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Author Topic: Can oxalic acid be used two times per year ( 6 months each ) ?  (Read 3661 times)

Offline ThomasGR

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Can oxalic acid be used two times per year ( 6 months each ) ?
« on: October 23, 2013, 08:24:49 am »
Hello,
I am going to overwinter bees for 3rd year and after keeping enough notes for my area, i am trying to make an annual program of actions and cost management. I do not transfer my hives. This winter during broodless period (Mid December - Early January ) will use oxalic acid as dribble. Is it ok to treat also with oxalic acid after summer harvest in Mid July and the again next December ? I often read a limitation of only 1 time per year. The bees will be completely different. What do you think ?
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Offline danno

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Re: Can oxalic acid be used two times per year ( 6 months each ) ?
« Reply #1 on: October 23, 2013, 09:52:19 am »
Your going to get some mixed answers on this subject.   Most will say no but be given by members that have never used the method but read about it.  A few will say yes because they do it.   I only do it once a year in Nov and vaporized or use something different in spring time.   If I were you I would ask Finski.   He is a member here and has the most experience on the subject.   

Offline Finski

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Re: Can oxalic acid be used two times per year ( 6 months each ) ?
« Reply #2 on: October 23, 2013, 10:04:44 am »
This winter during broodless period (Mid December - Early January ) will use oxalic acid as dribble.

That is OK. Further more you should treat the colonies in late summer when they rear winter bees. Stuffs are thymol or formic acid. They need about 17C day temps.
Oxalic is only one which works in under 15C temps

With my 10 y experience with trickling I can say that if that trickling is  only treatment, mites will kill quite big part of winter cluster bees before autumn.  Late summer treatment is much more important than winter trickling.


Quote
Is it ok to treat also with oxalic acid after summer harvest in Mid July and the again next December ? I often read a limitation of only 1 time per year. The bees will be completely different. What do you think ?

I do not think,  but I know.  Nowadays there are no limitation how many times a year you treat.

Oxalic trickling makes  big damages to the (winter )brood and it will be as bad as mite itself. Furthermore, it does not affect on mites under brood cappings.

The idea, that you need mite treatment after honey harvesting.... that is why is trickling. It gives the last hit on mites that they are very few when brood season begins.

In Finland most guys use thymol pads during winter feeding. It kills about 80% of mites and the rest you should kill with trickling.

This is a way how thymol pad works

« Last Edit: October 23, 2013, 10:19:58 am by Finski »
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Offline Finski

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Re: Can oxalic acid be used two times per year ( 6 months each ) ?
« Reply #3 on: October 23, 2013, 10:18:24 am »
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It is not rare that you notice during main yield that mite amount is too big in the hive. In this case make a hive queenless. Hive will forage normally and it does not harm your yield. Hive will make a emergency cells and new queen will emerge after 10 days.

When the colony has bees without eggs 2 weeks, make a false swarm and separate older bees and brood.
Move brood nest  10 feet away. Make a new hive into old site and let the bees return to their original site. After 3 days bees are in old site. Give trickling to them of formic acid treatment.

Let the brood hive emerge pout, and then kill the mites.
After killing join the hive parts to produce winter bees.


If you want good quality queens from emergency cells, change the larvae in cells. When the new virgin starts to lay, the hive is almost without brood. You may take the rest of brood off and treat the mites.

That way I saved my best hive last summer. It brought 180 honey and I got mitefree colony after procedure.

When the hive was queenless and without larvae, it brought 6 kg honey per day.

That hive had 7 boxes during main yield. In treatment it had 3 boxes.

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Offline Finski

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Re: Can oxalic acid be used two times per year ( 6 months each ) ?
« Reply #4 on: October 23, 2013, 10:22:10 am »
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In Greece and in Italy they seems to use 4% oxalic acid in trickling.

Most of Europe uses 3,5%.
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Offline ThomasGR

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Re: Can oxalic acid be used two times per year ( 6 months each ) ?
« Reply #5 on: October 23, 2013, 03:58:53 pm »
Thanks for the response.
I agree that late summer is critical period. Actually Late August - September is the period that i can see mites with my eyes. The low temperature is the info that i did not know. So during hot Greek summer oxalic is not an option at all. I want to treat mid summer to give enough time for a second harvest on October. What is the wait time for thymol pads before harvesting ?

Thanks
Thomas , Greece @ www.melikonitsas.gr | www.beephotography.org |Apiary Weather Station |[img width= height= alt=Image created by a PHP script" width="310" height="30
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Offline Finski

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Re: Can oxalic acid be used two times per year ( 6 months each ) ?
« Reply #6 on: October 23, 2013, 04:10:37 pm »
So during hot Greek summer oxalic is not an option at all.

Formic acid turns dangerous to queens if out temp is over 25C.
In hot weather thymol may bring problems too when stuff gasifyes too quickly.

Trickings has been invented by Italain professor Nanetti.
He has made oxalic researches in Greece too. Look from google.
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Offline Finski

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Re: Can oxalic acid be used two times per year ( 6 months each ) ?
« Reply #7 on: October 23, 2013, 04:14:09 pm »
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Efficacy of repeated trickle applications of oxalic acid in syrup for varroosis control in Apis mellifera: influence of meteorological conditions and presence of brood.

Bacandritsos N, Papanastasiou I, Saitanis C, Nanetti A, Roinioti E.

2007


Institute of Veterinary Research of Athens, National Agricultural Research Foundation, Neapoleos 25, Agia Paraskevi 153 10, Greece. bac.ivra@nagref.gr


Abstract


Oxalic acid field trails for the control of varroosis (Varroa destructor) were carried out in an apiary located on the Mt. Imittos (Attica, Greece). The colonies received four successive applications (approximately one every 16 days) with 4.2% oxalic acid (OA) and 60% sugar solution by trickling method with two alternative types of syringes (an automatic self-filling dosing and a single-use) from the broodright to broodless period. The results indicate that the first three applications (from 6th October to 25th November-broodright period) resulted in 65.3% cumulative mite mortality, while only the last application (after the 26th November-broodless period) resulted in 77.3% mite mortality. Very low outern temperatures reduce to the minimum the bee movability, which may result into a slower development of the OA efficacy. No poor colony growth or queen loss were observed even if the bee colonies were received the four successive OA applications with the last one taken place at a very low outern temperature (6.2 degrees C). The trickling method using an automatic-filling syringe seems to be a very quick way for applying oxalic acid in large apiaries (approximately 150hives/h).
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Offline ThomasGR

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Re: Can oxalic acid be used two times per year ( 6 months each ) ?
« Reply #8 on: October 24, 2013, 04:59:14 am »
Thanks for the articles. I found this article and one more from the sources that had answers.

They make more than 1 oxalic treatment ( 3 or 4 ) in very short periods. I was asking for 6 month period but it seems that its more than ok. Also treatments were made with high temperature conditions ( over 15c ) and resulted moderate mite fall. But this is ok for an action during the season that is really long in Greece where bees rearing brood for more than 11 months.

In
Biology and control of Varroa destructor
Peter Rosenkranza, Corresponding author contact information, E-mail the corresponding author, Pia Aumeierb, Bettina Ziegelmanna

says
"independent from temperature"
for oxalic acid
« Last Edit: October 24, 2013, 05:55:58 am by ThomasGR »
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Offline Finski

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Re: Can oxalic acid be used two times per year ( 6 months each ) ?
« Reply #9 on: October 24, 2013, 08:07:10 am »


They make more than 1 oxalic treatment ( 3 or 4 ) in very short periods.

It was test. Not recommended treatment.

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Offline merince

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Re: Can oxalic acid be used two times per year ( 6 months each ) ?
« Reply #10 on: October 25, 2013, 11:43:19 am »
As Finski mentioned, the trickle is not effective in getting the mites under the cappings. After the flow, the majority of the mites will still be under the cappings. I have heard some people suggessfully use the dribble as 4 treatments, 3 or 4 days apart.

Personally, I requeen after the flow with a queen cell. This gives the hive a broodless period which is effective in keeping mite numbers down. It works, because the mites flood the first brood the new queen lays and kill themselves and the the brood.

Offline Finski

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Re: Can oxalic acid be used two times per year ( 6 months each ) ?
« Reply #11 on: October 25, 2013, 12:18:28 pm »
I have heard some people successfully use the dribble as 4 treatments, 3 or 4 days apart.



Oxalic acid does not go that way.  It has been tested many times that oxalic trickling violates brood badly.

It has been very well verified after that when oxalic trickling was invented 1997 by professor Nanetti in Italy.

People tend to "invent" theirs own methods even if group of best researchers made hard work during years 1998-2003.

Thymol and formic acid evaporation is used in late summer after yield harvesting. Those too do not kill mites under cappings.

European Varroa Group sieved best methods from all known methods and it made its recommendations.
After that no remarkable methods have invented. Over 100 methods are known to treat varroa.

Switzerland has collected the results very well here

http://www.agroscope.admin.ch/imkerei/00316/00329/04435/index.html?lang=en


Honeybee has 32 pests and diseases. Now researchers try to take care of other diseases too, and not only varroa.
Quite few country have beekeeping researchers.
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