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Farnam Companies, Inc. — Item #12587
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Breaks the fly life cycle

  • Prevents the formation of fly larvae's exoskeletons when they molt (resulting in their death)
  • Contains no organophosphates & can be used as part of an integrated pest management program
SimpliFly with LarvaStop is a highly palatable additive to prevent the development of stable flies and house flies in the manure of treated horses. LarvaStop breaks the fly life cycle by preventing the formation of fly larvae's exoskeletons when they molt (resulting in their death).

SimpliFly contains no organophosphates and can be used as part of an integrated pest management program. SimpliFly with LarvaStop is a reduced-risk pesticide.

View our Insect Control Supplement Comparison Chart


Active Ingredients:
  • Diflubenzuron (Dimilin)
Inactive Ingredients:: Wheat Middlings, Dehydrated Alfalfa Meal; Calcium Carbonate; Sodium Chloride; Calcium Propionate (preservative)


Instructions for Use:
Feed the recommended dosage of SimpliFly to each horse separately to make certain he receives his full portion. This product should be fed top dressed on grain or mixed with the horse's total ration to provide 6.8mg of diflubenzuron per 100lbs of body weight. For an occasional finicky eater who does not accept new feeds readily, mix this product with sweet feed or grain ration.

Daily Dosage
300 - 500lbs : feed 2/5 oz. per horse per day
500 - 700lbs : feed 3/5 oz per horse per day
700 - 900lbs : feed 4/5 oz per horse per day
900 - 1100lbs : feed 1 oz per horse per day
1100 - 1300lb horse : feed 1 1/5oz per horse per day.
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    out of 5
    91% of customers would recommend this product to a friend!
    Tell us what you think!

    The reviews provided on this website represent the experience of the individual posting the review. We do not adopt, edit, or endorse any of the submissions posted within the reviews section. Rather, the reviews are part of an online community of animal owners that desire to share their particular experience with other individuals. These reviews are not a substitute for discussing the health of your animal with a veterinarian.

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    SimpliFly is rated 4.5 out of 5 by 174.
    Rated 5 out of 5 by from No more flys It's amazing... A month on it, and I see the difference. Just keep your schedule right to auto-Ship. That way flies stay away. Away from Manure!
    Date published: 2014-08-16
    Rated 5 out of 5 by from This works! I have used the predators for two years, before that I had used Simplifly for 3 years. The flies are the worst I have seen in two decades, predators just couldn't keep up and I was doubling the numbers. Went back to Simplifly in late July. With 40 horses at the stable, tons of traps that were filling in a few days and using fly spray for the first time in many years we are finally seeing a drop in the numbers. The flies that are affected by a lavacide (or predators) are dropping in numbers. The traps are filling at a slower rate and this is the prime time in my area for flies. I will stay with Simplifly until the fly season is over. It's a great product. Every horse on the place waits for their 'treat' of Simplifly.
    Date published: 2014-08-16
    Rated 5 out of 5 by from No swishing tails!!! I bought this product at the beginning of June. And ever since I started all 4 of my nags on it I have had zero fly problems!! I still fly spray them about every 3 days but that is because one of them has flea allergy dermatitis. The price if the largest bucket is a little pricy but if it helps that much I don't mind getting it for all my babies.
    Date published: 2014-07-14
    Rated 5 out of 5 by from ZERO flies (Believe it !!!) One horse; 5.5 acres, all pasture; sandy soil; 9 mos of fly-breeding season per year.Length of use: 2.5 yrs. Number of flies NOW seen per day: 0 to <1. Number of flies seen per day 1 yr ago: 5-10. Number of flies seen per day 2 YRS AGO: 100-200 !!I've even been able to switch back to sweet feed without the risk of breeding flies.<><> For horses in Florida: Do not stop feeding during the winter, because we'll have periods when soiled material could breed flies.<><> Be sure to practice good manure management. I spread manure (3" deep) in rows over my pasture, then mow over it every week or so. When I owned several horses, I burned my manure between layers of hay, and it would smolder for several days, leaving only ash which I'd recycle into the pasture. Do not light your piles on fire in low-humidity States, because a brisk wind could upend a chunk of hay and set the woods on fire.<><> NOW I WANT A PRODUCT THAT DESTROYS BREEDING GNATS. How about it, Farnam?!!?
    Date published: 2014-07-07
    Rated 5 out of 5 by from SimpliFly Works! I have used SimpliFly for over 2 years now and am very pleased that SmartPak chose to carry this product. I have had super results and cut down the fly population in the pastures by 75%.
    Date published: 2014-07-05
    Rated 5 out of 5 by from IT WORKS! I used this product by Farnam decades ago, under a different name..... SO glad I tried this..... was wondering why they stopped making Equitrol, since it was so effective..... It's BACK, and better than ever. Wish all horse owners would use it for the benefit of no flies breeding in manure!!!
    Date published: 2014-07-04
    Rated 5 out of 5 by from Amazing! Almost none of the flies as last year! After dealing with flies all last summer, I figured this stuff was worth a shot (although it did seem too good to be true). I started all 4 of my horses on this prior to the flies arrived (in early March) and cannot believe what a difference it has made in our pasture! There are no nasty fly babies swarming around the manure and have not even had to break out the fly masks this year! Pretty great considering last year we had them on practically nonstop. HIGHLY recommend.
    Date published: 2014-06-18
    Rated 5 out of 5 by from I Can't Believe It! I already wrote a review for SimpliFly, but I only had been using it for a month. I'm now 2 months into using it, and we have NO flies! Seriously, none. We have gnats and still have the giant, nasty flies, but I expected that. It's not that the flies aren't out - they are, I've seen them at other well-maintained horse properties - but SimpliFly has annihilated our fly population at home. I was going to order fly masks, as our only remaining one is torn, but honestly, I don't need to. I didn't believe that the results would be this incredible, but they truly are. I'll reiterate from my last review: we have three horses on a small 12 acre property, only about half of which is usable (the other half is house/yard/super-steep mountainside), with a limited area for manure management. I live in southwest Colorado, and we've had more moisture this year so far than last, but it is fairly dry. I hope this review helps anyone on the fence about trying this product. It is also highly palatable; my picky mare eats it without a complaint.
    Date published: 2014-06-12
    Rated 5 out of 5 by from Great Product Second year using - great results. Eliminated the fly problem.
    Date published: 2014-06-11
    Rated 5 out of 5 by from Seems to be working! I have only had my horses on this for one month, but we've had warmer temperatures and I have not seen a single black fly at this point, when, normally, there would be a few starting to come out. Since it has only been a month, and it's still early in the season, I can't say for certain that it is working well, but I definitely would expect to see more flies this time of year, with the weather we've had. I have 3 horses that spend most days in a dirt turnout, with some pasture time (limited grass right now), and I expect the fly season to be horrendous, so I decided to try Simplifly with Larvae Stop. I'm hoping that I continue to see minimal flies. So far so good!
    Date published: 2014-05-27
    Rated 5 out of 5 by from The way to go! I have been using Simplifly for three years now and it is the major part of my fly control at the barn. My boarder says I have fewer flies in the barn than she has in her garage. Its a great product.
    Date published: 2014-05-25
    Rated 4 out of 5 by from Does What It Says I've been using SimpliFly since late April, I should have started sooner but that was my fault. I have been using it for a solid month now, and am very pleased. Sure you still have the flies, if you have a horse you have flies. But this product sure cuts that population down to a minimum. I am glad that SimpliFly was suggested to me and will always keep this product on my barn shelf.
    Date published: 2014-05-21
    Rated 4 out of 5 by from Easy to use! I bought this about a month and a half ago. It seems to be working pretty good, not as many flies as usual.
    Date published: 2014-05-15
    Rated 5 out of 5 by from very palletable My horses are all on simplfly and so far the fly population is down and the horses do not mind the tast at all!!!
    Date published: 2014-05-14
    Rated 4 out of 5 by from Helpful Have used this product several years running. While this will not rid your property of flies, it puts a huge dent in the fly load-consistently. As I type this I see 4 flies on the windowsill. I am slightly alarmed as I would not usually see this until we are well into the hot summer months. This product has not let me down in the past, so I guess its a wait and see this year. Perhaps these flies belong to my neighbor and are Simplifly visiting.
    Date published: 2014-05-13
    Rated 5 out of 5 by from Works well
    Date published: 2014-05-13
    Rated 5 out of 5 by from Fewer and Fewer Pesky Flies! I have used SimpliFly for 3 years now and I see the definite difference in the number of flies in the pastures and around the barn. This also means content horses able to relax and not swat flies constantly. I use this along with a supplement to repel flies and we are all happier.
    Date published: 2014-05-12
    Rated 5 out of 5 by from This stuff WORKS! I've been using this stuff for 3 years now and it works well! Best thing I've used! No, it doesn't repel flies. What it does is inhibit flies from laying eggs in manure. I live in southeast Alabama where bugs are terrible. I saw a dramatic reduction in black flies, stable flies, and horse flies. Totally worth it! And it works best when you keep your horses on it year round. IMHO.
    Date published: 2014-02-24
    Rated 1 out of 5 by from No noticeable difference Used product per the instructions religiously for 5 months with no noticeable difference in fly population. The cost of the product not worth it. I do clean paddocks daily and hang fly traps.
    Date published: 2013-09-07
    Rated 5 out of 5 by from No More Flies! I have been using Simplifly now for about 4 years and our fly population has gone down to nearly none. This the best investment and so simple to use. No sprays or larvae, just add to your regular feed and you're done! I highly recommend this product.
    Date published: 2013-09-03
    Rated 5 out of 5 by from I'd never be without Simplifly In Norco, flies are the unofficial bird! We can never get rid of them all because of the people who dont use Simpifly but I do notice a BIG difference around my barn. We have 5 horses and it really works! I even notice a difference in my manure cans - no bugs
    Date published: 2013-08-25
    Rated 5 out of 5 by from Really Works! This product really helps cut dow the fly population on the farm.
    Date published: 2013-07-15
    Rated 5 out of 5 by from
    Date published: 2013-07-11
    Rated 3 out of 5 by from Ehhh My horses ate it all up without any problems. However, it didn't work at all. My pony still go fly dermatitis and had flies all over her. I didn't notice any less flies in the barn/turn out. And now my 8 year old horse has a tumor on her thyroid that popped up about a month ago and she had been on these for 2 months, so she is now off it, as is the pony.... would not recommend.
    Date published: 2013-06-21
    Rated 4 out of 5 by from Actually Works! I was very skeptical at first with this product but the flies here in N. FL are BRUTAL so I was willing to spend the money and give it a shot. It took about a month to really see a difference...but the flies and knats that were always bothering her are now barley a nuisance. She doesn't even have to wear her fly mask anymore. I also use Freedom 45 topical for the mosquitos, fleas, and tics and that works great as well. So, if you decide to use it, make sure that you give it a full month to see a difference. My "Whiskey" is one Happy Mare Now! :)
    Date published: 2013-06-12
    Rated 5 out of 5 by from Must have for this time of year! I always hated to run out of this for even a day because I would notice a big difference in the amount of (increase in) flies, and it would take some time for them to fall (decrease) off.With this added to my smartpaks I never have to worry about this again! Thanks!
    Date published: 2013-05-11
    Rated 4 out of 5 by from
    Date published: 2013-05-07
    Rated 1 out of 5 by from Didn't work for us :-( All of the horses were given this product. No other horses nearby but after 2 or 3 months of using the fly population is just as bad. We are having to resort to a fly spray system in the barn instead. Seems like a great concept and perhaps worth a try but just didn't work for us.
    Date published: 2013-01-12
    Rated 5 out of 5 by from seems to do the job We have had problems with only one type of fly all summer. This is a very small black fly that bites under the horses' bellies and clusters in the middle of their backs. We have not had any noticeable other files present in the barn or pasture areas.
    Date published: 2012-10-01
    Rated 5 out of 5 by from Great supplement Fantastic supplement. I put my gelding on this as the barn I'm moving to him uses it for their horses. The difference in the amount of flies/gnats around the manure is amazing. He can be a bit picky and eats it right up. Highly recomend it!
    Date published: 2012-09-04
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