Compost (‘Vinegar’) Flies

Spring has sprung, and the compost bins are warming up, encouraging romance among the vinegar flies, known to many of us as ‘compost flies’.

These little black flies – somewhat smaller than a match head – are harmless to humans, and only become annoying when they find their way into the house in large numbers, hanging about whatever fruit is going off, especially lemons and other citrus.

It seems to be impossible to keep the little fellas locked down in the compost bins – even the smallest holes or imperfection in the lid seal allows them to wander in and out, much to the joy of Willie-Wagtails and New Holland Honeyeaters, who hang about on the bin lid and dance into the air for a quick snack ‘on the wing’.

At the height of the breeding season, every trip to the Gedye Bin results in a face-full of vinegar flies when the lid is opened.

We slow the little blighters down by throwing in a few shovelfuls of soil, then laying branches of wormwood over this to discourage them further from their rotting lunch of mouldy lemons, which choose this time of year to rain down in abundance.

Wormwood is a pretty – if somewhat smelly – soft silvery-green bush traditionally grown around fowl runs in Australia to discourage various ticks and mites from visiting the hens. It’s drought-hardy and makes a robust hedge, and is supposed to discourage other weeds in the vicinity via exudations from its roots.

And does wormwood repel vinegar flies? I don’t really know, but even if it doesn’t save me from a face full of flies, it always looks attractive after a little pruning, and adds some organic matter to the compost bin along the way.

Inside the house, we’ve discovered a sure-way method for sweeping up all the vinegar flies that blacken walls and bench tops; we lay sticky fly traps over small dishes of cider and ‘stout’ beer whose heavenly aroma lures the flies to a sticky death.

Just hanging the sticky fly trap somewhere in the room is a waste of time; the flies ignore it.