Fly Blocks-Do They Work : LUSENET : Countryside : One Thread

Does anyone use fly blocks? The sort that cattle lick. Do they work? Also, how do they work? I assume they have some sort of chemical in them, if they do, are they safe for a beef steer or a milker, it seems they wouldn't be with a chemical in. Would like views from people who have used them.

Thanks for any input you can give,

-- Carol K (, April 16, 2002


I used them one year and thought they were great - until I saw that my cow patties never did break down. They just hardened and dried and stayed around. Anything that attacked the manure was killed by the larvicide. I quit using them because I wanted the manure broken down as soon as possible. I began using chickens, ducks, and guineas to control my fly problem. They helped to spread the patties as they dug for worms and larvea.

I am pretty sure they are labeled as to what our government thinks is safe for consumption. In my opinion, if worms can't eat it, there must be something wrong.

-- dave (, April 16, 2002.

There are different formulations, be SURE to read the label!!!! Especially with dairy cows, must be very careful because everything gets concentrated in the milk fluids. Beef it's often a 5 day to 3 week withdrawl period - again depending on what exactly you are using.

They work, but you must hit the right timing for real control. If you miss the window of oppertunity, they will not seem very effective.

The rest depends on how you feel about fly control vs your safety level with pesticides, and if you trust govt scientists & testing or not. You won't get a 'right' answer on this, only deeply divided opinions. :)


-- paul (, April 16, 2002.


Fly blocks work, but only on the manure patties from the treated animals.

If you have neighbors with cattle who do not use the fly blocks the flies will still reproduce on your neighbors' places and come to visit your cattle. In short, unless you control vast expanses of pasture and treat all your cattle, the fly blocks are more or less worthless.

The best thing I have found for flies is the permectrin pour-ons that last about two to three weeks. Any fly that lights upon a treated animal is a goner within minutes. What is more, I have discovered that I need not treat more than a half or third of my cattle. Since the flies do not stay on one cow, treating a part of the herd kills all the flies. Treat today, and tomorrow no flies on any cow. Generally I treat about three, no more than 4, times a year.

I do not re-treat until I see flies getting heavy after the previous treatment. As the summer wears on the flies are thinned out so that they do not reproduce so rapidly and treatment is less important. Of course I am killing my neighbors' flies too, but that is immaterial so long as my cattle are comfortable.

If you have a small herd of pets you can just walk among them and use the little dipper to pour down the back line. If the cattle are a little less accomodating, run them thru the chute to pour on the Permectrin, but try treating only half and see if you are not pleased with the results.


-- Jimmy S (, April 16, 2002.

It isn't rocket science. Fly blocks contain sulfer in levels that flies don't like.

-- Dennis Enyart (, April 18, 2002.

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