Fly control made easier by a whole farm approach

As pests go, flies are the most visible aspect of poultry farming encountered by the general public.

Poultry units sited close to residential houses will always be under the threat of prosecution if flies become a nuisance. Flies also affect productivity and carry a plethora of diseases and parasites, like avian influenza, salmonella and worm eggs.

But eradicating flies is a difficult task. Each strain has a different life cycle, and requires a comprehensive and holistic approach to deal with them effectively. Two of the biggest mistakes that producers tend to make are not to act early enough, and to only treat the flies that they can see, says Lydia Parkin, pig and poultry manager at Novartis Animal Health.

“In poultry sheds, flies are able to reproduce all year round. I’ve had so many calls recently where fly populations are out of control; farmers really need to plan more in advance and apply an integrated fly control programme early in the year.”

Only 15% of flies are adult at any one time, with the remaining 85% in egg, larval or pupal stages, she says. “The most common flies in poultry units are houseflies and lesser houseflies, which have roughly an eight to 10-day lifecycle in the summer. Flies can lay hundreds of eggs in their lifetime, so if you are seeing adults, you are about to get a whole lot more.”

Unfortunately, chemical products designed to kill flies only act on one stage of their life cycle, and it is essential to tackle every stage if you are to succeed in reducing the population, says Ms Parkin. It is also important to monitor and record fly and larvae populations, to ensure prompt and targeted treatment, and adhere to strict biosecurity guidelines to limit disease transmission and fly breeding sites.

The first step is to paint a 1sq m white or yellow square on the wall and record the number of flies on it, twice a week in the summer and once a week in the winter, she says. Producers should also monitor maggots in the top 4in of the litter, particularly on slatted floor systems where the birds cannot feed on the larvae. “Flies like moist areas, so keep litter dry by avoiding spillages, collecting broken eggs and dead birds, and ensuring good ventilation.”

When using chemical treatments, farmers should select a larvicide to tackle larvae in the litter – ideally one like Neporex which does not harm beneficial insects like litter beetles, which prey on fly larvae. An adulticide can then be sprayed or painted on walls, beams and window sills to kill adult flies. “However, it is essential that you get dose rates right and rotate the active ingredient regularly to reduce the chance of resistance building up. This is a particular problem with pyrethroid adulticides, which should only be used infrequently.”

Beetles, mites, wasps and birds provide natural fly control, so it may also be worth buying in parasitic wasps. “Be sure to take a whole farm approach – monitor the fly and maggot population, find the source of the problem, and act before it gets out of control.”

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