Jump to content

Varroa resistance to Oxalic


Recommended Posts

  • Replies 61
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Popular Posts

tests where bees were fed OA are simply irrelevant.   Oxalic acid vaporization was already used in the soviet union and continues to be wideley used by many beekeepers in europe. Italy Austr

I can't believe you lot who have given this a "funny". I'm serious. The attitude is the root of a heck of a lot of trouble in the world.

A despicable way of referring to fellow humans.

2 hours ago, yesbut said:

Interesting bit of reading here....long story short, Varroa treated continously for 8 years with oxalic were still susceptical to it.

Goody, it means I don't have to feel guilty about not varying my treatment regime for a while yet !

 

https://www.researchgate.net/publication/311909899_The_susceptibility_of_Varroa_destructor_against_oxalic_acid_A_study_case

This is a very important issue
Human nature will ensure that OA at a few cents a dose will get disproportionate use in the future 
This could be a disaster should OA be susceptible to resistance 

Edited by Philbee
  • Agree 1
Link to post
Share on other sites
1 hour ago, Philbee said:

This is a very important issue
Human nature will ensure that OA at a few cents a dose will get disproportionate use in the future 
This could be a disaster should OA be susceptible to resistance 

Uh Huh .... there's always a curved ball to keep you on your toes.

What also is of interest is that over that last week or so of pulling strips, the amount of hives that have wingless bees, low PMS and dead bees that never emerged from the cell.

So .... was the apivar not effective,or was the mite loading so high it was'nt as effective as it should have been.

On the upside, it was pleasing to note that the vast majority of the hives had lots of bees in them.... many more than we have usually seen at this time of year. Is that because we did'nt use bayvarol this autumn, or that we put o/A cloths in as we supered up ?

Link to post
Share on other sites
7 hours ago, jamesc said:

was the apivar not effective,or was the mite loading so high it was'nt as effective as it should have been.

I'm pretty sure apivar and bayvaroll are contact killers. The mites that are sealed in the cell with the emerging bee are safe to do the damage until the bee emerges. 

Link to post
Share on other sites
20 hours ago, yesbut said:

Varroa treated continously for 8 years with oxalic were still susceptical to it.

In 'continuous' treatments I'm less concerned about the mites; more concerned about the 'bees. Eight treatments of 4%sol per year seems a lot. For example:

 

Higes, M., Meana, A., Llorente, J., & Suárez, M. (1999). Negative long-term effects on bee colonies treated with oxalic acid against Varroa jacobsoni Oud . Apidodologie, 30, 289–292.
Abstract - Two oxalic acid treatments were given to five colonies in autumn and five colonies in spring. In each treatment, colonies were treated every 7 days for 4 weeks with a 3 % sprayed oxalic acid. Another five colonies in each season served as controls and were sprayed only with water.
Efficacy of oxalic acid in autumn was 94 % and in spring was 73 %. A long-term study of the colonies for 3-4 months after the last application of oxalic acid showed a statistically significant negative effect of the acid on brood development. In addition, three queens died in the treated colonies.

 

Rademacher, E., Harz, M., & Schneider, S. (2017). Effects of Oxalic Acid on Apis mellifera. Insects, 8(84). https://doi.org/10.3390/insects8030084
Our aim was to define the no observed adverse effect level (NOAEL) and the lowest observed adverse effect levels (LOAEL) for OAD, including a safety margin for the dosage used in practical beekeeping. Furthermore, we wanted to understand which sublethal effects can be found and how OAD is distributed in the colony.
Two honey bee nucleus colonies (A. m. carnica) were used for a distribution test with a macro-computed tomography scanner (macroCT) where OAD (Oxalic acid dehydrate) was mixed with the water-soluble contrast agent Unilux.
After oral application, bee mortality occurred at relatively low concentrations (No Observed Adverse Effect Level (NOAEL) 50 µg/bee; Lowest Observed Adverse Effect Level (LOAEL) 75 µg/bee) compared to the dermal treatment (NOAEL 212.5 µg/bee; LOAEL 250 µg/bee). The dosage used in regular treatment via dermal application (circa 175 µg/bee) is below the LOAEL, referring to mortality derived in the laboratory…OAD used to treat varroosis of A. mellifera shows a rapid and consistent distribution in the colony for at least up to 14 days, and high efficacy against the mite, but also lethal and sub-lethal effects. In practical beekeeping, appropriate use of OAD (one topical application, on average 175 µg/bee) is relatively safe for A. mellifera at the colony level, even when some individuals are lost. However, ingestion leads to high mortality.
OAD is one of the most important organic acids used for the control of V. destructor. It is indispensable but must be dosed precisely and applied as seldom as possible to prevent sublethal damages which eventually lead to the loss of bees. Long disposition in the bee hive can cause accumulation of the acid and therefore induce further damage.

 

Strachecka, A., Paleolog, J., Olszewski, K., & Borsuk, G. (2012). Influence of Amitraz and Oxalic Acid on the Cuticle Proteolytic System of Apis mellifera L. Workers, 821–832. https://doi.org/10.3390/insects3030821
Oxalic reduced the activity of anti-pathogen cuticle barrier leaving the bees more susceptible to bacterial and fungal pathogens… The rinsings from the body surface of workers in the control group showed activity in relation to all the microorganisms. In bees treated with amitraz and oxalic acid, no activity towards A. niger or S. aureus was observed. Moreover, after applying oxalic acid, no activity was identified in relation to S. typhimurium or P. aeruginosa.

 

Nanetti, A., Bartolomei, P., Bellato, S., De Salvio, M., Gattavecchia, E., & Ghini, S. (2003). Pharmacodynamics of oxalic acid in the honey bee colony. Standing Commision on Bee Pathology.
…a noticeable contamination of the adult honey bees was detected 24 hours after the 1999 treatment. One day later the peak reached a maximum of 118 µg/g, but further remarkable decreases occurred on the seventh and on the eleventh days when contents of 10,8 and 2,0 µg/g were found. If an average honey bee weight of about 100 mg is taken as a reference, the individual oxalic acid contamination ranged around 12 µg, 1 µg and 0,2 µg, respectively. Further gradual decrease occurred during the following months… In the second replicate the presence of 14C-oxalic acid could be demonstrated in the honey bee haemolymph. The highest value (10 ng/mg) was recorded 12 hours after the treatment, but a steep decrease occurred further, leading to a concentration of 1,1 ng/mg on the 84th hour. Radioactivity almost completely faded out about one month after the treatment.
Little difference, if any, was shown by the autoradiographies of unwashed wings and of the wings where oxalic acid was removed by thorough washing. Both left clear impression of their nervatures on the film. This seems to indicate a low external contamination of the bees and is consistent with the detection of contaminating oxalic acid in the haemolymph, which fills the wing nervatures.
.. Twelve hours after the treatment, all the tracts between honey sac and rectum showed the presence of the marker, but later on only occasional presence of the radioactive marker was detected within the honey sacs. Generally the contamination decreased with the time; the intestines collected on the 22nd and 31st days were not contaminated with detectable amounts.

 

  • Like 1
  • Good Info 3
Link to post
Share on other sites

I have been told by someone who should know that oxalic kills mites in a manner similar to dropping a large anvil on your head from 10 m up. In theory anyway they will not become resistant. The research showing long-term damage from oxalic acid to the bees is a lot more worrying and it will be interesting to see how the bees from those who have thrown it around with gay abandon come through in the spring. Mind you given the glowing reports most oxalic users have been giving you have to wonder just how accurate some of that research was.

Link to post
Share on other sites
1 hour ago, john berry said:

I have been told by someone who should know that oxalic kills mites in a manner similar to dropping a large anvil on your head from 10 m up. In theory anyway they will not become resistant. The research showing long-term damage from oxalic acid to the bees is a lot more worrying and it will be interesting to see how the bees from those who have thrown it around with gay abandon come through in the spring. Mind you given the glowing reports most oxalic users have been giving you have to wonder just how accurate some of that research was.

Or the number of advertorials are posted.

  • Haha 2
Link to post
Share on other sites
1 hour ago, Dave Black said:

In 'continuous' treatments I'm less concerned about the mites; more concerned about the 'bees

Unless I'm mistaken, the effect on the bees is limited to the  individuals being subjected to the oxalic, there's no evidence of intergenerational effect ? 

 

Link to post
Share on other sites
1 hour ago, john berry said:

oxalic kills mites in a manner similar to dropping a large anvil on your head from 10 m up

Not big on the anvil hypothesis myself. ?

Oxalic acid is found in many living things; pretty ubiquitous. It is an inescapable part of their metabolic processes, even if they didn’t eat it they would make it, just like us. Consequently, nearly everything has a way of getting rid of it. Sometimes this is quite ingenious, some plants produce spiky calcium oxalate crystals that make their leaves unpleasant to eat for example. Sometimes it’s just converted to carbon dioxide and water or passed as is. People make kidney stones if they have trouble getting rid of it. Goats have gut bacteria that help if I remember right, so they can eat some pretty inedible plants. Or, to put it another way, almost everything is probably resistant to oxalic already.

I suspect it’s not what it is, but how much of it you get relative to an ability to process it that leads to trouble. In just the way that bees tolerate it, mites could, if they didn’t get such a humungous dose. Until we know how it works, we can’t make sensible guesses. I think the smart money reckons it isn’t acidification of the bee’s haemolymph, because it isn’t a big enough change in pH. It appears to act directly on the mite, perhaps through its feet. Maybe it interferes with calcium ion use and limits energy production, who knows, the possibilities are many, both crude and subtle.

  • Like 2
Link to post
Share on other sites
16 minutes ago, yesbut said:

there's no evidence of intergenerational effect ?

Nope, unless you mean the next generation becomes contaminated by residue from the treatment too. Most of it has gone in a fortnight, but a little remains up to a month, and a tiny bit a little longer. If you dose once a week, you will have more in the hive than you think.

Link to post
Share on other sites

The three Queen deaths from 5 hives cannot be taken seriously.
Ive deliberately overdosed test hives so as to cause substantial wetting and death to 1-2 cups of Bees at the hive yet the Queens  live on.

This treatment while new to most has seen use in my Hives beginning last Autumn, through Winter, this Spring Summer, Autumn and now into Winter.

I do not  lose Hives to Varroa any more and I dont see PMS ever.

I contacted a world Renound bee Researcher two weeks ago about the possible effects on the Bees from ingesting OA and his reply was that when in a cloth or contact delivery form , his studies have shown that the Bees will not ingest either OA or GL because they are adverse to it.

Remember that the systems being studied here appear to be dribbles and in syrup.
Both these methods expose the bees to relatively high doses of OA.

If a OA /GL Staple in a hive is still active after say 4 months, this would suggest that the dose from that Staple is administered over a long period so therefore relatively low.

IMO the future will see the doses lowered considerably by reducing the concentrations of OA in the GL, possibly down to 20% and the better the slow release mechanisms are, the more control available.
 

  • Like 2
  • Agree 1
Link to post
Share on other sites
1 hour ago, glynn said:

Oxcalic and glycerin strips have been used in South America for over 10 years with no resistance found and the strips use quite high levels of oxcalic acid 

Another point made by my researcher contact was that the regulating food authority were not at all interested in looking at the Glycerin component of the treatment in the approval process  

Link to post
Share on other sites
47 minutes ago, Philbee said:

Absorbed?

Im not a chemist and dont know how if at all it would be held in the wax or in what state
 

I have read that beeswax had traces of the synthetic pesticide in it when tested.

So there wax must absorb that .

I don't know either.

Link to post
Share on other sites
9 hours ago, Christi An said:

The only real drawback to OA is that it doesnt generate as much revenue for the chemical corporations as the synthetics. Keep that in mind when reading reaearch about it.

 

This is a very good point and is now plain to see 
To treat a two box hive in a way that is without compromise  costs a maximum of approx $3.00-$3.50  per hive plus  the labor content of mixing up the Acid and placing the strips.

The Labor cost is small but to mix enough Solution to make say, 10000 Staples (2500 single box hives) will take several Man/ Days 

or about 50 cents a single box hive 
What this does is create a viable job for a Labor unit or two during slow periods, like now for example.

  • Like 3
Link to post
Share on other sites
11 hours ago, Christi An said:

spraying (solutions from about 2% will work.) the water will quickly evaporate leaving tiny OA crystals on the bees.

Good stuff Christi, 

 

I have read some info on Mr Oliver site, and spraying a mix off ox on bees can be very harmful.  A lot worse than dribble.  Though I expect he may have used a stronger mix ratio.  Anyone thinking about spraying bees needs to get full information;  

Do you think it possible that ingested oxalic (via dribble) could end up in the bees blood, then as the mite drinks the blood they die? 

Link to post
Share on other sites

Regarding the OA strips i have not done as much research as this method is not currently used in Germany. As far as i know it is still at a very experimental stage with many beekeepers steadily trying to improve the formula. I personally would wait till it is more wideley used and then check the experiences.

 

I would assume though as opposed to vaporization, having strips of OA and glycerene in the hives for a long time will tempt the bees to remove them by chewing. This might cause them to ingest some of the OA which seems to cause problems. Nevertheless if you keep the treatments at a reasonable level you should not get any real problems with any form of treatment.

 

However do not forget that also the synthetic miticides are far from harmless to the bees.

 

OA in the bees blood will to my knowledge not be harmful for the mites (check Randy Olivers articles regarding that matter)

OA serves as a contact poison to my knowledge.

 

Regarding the harmfullness of spraying heres a nice read:
https://www.apidologie.org/articles/apido/full_html/2010/06/m09055/m09055.html. Even solutions of 0,5% are toxic to varroa mites.

 

most formulas are too highly dosed (also the commercial ones you get for example in Germany) 

  • Like 1
Link to post
Share on other sites

@Christi An the reason I am interested in OA in wax is because I am going to make some wax food wraps with my wax.

I had only foundation frames at the beginning of the  honey season and they went on after the Apivar was taken out .

All the wax I collected was from the scrape and strain honey frames.

So except for the OA the wax should be chemical free.

Link to post
Share on other sites

×
×
  • Create New...