Killer fly controls aphids

The killer fly Coenosia attenuata lies in wait for its prey on a leaf. It grabs the insects as they fly past and returns to its lookout where, undisturbed, it begins to suck at its victim and tear out and eat the jelly-like muscle tissue with its fangs.

Killer flies are something new in biological pest control. They hunt down their prey—such as garden aphid pests—on the wing. Dr Stefan Kühne of the German Biological Control Institute (BBA) near Berlin, has researched the biology of these useful insects, developed a process for breeding them and hopes now to introduce them into practical use.
    "The term ‘killer fly’, or ‘killerfliege’ in German, was the best name for the ‘scoundrel’" says Dr Kühne. "The Latin name Coenosia attenuata is too long and too musical for an insect that grabs its prey in flight, tears it apart in the air with its dagger like tooth, and then sucks it dry on landing."
    Killer flies are particularly suitable for the biological control of certain insect pests, consuming three to four victims per day. Two to three killer flies per m2 of glasshouse will keep insect pests under control, so long as their numbers have not increased too dramatically, says Dr Kühne. The fly species, which is native to Germany, lives in damp meadows and can therefore overwinter well in glasshouses.
    Adult flies feed on other flying insects; their larvae however feed on insect larvae in the soil. These in turn feed on fungi in the ground. In order to breed the flies, there must be sufficient fungi and sufficient larvae in the ground. The breeding method has proved so successful that a private company intends to mass produce them and they should be on the market before the end of 1996.
    The success of killer flies in the greenhouse has not only been tested by the BBA but also in gardening businesses in Baden Wurtenberg. Stefan Kühne is certain that they will be a major success. It should be pointed out that they are totally harmless to humans! Killer flies can even be used in the kitchen to control fruit flies, according to Dr Kühne. Fruit flies are also pests in pig sties, where the killer fly is also being tested as a method of biological pest control.

BBA, Messeweg 11-12, 38104 Braunschweig, Germany.