Doretta
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FliesResidents are already reporting major fly infestations. Please let us know if you have been experiencing real problems either with fly or maggot infestations.
The following may be of interest:
Advice about Flies
Flies
Flying insects, especially flies, carry disease - producing organisms known as pathogens. Flies especially are filthy creatures. They tend to feed on excrement, decaying food, dead bodies and other disgusting substances. Whenever they land or feed on these potentially disease-ridden areas, pathogens are transferred onto their numerous body hairs or are ingested into the gut.
Flies cannot eat solid food, so to soften it up they regurgitate digestive juices and their stomach contents onto the food substance. They then stamp the vomit in to form a liquid, usually stamping in a few germs for good measure. This "liquid" is then drawn up by the suctorial mouthparts and in so doing the insects pick up pathogenic organisms, which may collect on their bodies to be transferred on contact with other surfaces or survive passage through the gut to be deposited as fly spots.
Fly spotting, which is produced when the insect feeds or defecates, may result in rejection of contaminated farm produce, for example, eggs, at point of sale.
Diseases
More people actually die from diseases passed on by flies such as diarrhoea and dysentery, than by the more exotic and feared diseases such as malaria.
Flies are so numerous and breed so quickly that they pose a clear hazard to health, particularly in the food industry. The general abundance of rotting matter means they will have no difficulty in finding outside sites on which to lay hundreds of eggs. Once hatched from the eggs the fly larvae feast on protein-rich garbage. Three to five days later they crawl to a cool place and pupate. After another 3-5 days the adult emerges. Within three days this adult fly will repeat the whole cycle again.
If all the descendants of a single pair of flies lived to breed under most favourable conditions they would number a staggering 191 trillion after 6 months. Fortunately many fall prey to spiders, wasps and gnats or succumb to extremes of heat and cold.
Common Houseflies
Common houseflies (Musca domestica) are ubiquitous insects with a flight range of at least 5 miles (8Km). They are highly active indoors. In colder climates breeding generally ceases before winter, whereupon the insects overwinter as pupae or adults. However, in warm environments houseflies remain active and reproduce throughout the year.
Houseflies can transmit intestinal worms, or their eggs, and are potential vectors of diseases such as tuberculosis. They will frequent and feed indiscriminately on any liquefiable solid food which may equally be moist, putrefying material or food stored for human consumption.
Blowflies
Blowflies (Bluebottles, Greenbottles, Fleshflies) are primarily scavengers, depositing their eggs on fish, meat, decaying matter of animal origin and wounds of animals and man. In the absence of more favourable sites they will lay their eggs on animal faeces and decaying vegetable matter.
Blowflies are attracted to rotting animal remains on which they lay their eggs. In their search they can mistake stored meat as a suitable "host".
The possibility of disease spread is similar to the housefly.
Control
Treatment consists of finding the source of the infestation and, where possible, removing it. The application of a residual insecticide may also be indicated, however, attention to hygiene and good housekeeping is the key to controlling this pest.
Fruit Flies
The adult fruit flies are small, yellowish/brown in colour with a darkly striped abdomen. The prominent compound eyes are generally red in colour although darker variants occur. The wings have two clear notches in the front border which can be clearly seen with a hand lens.
Biology
The eggs are white and 0.5-1mm long. Each female lays between 400-900 eggs in batches of 15-25. The egg hatches within 24-30 hours.
The larvae that emerge feed on decaying organic material and larval life is between 5 and 6 days.
Pupation occurs out of the feeding medium and lasts 2-5 days.
The life cycle is rapid in warm conditions with development from egg to adult taking less than two weeks.
Significance
Fruit flies are a source of annoyance in many kitchens, restaurants, public houses, etc. Attraction to alcohol and waste fruit means they are frequently found in such areas and can build up to very large numbers.
These flies are harmless to man and do not bite.
Outbreaks of infestation are often indicative of less than adequate hygiene or drainage problems.
Control
Treatment is similar to that of blowflies. A residual insecticide containing synthetic pyrethroids should prove effective in controlling emergent flies.
Cluster Flies
In spring and autumn several species of fly may be found in large numbers in houses, causing annoyance to the occupants. Cluster flies enter houses during the autumn for hibernation and remain until spring the following year.
Cluster flies include the Cluster Fly (Pollenia rudis); Autumn Fly ( Musca autumnalis) and the Green Cluster Fly (Dasyphora cyanella).
In autumn the flies of all 3 species tend to collect on the outside of buildings, especially on sunny walls and later find their way inside to form clusters of many thousands in roof spaces, under tiles, in soffits, etc.
One house in a terrace/row, apparently indistinguishable from its' neighbours, may attract hibernating flies for many years in succession.
Isolated homes or buildings in the country are frequently infested. Homes in the countryside whose exterior is painted white or another pastel shade appear to attract infestations of cluster flies but there is no hard evidence to support this.
In the majority of cases Cluster Fly infestations go undetected. Infestations are, in the main, encountered by workmen who enter roof spaces during the course of their work or by the occupants when retrieving Christmas decorations.
In spring when the flies become active before dispersal, they can cause a lot of trouble by swarming inside premises. In intermittently heated buildings they may also swarm during the winter.
Biology
Little is known in detail of the life cycle Cluster Flies. The Cluster Fly (Pollenia rudis) is parasitic in earthworms. The Autumn Fly breeds in cow dung. The female Cluster Fly lays her eggs at the entrance to earthworm burrows.
The larvae hatch and find the earthworm and develop within it.
They leave the earthworm to pupate and after pupation the adult flies emerge.
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