Sunday, March 21, 2010

Cluster Flies Clustering Early

Have you seen cluster flies congregating around your home or sheds already this season? Let me know by replying below.

They are named cluster flies because of their habit of congregating in large groups or swarms in dark places such as attics, corners of dark rooms, 'nooks and crannies' and 'cracks and crevices'. Each fly releases a pheromone (smell) that attracts others. This pheromone will linger on even after all the flies have been destroyed and removed and thus will continue to attract cluster flies to that area so that the clusters keep recurring. It is therefore important that treatments are continued even when there are no flies present.


These flies are an increasing pest in areas of grassland pasture or lawns. The larvae of the flies feed on earthworms and emerge as adults to mate. In autumn the adult flies congregate to survive through the winter and once warmer weather arrives in spring they emerge from their ‘hibernation’ to lay eggs on surrounding grassland, pasture and lawns. So there tend to be two times of the year that these flies bother us in homes and other buildings; autumn when they congregate and spring when they emerge from their hiding places.

While congregating and when 'waking up' after winter they are often found emerging from light fittings, window frames, other cracks and crevices. The flies are matt black, hairy, slow moving and the word most used to describe them is 'gross.'

How to get rid of Cluster Flies and keep them away
Kill the adults to prevent them laying eggs in surrounding grass. Kill the larvae in the grass to prevent the adults clustering in your buildings.


If possible it is best to prevent the problem of these flies moving into your home by treating the larvae in the soil before they become adult flies. Use Lawngard Prills which is a slow release insecticide for removing pest insects from the soil. This is an ideal product to protect you from Cluster flies. Sprinkle these prills on grassy areas within 100-200m of your home.

When cluster flies are seen around a building on the outside, this is usually in the late summer and autumn, this final adult stage before clustering inside can be controlled with NO Flies Bait placed in strategic places around the exterior.


If you have the adult flies swarming and clustering in the house or other building you need to carry out a program of treatment.


Check around your house/buildings for clusters of flies in warm, dark, dry corners specially your roof void and eaves. If these can be accessed, spray the clusters with NO Bugs Super. If the clusters cannot be found or accessed use NO Bugs Bug Bombs or NO Bugs Borafume fumigators in the voids.


Once the flies in the cluster are dead, clear away as many bodies as can be reached. If you use a vacuum cleaner ensure the bag is disposed of immediately. Spray the surfaces they were clustering on with more NO Bugs Super to prevent new clusters forming where the pheromone lingers.


Treat the surfaces around the home where flies have been seen and entry points to the roof void around the eaves etc. with NO Bugs Super.


Treat again prior to the next season to prevent new clusters collecting. Given a chance they will use the same areas to form clusters.

Why do flies follow garbage trucks? Because they like fast food.

36 comments:

  1. I have two large holly trees in my backyard at one end of our swimming pool. They are full of (what I guess)are cluster flies. I have never seen so many flies in one place. They are all around the swimming pool, the pool fence and the kids swing set. It is truly disgusting. Should I spray the trees?? Will that help get rid of them? Or should I cut down the trees? They are very tall trees. But, we cant even go outside at this point. Do holly trees attract flies?? Any help would be appreciated.

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  2. Hi Carey M.

    The flies you describe may be cluster flies. Are they dull black to grey and slow moving? If they are cluster flies spraying the trees and surrounding areas with NO Bugs Super (avoiding very delicate plants) will reduce the numbers. Check out roof voids and other dark dry spaces they may be forming clusters. If you find clusters forming in buildings carry out the treatment recommended above and on the Kiwicare website.

    Another possibility is that they are black flies attracted to honey dew produced by aphids or scale insects on the trees or surrounding plants. Have the trees or any other plants in the area got sooty mould? If so this suggests that sap sucking insects are attacking the plants and they are excreting honey dew which is attracting the flies. If this is the case spray the affected plants with a systemic insecticide and fungicide such as NO Insects Spectrum Powder which will control the sap sucking insects and the mould. You may subsequently spray with surface insecticide such as NO Bugs Super (avoiding very delicate plants) to deter the flies.

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  3. this blog!!! Its amazing!!!! A loved!!! Thank you very munch!!!!

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  4. Yup diagnosed this problem. Vacuuming 50 to 100 a day. And this is July in Michigan. I live in a rented modular home. Had a smell we just couldn't pin point. Think it is the cluster flies now. I hate this house.

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    Replies
    1. I could have written this comment. I hate my house too, and it has a funny smell....can't pinpoint, but after reading a bit about cluster flies, I think it's the flies I smell. We are having a warming trend (I also live in Michigan), right now....50s in November, so they are waking up and are in my house. I am close to staying in a hotel.

      Delete
  5. Hi Anonymous,

    Cluster flies are a problem, not just in New Zealand, but many temperate parts of the world.

    There are several different species of these flies. The smell you detect may be the attracting pheromone if you have a lot of flies, but this is not usually detectable from the cluster fly species common in New Zealand. What you may be detecting is the dead flies decomposing.

    You can't get Kiwicare products in the US (yet) but you should be able to find similar products and carry out the protocols as described above.

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  6. This comment has been removed by a blog administrator.

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  7. We live on a farm and have dogs and the flies are all over the grass in the dog yard. We keep it clean, picking up after the dogs right away. We vacuum up hundreds of flies in the house daily and we've noticed on the west side of the house in the afternoon, there are thousands of flies crawling on the house. How can we eradicate the flies but keep our dogs safe at the same time?

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    Replies
    1. Hi,

      Thank you for your comment. The program of control I have outlined above would be safe for your dogs. The only thing I would add would be to keep the dogs off the treated grass until the granular insecticide is well watered in.

      Delete
  8. Cluster flies have invaded the bedrooms on the north nd west side of the house in new Zealand several times this summer and last summer. They congregate around the wooden windows and squeeze their way in side. The only way i can control them is to keep all windows shut and spray around the window frames with fly spray so when they do enter they are dead. What time of year do I sprinkle the lawn prills and are they safe for a dog?

    ReplyDelete
    Replies
    1. Hi,

      Thank you for your comment. Ordinary fly spray will not be effective for long. Use a long lasting spray such as Kiwicare NO Bugs Super.

      Use the prills/granules on your lawn in late summer to early autumn so that the last cycle of larvae are killed before emerging as adult flies.

      Keep the dogs off the treated grass until the granular insecticide is well watered in. Then it is safe.

      Delete
  9. I am having trouble with swarms of these flies on the side of my house, I have a dog in which we clean the back yard of the fecies either daily or every other day, I have also cleaned out my trash can to try an eliminate the odor, but I still have the same problem, it seems like they just keep multiplying on a daily basis. What can I do to stop this?

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    Replies
    1. The flies may be cluster flies or they may be other species attracted by the dog feces.

      You could try applying a residual, long lasting, insecticide to the wall where the flies congregate.

      Delete
  10. We are having a problem with these (I think) this year, finding 50-100 a sunny day. They buzz around the centre of the rooms in groups & end up dead everywhere. I think they are in our upstairs roof. Its it toxic to Bug bomb the house, I have a baby and am reluctant to use toxins in the house.

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    Replies
    1. Hi,

      Thank you for your comment. There is no risk to you or your baby when using the Bug Bomb in your house to knock down the flies. But remember to remove all the dead flies as they will continue to attract more flies.

      Delete
  11. Hello,

    Thank you for your comment. Kiwicare Bug Bombs are safe to use as directed. As long as you leave the area when they are going off and for a few hours afterwards, leaving them to do their job, they are safe to use in all households. They kill the cluster flies there at the time and leave little or no residues. I suggest using them in the roof void where the majority of the flies are likely to be clustering.

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  12. I heard what sounded like a swarm of bees the other morning just before dawn. Then I heard it again the next morning and my husband went outside and called me. The neighbors tree next door had hundreds of thousands of what looked like flies swarming through and around the tree. We've lived here for 10 years and this has never happened. What does it mean and what can be done?

    Kelly

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    Replies
    1. Hello Kelly,

      Thanks for your comment.

      I am not sure exactly what has caused this fly swarm, but it could be they are attracted to tree due to honey dew from scale insects or another sap sucking insect. Look for insects or sooty mould on the tree. Kiwicare Super Spectrum would be a good option if you find an infestation.

      Delete
  13. Hello Kelly,

    Thank you for your comment.

    If you can answer some questions for me I may be able to advise.

    Where in the world are you?

    What sort of trees are they?

    Can you describe the flies? Size? Colour?

    Were they landing on the trees, or just flying around them?

    David

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  14. Yesterday we found some cluster flies, or stupid flies as I call them cause they're so slow and stupid, mainly in the kitchen windows of our apartment. We have only found a few stragglers in the living room or bedroom. I didn't know about cluster flies until I Googled it now, and I'm pretty sure this is what they are. We are on the third floor and we do not think any one else in our building is having this problem. We went outside and looked up at our kitchen windows and we could see 20-30 in each window, but we do not see any in anyone else's windows. We moved in last October and had a few flies here and there and it was annoying, but not even a fraction as bad as now! So I dont know if this happens every year here or not! We live in the south suburbs of Chicago and it has been very hot for the last few days, like upper 90s hot. I read how they hatch into earth worms and stuff, unlike regular house flies, and for the last two weeks I have had a container of worms in the fridge (left over from fishing that we haven't had the chance to use yet) but I haven't noticed any flies by the fridge and I'm too afraid to open the container of worms, worried a ton if larva will be in there or something. I just opened it the other day and fed them though and they were fine. I never notice a lot of flies outside, we have other normal animals and bugs in the yard like snakes, rabbits, mice and bees, but we leave all if them alone and they don't bother us. Now we have these damn flies. I was able to kill the clusters with some Ant/Roach killer spray, that the landlord happened to leave here on accident, and that just kind of stunned them and I knocked them to the floor and swept them up and flushed them down the toilet. Our windows open from the top and bottom and we have tried to shut them as much as we could, and lock them, but some of the top windows don't meet where the top of the bottom do, but there are not ant cracks where they could get in. We are very clean and do not leave any food out or garbage laying around. I would appreciate any insight you would have.

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    Replies
    1. Hello Anna,

      Thank you for your comment and question.

      You have dome much of what I would suggest. The flies have not chosen your house because of poor hygiene, they are just looking for dark, dry, sheltered places to survive winter.

      You should use a long lasting residual spray such as NO Bugs Super around possible entry points and ill fitting windows. The product can be painted or sponged on to window frames.

      Delete
  15. I have numerous/100s of flies at my kitchen dining windows. I vacuum and leave for work. Come home and more there. We have a vegetable garden and am constantly bringing in fresh tomatoes and peppers etc. How are they getting in my house? Are the tomatoes attracting them. I leave the back door open some for my dogs to come in and out--maybe 5 or so minutes at a time but they remain closed and locked while I am at work. Should I bomb the attic or the whole house.

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  16. Hello,

    I think the first thing to do would be find out what sort of fly they are. If you can send me a good photo I may be able to help. I would also need to know where in the world you are.

    Do you use natural organic matter on the your vegetable patch and do you have a compost heap? Do you or a neighbours keep chickens or other animals?If so these could be where flies are breeding.

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  17. We have just.done our.garden up and have cut our grass for.the 2nd time as this time it was.gettong.VERY.long.in places.... i have just been outside to put my washing out and found a cluster of flies around the grass area that was very long... they are black, shiny and horrible!!! What can i do?.please help.as im having to keep my littleones inside.. many thanks.kathy x

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  18. Hello Kathy,

    Thank you for your comment and questions.

    Can you tell me where in the world you are? It may help me identify the flies.

    However, it is unlikely that the flies are cluster flies and it is also unlikely that the flies would be harmful enough to require you to keep your little ones inside.

    My guess from your description would be that they are blow flies. Perhaps an animal (rat, mouse, bird etc) died amongst the long grass and the flies have just emerged from the carcass. If so they will leave soon.

    i hope this helps.

    David

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  19. Hi there, i have noticed that my vege garden has a patch of blow flies on it daily in clusters... we watched some come from under the dirt... you mentioned above that they cant b cluster flies but they are in clusters and keep comng into the house... if u disturb them they all go right back into a cluster in same spot... does this mean my veges are now non usable?? And if i put those pills in that u mentioned will it harm the veges or cats? This is my first year using my own compost i made so could that be what has brought them to my garden this year? I live in bay of plenty nz... how can i get rid of them and do i need to re start my whole vege patch again?

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  20. Hello Tracy,

    Thank you for your questions.

    I suspect the flies you have seen are another member of the blow fly family and are breeding in the compost you mentioned. They are unlikely to harm the veges and so long as you wash your vegetables they will be safe to eat.

    The Lawngard Prills whaich can be used to control many sorts of soil insect pest are safe to use between rows of veg, but should not be applied on the veg themselves. They should be well watered in after application.

    I do not think it would be necessary to re-start your vege patch. I hope you will continue to harvest good healthy veg from it.

    David

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  21. Hello David, got a severe fly problem in a recently purchased property. Believe them to be cluster flies but I obviously lack any real knowledge. Black/dark brown in colour small but fat flies, noticed initially on the Northern side of my house around the windows on the inside, both dead and alive in groups of 50-100. Treated with a supermarket aerosol and hoovered up immediately but always returned the next day again dead on the floor and alive around the windows. This was late October all the way to early December time. Have now realised there are possibly thousands in my attic and I have searched thoroughly up there for any dead vermin or even people only to find nothing! My girlfriend is horrified by them and I feel really guilty killing them but it's us or them hahaha

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  22. Hello,

    It does sound like cluster flies. Supermarket aerosols will kill the flies your spray but has little or no ongoing protective action. If you get them returning use a residual surface spray (either ready to use trigger or concentrate made up with water) and treat all the eaves, window frames and other access points or dark shady cracks and crevices or other dry, places around your home.

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  23. Hello David,

    I'm in the UK and recently found hundreds and hundreds of them hibernating in my loft. I've read that the problem may ease in the summer so I have just finished the first treatment and will do another i a few months when it gets warmer.

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  24. hi david i am in the uk and have just moved into a new build house, i have noticed every day there as been a fly in my bathroom i have looked outside at the building and at the back of the house there was about 10 flies on the wall leading to my bathroom i asked my neighbour if she has any and she said no. do you think these could be cluster flies they are bigger than a house fly and a lot slower in movement can you advise me please,

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    Replies
    1. Hi,

      In the UK it is late winter and I would not expect cluster flies to be clustering at this time of year. But they could be cluster flies waking up if you have had warm weather. Take a close look at the flies. If they have shiny bodies they are probably blow flies of some other types. If they are dull they could be cluster flies and I suggest taking a close look for clusters in your roof void.

      Delete
  25. Hi, I am in the lower south island of NZ and exactly a year a ago i had my house sprayed for cluster flies. Now they are back and seem as a bad if not worse than last year. Is there any easy way to get rid of them that is cheaper than spraying / gases or is this my best option. And how can i stop them returning next year!

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    Replies
    1. Hello,

      Thank you for your enquiry.

      At this time of year (autumn) your best option is to spray with a residual insecticide such as No Bugs Super. Treat the exterior surfaces of your home/buildings paying particular attention to possible entry points at eaves, dark dry crevices such as gaps around window frames, and treat interior spaces such as roof voids where possible.

      It might be too late but it could be of benefit to apply soil insecticide such as Kiwicare Lawngard Prills to lawns and grass areas close to the buildings. This will control any flies still emerging from the soil.

      If clusters begin in voids, spray them or use Bug Bombs and clear up any dead flies accessible.

      Be pro-active and prevent clusters growing. The larger the cluster gets the more pheromone released and the more flies are attracted.

      Kind Regards

      David

      Delete
  26. Hi,

    I wanted to ask you, as to what do i do to get rid what sounds like a cluster of flies in my loft? I started hearing a buzzing sound in my room and at first i thought it was something to do with the electric but it has got louder and now i believe they are flies that seem to have got through to the loft.

    i'm not sure what to do since its dangerous to go out in the loft because the ceiling/floor isn't strong enough to hold anyone.

    Please help!!

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  27. Hello,

    In your case, check with a torch to see if you can see cluster fly clusters or ant signs of wasp or bees.

    If you can't get into the loft safely i suggest you use fumigators. Check to make sure you use sufficient for the volume of the loft and factor in the likelihood that the loft will be well ventilated.

    Kind Regards

    David

    ReplyDelete

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