Column 8 in today’s Sydney Morning Herald stated that Sydneysiders’ kitchens have been infested by fruit flies, stating that, “They emerge from fruit and hang around all summer”. The flies referred to are not fruit flies, they are the very small vinegar or ferment flies (Drosophila). Genuine fruit flies are kept out by fly screens. Vinegar flies emerge from fruit, tomatoes, etc. as grubs (larvae) and require pupation outside the fruit in order to complete their life cycle as a fly. If these tiny pests are a persistent problem, there must be a breeding ground nearby or the kitchen needs more regular cleaning.
Vinegar flies are attracted to the smell of yeast in fermenting organic materials and drains. To eliminate the problem:
- Do not keep fruit at room temperature in warm, humid weather
- Cover compost and garbage containers
- Regularly rinse out garbage containers
- Rinse beer and wine containers before recycling
- and treat drains with an enzyme product to break down thick scum where they can feed and reproduce.
Genuine fruit flies, the Mediterranean Fruit Fly (Ceratitis capitata) and Queensland Fruit Fly (Dacus tryoni) cause a lot of destruction in gardens. They require pupation in soil after the maggots emerge from fruit. To reduce the problem of genuine fruit flies, collect all fallen fruit, put it in a sealed black garbage bag and leave the bag in the sun for three or four days to cook the larvae (and encourage your neighbours to do the same). Never put infected fruit in the compost container.