There are vinegar flies sitting on the ceiling and bulk heads.
Where are they breeding?
What is the difference between vinegar flies and fruit flies? Fruit flies are found around ripening fruit whereas the vinegar fly is found primarily around decaying or overripe fruit and vegetables, baked goods containing yeast, garbage bins, beverage/empty beverage containers such as fruit juices, ciders, soft drinks, beer and wine bottles. Vinegar flies love sugary yeasty substances.
During the day when staff are moving around behind the bar, or other problem areas, the vinegar flies get disturbed and go and sit up high, out of the way. You will see them around light fittings, smoke alarms, air conditioning vents, edges of walls, front edges of shelves, ceilings and bulk heads. You can see where they have been, their preferred spots as they leave the little specks of poo.
When all is quiet again, the vinegar flies return to their preferred place, down low, under the bars areas, congregating around their food source. The sticky, moist, dark areas are usually popular. With warmth possibly generated by refrigerator motors, glass washing machine engines and a sugary sludge to feast on, these little critters are in their element. They can breed alarmingly quickly in the right conditions, in warmer climates and summer months. Their optimal breeding temperature is around 26 degrees Celsius.
Vinegar flies are attracted to other areas in food businesses to. Dirty linen such as the used tablecloths and napkin collection bags, dirty t-towels, bar mats, rubber floor mats, soft drink dispensers nozzles, beer taps and spirit nip pourers, rarely cleaned drains, overflow outlets, tun dishes, damp mops and broom heads. with the organic materials caught in them. In juice bars and fruit and veg shops they like the pineapples, stone fruit, sweet potatoes, bananas, all manner of goodies. One establishment recently has had the vinegar flies breeding in the soil of their indoor pot plants. These plants are on shelves high up near the ceiling, where all the warm air sits - ideal.
So, what to do... to control vinegar flies.
In bar areas, you are best to place the units down low under the bar. Attach them with a zip tie to what ever is available.
Position units so they are dispensing into the trouble spots. Check for tun dishes and where possible, tap these up with masking tape or glad wrap, anything that stops the vinegar flies getting to the liquid sugar sludge.
Some under bar areas are extremely well utilised with not many under bench spaces available. This does make the job tricky. Dispensing pyrethrin into the air, above head height does little to combat vinegar flies. To get on top of them you need to knock them where they feed and breed. Under the bar!
The cleaner and dryer you can keep these under bar areas the better.
Use beer tap brushes in beer taps over night.
Place post mix dispenser heads in a suitable liquid overnight. Using a wine cooler bucket works well.
Wipe over the neck of red wine bottles at close. Red wine is the vinegar flies favourite thing!
For issues such as dirty linen, floor mats, bar runners and mops, where possible, put outside at night. Otherwise store together and position a unit dispensing across the area. Try and store in a small area of no air movement.
Drain cleaners are specially formulated to clean drains and pipes of organic matter, thus removing one potential food source for vinegar flies. I have heard varying reports about them. A clean drain is certainly going to help. Tape over these drains as well if not used in regular cleaning routine.
If you have vinegar flies, gnats or fruit flies in your pot plants, it is recommended you cover the soil surface with a very course sand or aquarium gravel. The flies lay their eggs in topsoil, where the young hatch. The heavy gravel or sand prevents newly hatched larvae from climbing out of the soil. This heavy layer will break the breeding cycle .
Flies are attracted to damp soil. Eggs and larvae present in soil will not survive if the soil is not moist. Keeping your plants drier rather than moister will help. Empty any excess water in the pot plants under tray.