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Cluster Flies on the Rise? Exploring the Surge of Cluster Flies in the UK

Updated: May 16

Cluster Flies on the Rise? Exploring the Surge of Cluster Flies in the UK

As the cluster fly season advances across Hereford and the Wye Valley, at PGM & Son Positive Pest Control Hereford, we offer advice and solutions for your cluster fly problems.

PGM & SON Pest Control Services; Cluster Flies on the Rise? Exploring the Surge of Cluster Flies in the UK

These insects are called cluster flies because of the way they form clusters when they hibernate.

Frequently, they cluster in very large numbers.

Although they don't bite they are a nuisance because of the volumes in which they congregate in properties to hibernate over the winter period.

Often found in upper rooms in houses and loft spaces, the cluster fly is mainly found in rural areas due to their life cycle.

In the Summer they live and feed in the fields so do not normally cause a problem. They are parasitic on earthworms and their larvae live in the soil. Emerging as adults at the end of the Summer period, they hibernate in dry sheltered areas.

You will often come across them congregating in large numbers on the outside of buildings especially on south-facing sunny walls. When the temperatures start to drop they tend to crawl into crevices for shelter sometimes through window frames but also often under the eaves or fascia boards into the roof space.

Increased Sightings of Cluster Flies in the UK

Over the last few years PGM & SON has been a noticeable surge in sightings and reports of cluster flies across various regions of Herefordshire and Worcestershire. This uptick in cluster fly activity has caught the attention of homeowners, businesses, and pest control professionals, signaling a potential shift in the dynamics of fly populations in these affected areas.

One of the most prominent indicators of this increase is the sheer frequency of sightings reported by individuals and organisations tasked with monitoring insect populations. From rural landscapes to urban environments, reports of clusters of flies congregating in homes, businesses, and outdoor spaces have become increasingly common.

PGM & SON; Cluster Flies on the Rise? Exploring the Surge of Cluster Flies in the UK

This rise in cluster fly sightings is particularly evident during the transitional seasons of spring and autumn, when these insects tend to become more active and seek shelter in buildings to hibernate or overwinter.

However, what sets this recent surge apart is the scale and persistence of the phenomenon, suggesting underlying factors driving the proliferation of cluster flies beyond typical seasonal fluctuations.

Several factors may be contributing to the heightened prevalence of cluster flies in affected areas.

Climate change and cluster flies

Changes in weather patterns, including fluctuations in temperature and precipitation, could be creating more favorable conditions for fly breeding and survival. Additionally, alterations in land use, such as the expansion of agricultural practices or urban development, may be disrupting natural ecosystems and providing cluster flies with new sources of food, shelter, and breeding sites.

Furthermore, human activities, such as the widespread use of pesticides or the accumulation of organic matter in and around residential and commercial properties, could be inadvertently promoting the proliferation of cluster fly populations. These factors, combined with the inherent adaptability and resilience of cluster flies, may be fueling their resurgence and contributing to the observed increase in sightings.

The implications of this rise in cluster fly populations extend beyond mere nuisance, posing potential challenges for homeowners, businesses, and communities. Increased infestations can lead to heightened levels of annoyance, discomfort, and even health concerns for individuals exposed to large clusters of flies.

Moreover, the economic impacts of cluster fly infestations, including damage to property and the costs associated with pest control measures, can impose significant burdens on affected individuals and businesses.

As reports of cluster fly sightings throughout the UK continue to mount, it becomes increasingly important for pest controllers to monitor and address this issue proactively. By understanding the factors driving the increase in cluster fly populations and implementing targeted control and prevention measures, communities can mitigate the impacts of these pests and preserve the health, comfort, and well-being of residents and businesses alike.

If you don't want to share your property with swarms of flies or your business is putting off customers with a cluster fly problem, call PGM & Son on 01981 540088 or email us at

Want help getting rid of your cluster flies? Looking for cluster flies pest control?

PGM & Son Hereford can offer advice and solutions - call today for a no-obligation chat.

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2 comentários

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05 de jun.
Avaliado com 5 de 5 estrelas.

It is worth considering that, over the past 30 years or so, stubble burning has stopped on farms along with a reduction in the use of harmful chemicals and the use of more organics, all of which has increased the worm populations on farmland. As worms are a host for the cluster fly it seems reasonable that we would eventually see an increase in their population as well.


02 de abr.
Avaliado com 5 de 5 estrelas.

Very helpful, thanks.

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