Fly Control on Poultry, Pig and Dairy Farm
Besides being of a great nuisance value, flies are potential carriers of disease and can play a major role in the economics of a farming enterprise. It is important to understand the life cycle of the fly in order to implement any control measures.
LIFE CYCLE OF THE FLY
The stages of the life cycle of the fly are egg, larva, pupa and adult. The eggs are deposited by a mated female 4 – 8 days after copulation. The eggs are laid by the adult fly in manure and decaying matter. Flies have the ability to lay very large quantities of eggs at a time (+/-120eggs). A female fly deposit about 4 – 6 batches of eggs in her life time. They eggs are small white elliptical eggs about 1mm in size.
The eggs will hatch approximately 24 hours after deposition, but this can vary depending on temperature.
Larvae (maggots) hatch out of the eggs. The larva molts twice so that there are three larval stages with each stage being larger than the last.
First stage larvae are light sensitive, especially the first stage larvae and move downwards in the breeding site, the third stage larvae react more positively to light and move to lighter drier areas to begin pupation. The time from larval stage to pupa varies between 4 days at high temperatures (35 ) to 25 days at 16 c.
Pupas are a reddish brown color and darken to a dark brown color. They are about 6 mm long and oval in shape. Pupa may remain in this stage for long periods and emerge as flies under favorable climatic conditions i.e. warm weather.
AREAS OF CONTROL
Because of the nuisance value of the flies and their egg laying ability, control is aimed at the adult fly, using adulticides. The use of chemicals must be done with caution due to the potentially toxic effects of many chemicals.
Aim to place these chemicals in areas where the flies are seen to be resting, such as sunny sheltered areas, brighter areas and protuberances from the ceilings etc.
Many adulticides or flytraps contain a substance in order to attract flies. It is therefore advisable to place these traps away from homesteads and places you are foremost wanting rid of flies.
Flies are attracted to protein sources, so will be attracted to feed bins, rotting material, manure etc. It is therefore essential that spilt feed be swept away, manure and chicken litter be managed in the correct manner, by making sure it is able to dry out and is kept in a designated area in order to control fly breeding, either with chemicals or by turning the manure or compost. Compost such as grass cuttings is an ideal place for fly breeding, so management of the compost heap is critical.
Mortality pits and disposal of broken eggs is another area of concern. These pits must be covered or burnt on a very regular basis.
The larvae are the next area of control. Larvae play an important role in assisting to break down decaying matter along with other organisms such as earthworms, beetles etc. It is not advisable to spray decomposing material with a poison that will kill all forms of life in the material, as this will prevent breakdown of this matter.
In-feed products are available in poultry feed. These products are excreted in the urine, which comes out with the faeces and remains in the chicken litter acting on the larvae by preventing them from progressing either into the next larval stage or the pupa stage. Maggots will be seen in the litter and will assist in the breaking down of the litter, but will not develop into pupa and flies.
It is important to make sure that chicken litter does not become wet and therefore leach the medication out of the litter, attention must be paid to leaking drinking nipples, waterlines etc.
Products are available to spray on the litter and compost heaps, which will act in a similar fashion to the in-feed medication in poultry.
As said previously it essential to manage chicken litter, compost and waste correctly in order to prevent fly breeding from occurring.
In calf pens with deep litter systems the calves will trample the manure and therefore prevent the life cycle being completed, but it is important to clean areas under the rails and gates and feed buckets where the manure is not being trampled. Manure that has fallen of trailers and left lying at the side of roads is a potential breeding site; this must be removed.
Drains are another problem area and should be cleaned out on a regular basis preventing organic material from building up. Grass and weeds growing into drains is an excellent area for fly breeding and must be removed physically or with chemical non-toxic to fish and birds such as Roundup.
Kikuyu and weeds growing at the edges of slurry pits are also problem areas and must be sprayed with Roundup.
In conclusion it can be noted that 90% of fly control is through good management and the remaining 10% would be with chemical control, making fly control not as expensive as one would imagine.
Date published: 2003-12-01