This causes a huge economic impact in these regions. Not only does it cost money to treat infected animals, but also, measures must be taken to control L. sericata.

Since this fly tends to lay its eggs in wool, a simple and effective way to reduce the incidence of infection is to shear ewes regularly. Enacting simple sanitary measures can also reduce blowfly strike. Timely and proper disposal of carcasses and proper removal of feces can aid in significantly reducing strike. Moving sheep from warm, humid, and sheltered areas to more open areas can also help to reduce blowfly strike, for this eliminates conditions conducive to fly development. Trapping systems such as sticky paper may also be used to control fly numbers. Treating a flock with chemical agents can be costly but can aid greatly in maintaining the resistance of the flock to L. sericata. Plunge dipping in diazinon can directly kill the fly on contact. This method works from 3 to 8 weeks in controlling the fly. An alternate chemical method is a pyrethroid pour-on, which will last from 6 to 10 weeks depending on the exact type of pyrethroid used. Cryomazine and dicylanil, which are insect growth regulators, are also effective and last from 10 to 16 weeks. Although chemical treatment can be very effective, it is costly, tedious, and takes up valuable time.