Formic acid

[Finman]

Dr. R. W. Currie

Department of Entomology

University of Manitoba

Winnipeg,

Date Approved:
March 26, 2001

Project Status:
Completed September, 2003





Results and Discussion:

Dose-Time Exposure Relationship

Our results showed that the efficacy of formic acid is a function of the combination of dose and exposure time to which an individual hive is exposed. This combination of dose and exposure time is referred to as the concentration x time product (CT product). When the correct CT product was reached efficacy was greater than 95%. However, there was considerable variability in the actual dose each hive received even though the formic acid was evenly distributed throughout the air in the fumigation rooms. Concentrations of formic acid with the hive air are considerably lower than in the room in which they are housed. Hive air equilibrated with room air after a period of time that took anywhere from several days to several weeks depending upon the acid dose and hive characteristics. Colonies adsorbed formic acid and degassed the acid that had been adsorbed for several days after fumigation had ceased.

Both high and low dose treatments formic provided effective control of varroa mites in wintering facilities. However, when low-doses were utilized long exposure times were necessary to achieve acceptable levels of control. The advantage of low-dose treatments was that no queen loss was observed at exposure periods up to 47 days. Our high dose treatments did not cause excessive worker bee mortality when applied for periods of up to 9 days but excessive queen loss was observed when ventilation was not regulated. The best treatment strategy to maximize varroa mite mortality and minimize queen loss in our experiments was the low-dose long*exposure treatment.

 

[Finman]

Journal of Apicultural Research Vol. 43 (3) pp. 158 - 161
DOI --
Date December 2004

Article Title A study of the efficacy of formic acid in controlling Varroa destructor and its correlation with temperature in Iran

Author(s) R Bahreini, Gh Tahmasebi, J Nowzari and M Talebi

Abstract European honey bee (Apis mellifera) colonies infested with varroa (Varroa destructor) were used to compare the effect of treatment with tau-fluvalinate (Apistan) and formic acid (65%) during a 3-year period from 1998 to 2000. Twenty colonies were divided into 5 treatment groups, each with 4 replications. The groups were treated with either tau-fluvalinate (AP) or four applications of 20 ml (for a total of 80 ml (FA80)), 30 ml (FA120), 40 ml (FA160) or 50 ml (FA200) of 65% formic acid per colony applied over 16 days.

The percentage mite mortality due to experimental treatment was determined using the sticky board method.

Total mite mortality in the treatment groups over the 3-year period was 93.25% in the AP group, 60% in FA80, 75% in FA120, 59.5% in FA160 and 69.55% in FA200.

Treatment with formic acid was as effective as Apistan only in the third year when comparatively high ambient temperatures were recorded during sampling periods;

in year 3 the average temperature was 19.44 °C and mite mortality was 83% (AP), 89.25% (FA80), 95.25% (FA120), 75.67% (FA160) and 92% (FA200). In years one and two, mite mortality was higher in the Apistan group than in all formic acid groups, but none of the formic acid groups differed from one another.

The there was a significant (r = 0.0181) correlation between formic acid mite mortality and temperature, but no such relationship (r = - 0.05) between mite mortality and relative humidity.

 

[Finman]

DENMARK Questionnaire 2005 (Methods and results)


Organic varroa-treatment in semi- and professional beekeeping


Formic acid is used by all beekeepers, but in different ways. The use of the krämer board is the most predominant method. Used by 60,0% of the beekeepers. The use of free formic acid is also common used. Several beekeepers remarks that the free formic acid is used only in nearby apiaries. The nassenheider evaporator is used by 15,0%.

 

[Finman]

.http://www.medwelljournals.com/fulltext/?doi=javaa.2011.1106.1111

Journal of Animal and Veterinary Advances
Year: 2011 | Volume: 10 | Issue: 9 | Page No.: 1106-1111
DOI: 10.3923/javaa.2011.1106.1111

Efficacy Levels of Organic Acids are Used for Controlling Varroa (Varroa jacobsoni Qudemans) and Their Effects on Colony Development of Honey Bees (Apis mellifera L.)


RESULTS

Average Varroa infestation level (%) (mean±SE) and organic acid efficiency (%) before and after the experiment in spring

varroa infestation level before threatment was 13%.

reduction with oxalic acid 83%
with formic acid ...........82%


alive mites out of 1000 mites are 200 pieces

.

 

[Finman]

.

My opinion recarding with those few researches:

Final results vary quite much. Mortal rate of mites is not high enough and oxalic trickling is necessary to hit down the mite numbers before spring.

Formic acid is ment to kill mites that they do nut suck future winter bees.

Oxalic acid is ment to hit down that they cannot not multiply so much that they violate colony in late summer.


factors which have influence to final results.....

- the length of brood season
- treatment temperature, min-max
- number of treatment weeks
- bad luck


the dead rate 95% out of 1000 mites = alive mites 50
- 95% out of 50 mites .....................alive mites 2-3


When 50 and 3 mites douple itself monthly

1... 50
2....100
3....200
4....400
5....800 = critical level
6---1600

3 mites
1... 3
2....6
3....12
4....25
5....50
6---100

 

[boca]

Journal of Apicultural Research Vol. 43 (3) pp. 158 - 161
The there was a significant (r = 0.0181) correlation between formic acid mite mortality and temperature, but no such relationship (r = - 0.05) between mite mortality and relative humidity.

What could be the theory behind?
Hypothesis 1: the temperature affects the evaporation rate of FA and therefore the concentration of its vapor.

Hypothesis 2: the temperature affects the action of FA in the mite's trachea.

I have the feeling that #1 is the case.

 

[Hivemaker.]

The nassenheider evaporator is used by 15,0%.

And this is some imformation about the nassenheider.


The prototype of the "Nassenheider evaporator" was tested by Dr. Eva Rademacher, a beekeeper... B. Polaczek and Prof. B. Schricker, Department of Zoology, Free University of Berlin, Königin-Luise-Str. 1-3, D-14195 Berlin, Germany. Here follows the report in parts:

Application of formic acid by means of a specially designed applicator (evaporator) results in an elimination of more than 90 per cent varroa mites without the mischievousness (problems) like loss of queen or hatching (emerging) honey bees and incalculable variations of efficacy.

The applicator was tested in two, steps:
I. Colonies in one-story-hives single brood box, standardized as to size quantity of bees and brood, were tested comparably. Aiming for to establish the effect of formic acid on bees and mites (free and in capped brood-cells) in July and September. Furthermore, the minimal effective dose was determined in September.

II. Regular colonies in two-story-hives as kept in apiaries were tested in order to determine a practicable procedure of treatment recommendable to the beekeeper. These tests were carried out from September until the end of the breeding season.

Results
I. Standardized colonies (one story)

The amount of formic acid evaporated per 24 hours is presented separately in tests during July and September... Evaporation of the total amount of formic acid took place within 4.7 days (mean). The daily evaporation averaged 18.3 g/24 hours with reaches (maximums) up to 30 g/24 hours within the initial three days. In September total evaporation took up to 13 days at a daily mean rate of 7.8 g.

The counts of dead mites from adult bees reached 89.0 per cent (min. 53.3 per cent, max. 97.4 per cent) during the month of July, and, 95.9 per cent during September (min. 84.6 per cent, max. 99.6 per cent), respectively. Mites parasitical inside of capped brood-cells were killed during treatment at a rate of 87.6 per cent during summer (min. 61.5%, max. 94.1%), and, 91.5% (min. 86.4%, max. 100%) during fall, respectively.

In summary: The acaricidal efficacy of formic acid on mites of all stages averages 88.9% in July and 95.7% in September. Sufficient results derive from dosages of > 15 g/24 hours during summer and from > 6 g/24 hours during fall.

Determination of minimal dosage: For twelve days each one-story-colony was provided with an applicator containing 85 g of 60%-formic acid which evaporated from a felt area of 9 cm2.
The total amount of acid evaporated during this period of time differed. It averaged only 3.93 g/24 hours (min. 2.22 g, max. 5.3 g).
At this rate mite mortality was considerably lower and insufficient: Mean is 50.3% (min. 13.4%, max. 90%).

II. Not standardized-colonies (two stories)

The daily average was 17.5 g (min. 10 g, max. 34 g). The time span of treatment averaged 11.6 days (min. 5 days, max. 11.6 days).
The drop of dead mites averaged 94.3%, max. 99.8%. In 40% of the colonies > 98% of the mites where eliminated. A dosage of > 12 g/24 hours resulted in a efficacy of > 85%. This is in confirmation with the results obtained from standardized one-story-colonies (> 6 g/24 hours).

Calculated over the period of treatment the amount of evaporated formic acid per 24 hours should not be lower than 12 g/24 hours.
Damage on workers or queens was not observed in both (either) series of tests. The bees were hardly disturbed even at the beginning of the treatment, and they scarcely clustered in front of the hive. They did not hesitate to build combs incorporating the applicator. Mortality of bees was extremely low and peaked in one case at 6 bees during the period of treatment. This means a mortality of about 0.03%/colony.

Discussion

The results presented prove a successful and very effective application of formic acid by using an evaporator as described. Due to a soft, but steady evaporation of formic acid an otherwise experienced loss of queens and worker bees is avoided.
The dosage to be evaporated per 24 hours and hive-story should range between > 6 g and 10 grams. The total amount of formic acid should be applied over a period of about 10 days and be 85 grams per story.
Due to its efficacy on mites even in capped brood-cells formic acid can be applied right upon final removal of the honey combs, thus initiating the development of healthy winter bees. A treatment upon final removal of honey combs and repeated in September should be efficient to secure the survivability of the colonies. As to this a long term test is under way.

 

[winmag270]

Albion chemicals in Bristol

They would now be found by googling "Brenntag"

http://www.brenntag.co.uk/en/

Albion ceased to exist a number of years ago....

 

[boca]

http://www.medwelljournals.com/fulltext/?doi=javaa.2011.1106.1111
Efficacy Levels of Organic Acids are Used for Controlling Varroa (Varroa jacobsoni Qudemans) and Their Effects on Colony Development of Honey Bees (Apis mellifera L.)

The highest organic acid efficiency was achieved in the oxalic acid group in autumn when brood production was minimum and in the formic acid group in spring when brood area was maximum.

All the research I found measures the overall reduction of the number of mites, not the mortality of the different development stages of the mite.

I don't have the proof, but I have the feeling that FA affects mainly the mite larvae under the capping, and not the adult mite.

 

[Finman]

.
Hivemakers text is good. If you want to clean for example a swarm in 24 hours, it needs a 6-10 g dosage.
Is that right?

64% formic acid's specific gravity is about 1,15.
80% is 1,18

 

[BBG]

Finman or Hivemaker, anyone, is there a Youtube on this please.

We would like to see it in action so to speak.

We were two weeks later than the other hives with thymol treatment on our biggest hive. So sad.

The surviving few and the Queen are now in a Kieler at the front window under observation.