Fly control is an essential part of pig farmers’ operations. Excessive fly pressure increases stress and is unpleasant for both animals and humans. Flies can also spread diseases. Pig farmers have various options for controlling fly pressure.
Depending on climate and location, fly pressure can increase rapidly. Pig farmers have several options to minimise fly infestation, but, in general, these options are costly and laborious. Various suppliers recommend a range of products. Insect growth regulators are a commonly used method to reduce fly infestations.
While chemical agents were previously widely used to suppress infestations of flies, mice and rats, there has been a clear trend towards biological control in recent years. This development is partly due to increasingly strict laws and regulations regarding pest control. In roughly 30 years, fly control has undergone significant changes: from treating symptoms to preventive measures, and from chemical treatments to a fully organic approach. Pest control companies operate under the IPM (Integrated Pest Management) method, which focuses primarily on preventing the arrival of nuisance pests rather than on pest control.
Disease vector
Pig farmers are very keen to keep fly pressure on their farms under control. Flies are proven disease vectors and can cause stress in pigs. Too many flies create a nuisance for both the animals and their caretakers. Pig veterinarians emphasise the importance of fly control. “Fly control is very important. It’s part of good basic management. Too many flies in the barn makes the animals’ living environment uncomfortable. It has also been shown that flies can spread streptococci and PRRS,” says Dutch pig veterinarian Marrina Schuttert.
Her colleague Robin van Kampen agrees. Fly control is part of stockmanship. It’s simply something you must have on your radar. Low fly pressure is part of overall farm hygiene and benefits the pigs’ welfare. The animals can lie down peacefully without being bothered by those annoying insects. As flies are proven vectors of bacteria and viruses, among other things, keeping fly pressure low is also advisable from a health perspective. Flies are not wanted, although achieving a completely fly-free barn is challenging.
“Flies cause discomfort”
Schuttert knows from the field that fly pressure varies from farm to farm. The differences can sometimes be significant. “After winter, when temperatures rise, you see small fly outbreaks here and there. Flies cause discomfort and irritation for the pigs. Moreover, fly droppings on lamps, for example, are dirty and negatively impact light output.” On a positive note: ‘’Most pig farmers have fly pressure under control. At the same time, I see pig farmers sometimes shrug their shoulders at a few flies in the barn.”
Manure pits as habitat
Flies thrive in manure pits, which are moist and nutrient-rich. The insects lay their eggs in places where wet becomes dry, for example, on manure crusts. According to Schuttert, manure pit ‘management’ can be used to limit fly development. “Ideally, the pits are completely emptied in a short time. That breaks the fly cycle. If the manure is more difficult to dispose of due to weather or regulations, the fly habitat is maintained.”
Pig farmers can choose from various methods and resources to manage fly pressure on their farms. Schuttert sees the use of predatory flies on the rise. “I think biological fly control using predatory flies is a good method. It’s good for both animal and human welfare. When using chemical agents such as insect growth regulators, you do wonder about the impact on the composition of the manure and what is ultimately spread.”
From chemicals to organic pest control
Joan Rooijakkers, director of Dutch company Agro Pest Control (APC), has dedicated himself to pest and fly control for the past 3 decades. He sees a clear shift from the use of chemicals to a fully organic approach. “When I started, I wore a protective mask in the barn for days on end. Chemicals were becoming increasingly expensive. Farmers were spraying themselves to death. That caused frustration, including for me. ‘Is this it, being covered in poison all day?’ I asked myself. As a pest and fly controller, I didn’t exactly consider this my dream job. I wanted to change that.”
Rooijakkers’ starting point is the pest and fly-free barn. According to him, this is possible with a fully organic approach, without the use of chemicals. “Once you’ve started with organic pest control, you don’t want to go back. But it was a journey to get there.”
Labour savings
Biological control requires time and attention, says Rooijakkers. “We don’t just sell our product to everyone, but visit every barn. The infestation rate varies. That is our starting point.” Depending on the starting point, an action plan is developed for biological fly control. The approach is essentially aimed at preventing adult flies from being present among the animals (see box).
Rooijakkers states that biological fly control is always cheaper than using chemicals. “Using insect growth regulators is labour-intensive. The costs of chemicals and labour have increased significantly in recent years. With biological control, the ultimate labour requirement is zero.” When using chemical agents, Rooijakkers warns of the risk of resistance and the presence of biocides in the manure, which is an additional negative factor to keep in mind.
