# Question: Why - do not feed when applying Formic Pro?



## Jack Grimshaw (Feb 10, 2001)

Someone from a FB group called Nod to ask that question.The answer was that during product testing they saw increased bee mortality when feeding with in hive feeders,especially in the first 3 days.
Open feeding is OK.


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## bobo (Feb 15, 2015)

Thanks Jack,

Any ideas what may be the cause of the mortality?


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## Jack Grimshaw (Feb 10, 2001)

I imagine that the syrup somehow absorbed formic acid from the vaporization of the strips and was toxic when ingested or some how burned the mouthparts or digestive system of the bee.


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## sjj (Jan 2, 2007)

bobo said:


> Thanks Jack,
> 
> Any ideas what may be the cause of the mortality?


The robbing bees were killed.


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## Oldtimer (Jul 4, 2010)

Yes that's the other aspect, robbing.

Formic acid is a disruptive treatment and can reduce a hive's ability to defend itself, making it more prone to being robbed. Feeding syrup at that time is just compounding the risk factors.

A person may get away with it, but then again, may not. My view, feed before or after, but not during. If after, I'd leave a few days or a week for the hive to re organise, before feeding.

If the issue is timing, ie, winter is coming I only have so much time to feed plus do treatment, there is really no need to take weeks to give a hive it's winter feed. You can slam dunk 4 gallons of syrup into a hive in just a few days if the hive is healthy and a large capacity top feeder is used and set up properly. So, do that, then treat, then feed some more if needed. If the hive is noticeably suffering with mites, a less harsh treatment type could be a better choice, and most of them, feeding can be done during, with no issues.


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## HarryVanderpool (Apr 11, 2005)

It runs counter to the research done back in the day when we used liquid formic.


https://www.researchgate.net/publication/237698512_Results_of_50_formic_acid_fumigation_of_honey_bee_hives_Apis_mellifera_ligustica_Hymenoptera_Apidae_to_control_varroa_mites_Acari_Varroidae_in_brood_combs_in_Florida_USA


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## bensbienen (Jul 31, 2020)

I've been told that the sugar syrup might absorb some of the formic acid from the air, therefore lowering the acid concentration in the air and treatment will be ineffective.


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