Tiny flies around the fruit bowl. Tiny flies around the recycling bin. Tiny flies around the kitchen sink. Tiny flies around beer pumps, drip trays and bottle storage.
You may have cleaned everything you can think of and they are still there. Or a pub, bar or restaurant may be seeing increasing numbers around the service area.
The flies you can see are usually the symptom. The problem is where they are breeding.
Tell us what you have noticed. We will explain the most sensible next step. Prices are plus VAT.
What have you noticed?
Common signs include:
- Tiny flies around fruit bowls, recycling bins or kitchen sinks
- Flies around beer pumps, drip trays, bottle stores or floor drains
- Activity in food preparation or bar areas despite repeated cleaning
- Small flies resting on walls, windows, equipment or nearby surfaces
Many people think the flies have appeared from nowhere. They are usually breeding close by.
The small fruit flies normally found indoors are Drosophila species, often called vinegar flies or beer flies. They are usually small and yellowish brown, and many have prominent red eyes. They are associated with fermenting fruit and vegetables, sour milk, beer, vinegar and sugary residues.
Not every tiny fly is a fruit fly. Drain flies look fuzzy and moth-like and breed in wet organic deposits and drain biofilm. Phorid flies have a distinctive humped back and are associated with decaying organic material. Flies mainly around damp houseplant compost may be fungus gnats.
If the flies appear to be drain flies, phorid flies or fungus gnats, we will explain the likely source and the most sensible next step. Some problems require cleaning, drainage investigation or repair as well as pest control.
Why is it happening?
Fruit flies need suitable breeding material. In a home this may be overripe fruit, forgotten produce, recycling, food waste, damp cloths or a small spill. In a pub or commercial kitchen it may be beer residues, sugary drinks, drip trays, bottle storage, waste, floor drains or a void that routine cleaning does not reach.
Fruit flies can arrive with fruit and vegetables as eggs or larvae. Their presence does not automatically mean a property is dirty, but numbers can increase quickly when suitable fermenting material is available.
Even a small amount of fermenting residue can provide a breeding source.
Fruit flies develop through egg, larva, pupa and adult stages. In warm conditions, a new generation can develop in as little as about a week, although it takes longer at lower temperatures. Mature larvae leave the wet breeding material and move into nearby drier corners or crevices to pupate. This is why adult flies may continue appearing after the obvious breeding source has been removed.
Finding the breeding source
If you have not found the cause, you have not found the cure.
The important part of the job is finding where the flies are breeding, rather than repeatedly killing the adults on windows and surfaces.
A proper inspection may mean using a torch, getting down to floor level and looking at places that routine cleaning misses. This can include the underside of equipment, drip lines, the lip of a drain, recycling crates, bottle storage and spills beneath bars or kitchen units.
How Guardian approaches a fruit fly problem
Inspection
We look at the type of fly, the pattern of activity and the areas most likely to contain breeding material. This can include bars, drip trays, recycling, drains, appliance voids, waste and food or drink residues.
Source removal
Once the source is found, it must be removed or thoroughly cleaned. We will explain what needs to be done and whether any further pest control measures are worthwhile.
Other measures
Traps and insect light traps can monitor activity and reduce adult numbers. An insecticide may also be used where appropriate. None of these measures removes the breeding source, so if fermenting material remains, more flies will continue to emerge.
What happens when we visit?
The visit begins with identifying the fly as far as reasonably possible and inspecting the likely breeding areas. We look at food and drink sources, waste, drains, hidden residues and the cleaning routine.
We explain what we have found, what needs to be removed or cleaned and whether any treatment, monitoring or further investigation is appropriate. Where suitable, measures may be used to reduce the adult flies while the source is being dealt with.
After the visit, domestic customers and one-off commercial customers receive an electronic report. Planned commercial customers receive electronic visit reports and the agreed site records.
Will one visit be enough?
If the breeding source is found and removed, one visit may be enough. Activity may not stop immediately because existing adults and pupae can remain.
If the source is inaccessible, more than one breeding site is present, or cleaning and repairs are still needed, further work may be required.
We do not guarantee that fruit flies will never return.
Commercial considerations
The most common commercial problems occur in pubs, bars, restaurants, cafes, hotels and food premises. Fruit flies around a bar, service area or food preparation area can quickly become a customer, hygiene and audit concern.
The inspection may include beer pumps, drip trays, bottle storage, soft drink equipment, waste areas, drains, floor edges, cleaning equipment and spaces beneath fixed equipment.
Commercial work can normally be discussed over the phone. We will explain whether the information provided is enough to arrange the work or whether the site needs to be inspected first. Prices are plus VAT.
Frequently asked questions
Why do fruit flies keep coming back?
Usually because breeding material remains or there is more than one source. Adult flies and pupae may also remain after the obvious source has been removed.
Will an insect light trap solve the problem?
It can monitor activity and reduce adult numbers, but it will not remove the breeding source.
Are fruit flies always caused by fruit?
No. Beer, wine, sugary drinks, sour milk, food waste, recycling, damp cleaning materials and organic deposits around drains can all provide suitable breeding material.
Can a very small spill cause a large problem?
Yes. Even a small amount of fermenting residue can provide a breeding source, particularly in a warm area that is rarely disturbed.
Can fruit flies breed in drains?
They can breed in organic residues in and around drains. Drain flies and phorid flies use wet organic material in different ways, so correct identification matters.
Are fruit flies a health risk?
In a home they are mainly a nuisance, but they should not be allowed around uncovered food or food contact surfaces. In food premises their presence is a hygiene and contamination concern.
Tell us what you have noticed
Tell us where the flies are, whether the problem is at a home or a business, whether they are around food or drink, how long it has been happening and whether you have found a possible source. Photographs can help.
You do not need to identify the fly before contacting us. We will explain the most sensible next step.
