Three studies for the list relating to recent posts.
Today someone asked if radioisotopes had been used to detect queens. There is a small short published study.
Nelson, D. L. and W. F. Baldwin. 1977. The use of radioactive platinum-iridium (IR-192) tags for locating honey bee queens in colonies (Hymenoptera: Apidae). Canadian Entomologist. 109: 319-320.
The introduction lists that a number of studies by where researchers have marked other insects with radioactivity to follow their movements. The introduction also cites a study where radioactive paint was used to mark queens, but it proved unsuitable. The study looked at fastening flattened platinum-iridium wires (1.5 x 0.5mm) to the thoraces of queens with a rubber adhesive. The specific activity of the tag was 25 microCi. The marked queens were put into 12 small nucs and their behavior and brood rearing was compared to that of 8 queens marked with nonradioactive tags in a separate set of nucs. After 4 weeks there was a trend towards smaller brood area among the marked queens, however the difference was not significant. There was no noticeable difference in behavior. A simulated test to compare how quickly queens could be located was done in supers without bees using the tag vs. visual inspection was done. An approximate 300% savings was realized in using the irradiated tags.
Although much more work was required to be done to investigate the safety, utility and economics of such a device for use by beekeepers, the work was discontinued, largely due to concerns by Canadian regulators of putting even such small amounts of radioactivity in a hive, where the tag could be lost and not be accounted for.
The next study was in response to the thread on antibiotic medication alone, as a tool to manage clinical symptoms of AFB:
Oldroyd, B.P., R.D. Goodman, M.A.Z. Hornitzky and D. Chandler. 1989. The effect on American foulbrood of standard oxytetracycline hydrochloride treatments for the control of European foulbrood of honeybees (Apis mellifera). Aust. J. Agric. Res. 40: 691-697.
Summary:
Twenty honeybee colonies were treated with various oxytetracycline hydrochloride (OTC) preparations at the time of inoculation with Bacillus larvae spores or after American foulbrood (AFB) disease signs had developed.
Treatment with 1g OTC, at the time of inoculation delayed the development of AFB disease signs in four hives for periods between 2 months and 1 year. One colony so treated did not contract the disease.
Colonies with a light AFB infection treated with 1g of OTC recovered from the disease in 3-4 weeks, but AFB disease signs reappeared in three of five colonies following season. Colonies with a well-established infection showed complete recovery from AFB disease signs after various OTC treatments. However, nearly all of these colonies developed disease signs in the following season.
B. larvae was cultured from adult bee samples from colonies that were AFB disease-free at the time of sampling but subsequently developed disease signs, and from colonies that were AFB disease-free at the time of sampling but did not subsequently develop disease signs.
The results show that recommended treatments for European foulbrood (EFB) effectively mask AFB disease, making it likely that beekeepers treating EFB also supress signs of AFB disease if it is present. As it is common practice in Australia to treat EFB prophylactically with OTC, an escalation of AFB in Australian hives is anticipated.
From that study I think it can be suggested that treating colonies with antibiotic, without taking any steps to remove diseased larvae, particularily when the disease is established, will not cure the disease. I do not believe this is inconsistent with Allen's experience. Allen medicates, but simultaneously does a good job of rewarding his crews to cull out any diseased comb they find in hives or in stacks of empty supers.
The final study is the work that got people thinking about using cupric sulphate in feed as a way to control varroa:
Guiraud, G., M. Nectoux, J-F. Andre, M. Bounias and D. Popeskovic. 1989. Evalution of cupric sulphate as an acaricide against Varroa jacobsoni O. J. Apic. Res. 28: 201-207.
Summary
Field trials on hives showed that cupric sulphate mixed at 0.25-1 g/l with sucrose syrup yielded significant control (>70% mortality) of the parasitic mite, Varroa jacobsoni, in low or moderate infestated areas, in spring-, autumn- and winter-feeding treatments. Pure sucrose may also exhibit a light effect (15-29% mortality). Syrups are freely injested up to 0.35 g/l and the uptake decreases at 0.5-1 g/l, with no uptake observed at higher concentrations. Only slight bee mortality (<0.1%) is observed at 1g/l (low volumes) or at 0.5 g/l (large volume). Copper residues in honey never significantly increased from natural levels, following total uptakes of up to 3g per hive, within 1 to 7 months delay.
I was excited to discover this research and this year we conducted a trial to investigate biweekly drenching of colonies with 1 liter of syrup containing 0.4g/l of cupric sulphate. The levels of varroa, unfortunately, were never different than that of colonies left untreated and were much higher than that of colonies treated with Apistan. I am not sure what was the cause of the discrepancy between our results and the results from France. Our work is still preliminary, however we expect to have it submitted to be peer reviewed for publication next year. For everyone's information, cupic sulphate is not registered for use as an acaricide in North America and there have been no trials in North America, that I am aware of, that indicate that it controls mites, is safe for bees and leaves no residues in hive products.
Regards
Adony
Adony Melathopoulos
Apiculture Biotechnologist
Agriculture and Agri-Food Canada
Beaverlodge Research Farm
Box CP 29
Beaverlodge, Alberta CANADA
T0H 0C0
T +1 780 354 5130
F +1 780 354 8171
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