The following points highlight the top three methods used for controlling houseflies. The methods are: 1. Control of Breeding of Houseflies 2. Protection of Food 3. Killing Adult Housefly.
Method # 1. Control of Breeding of Houseflies:
(a) Flies breed in stable manure, human faeces and garbage, these should be kept in closed cisterns, then removed by municipalities and be either buried underground or incinerated, as is done in many cantonment areas.
(b) City and village garbage may be spread out in fields so that it dries quickly to prevent egg-laying. If lime is added to manure it also prevents egg-laying. In China sodium cyanide solution is put in human faeces containers and it prevents eggs-laying successfully.
(c) Garbage and refuse may be treated with insecticides, such as calcium borate which kills the larvae.
Method # 2. Protection of Food:
If kitchens are screened and food is kept covered the flies cannot transmit disease, but this should be done on a large scale in public restaurants, in shops which sell sweets, and especially in keeping a city’s milk supply free from flies.
Method # 3. Killing Adult Housefly:
Many devices can be used for killing flies in a home:
(a) Fly swatters are used on dining tables, fly paper is put on windows and tables to which the flies get stuck and die.
(b) Hang wires smeared with a boiled mixture of four parts of resin and one part of castor oil, the flies sit on these wires and die.
(c) A few drops of 3% solution of formalin in a saucer of sweetened milk is kept in homes and restaurants, flies suck up this milk and die, but the milk should be rendered slightly alkaline to make it palatable to flies.
(d) Flies can be killed most successfully by spraying of houses, barns, and with D.D.T., benzene hexachloride, or chlordane. Large areas of cities and villages can be sprayed from an airplane with two quarts of D.D.T. per acre, and the spraying is repeated at intervals of seven days for 21 days to ensure that all stages of houseflies are killed.
(e) Other chemicals like lethane, pyrethrum, flit, B.H.C., etc., may also be used for killing the flies.