Spring use of Tylan for American Foulbrood raises residue concerns

For Canadian beekeepers considering using Tylosin to treat American Foulbrood in your honey bee colonies, you may want to read the following information, which comes courtesy of Gerry McKee, the president of the Canadian Honey Council.

As you read it, one important observation should spring to mind: even among scientists, researchers, beekeepers and bureaucrats there are divergent opinions about how and when chemical treatments should be applied to honey bee colonies, especially when they can leave a residue. The fact that all provincial apiarists and the federal government’s own chief bee scientist are suggesting the Canadian Food Inspection Agency’s recommended procedures are a concern simply reminds me that science and practicality of beekeeping continue to clash.

Here’s the note from McKee, in its entirety.

Tylan (Tylosin), made by Elanco Animal Health

Tylan (Tylosin), made by Elanco Animal Health

ATTENTION – CONTROL OF AMERICAN FOUL BROOD DISEASE

For you information,  Tylan® has been registered for use in Canada, with the inclusion of a proposed 0.2 ppm Maximum Residue Limit (MRL) of Tylosin, for use in controlling American Foulbrood (AFB) in honey bee colonies.  However, there is concern CFIA’s recommended spring treatment of adding it to syrup or as a sugar dusting may lead to higher than anticipated residues in the honey.

On behalf of all Provincial Apiarists, Geoff Wilson,  Saskatchewan’s PA, has requested, the Veterinary Drug Directorate and Elanco Animal Health, reconsider the spring treatment of Tylan as a sugar dusting and replace it with Tylan delivered in a pollen patty as recommended by Dr. Steve Pernal, Agriculture and Agrifood Canada, whose work has shown the application of Tylosin in a pollen patty is effective and greatly reduces the risk of residues.

Geoff Wilson’s request includes the following background information:

With the previous off-label prescription to control Oxytetracycline resistant AFB, which was used only in the fall, honey produced in the following season has been found to have residues of Tylosin.  These levels are below the proposed 0.2 ppm MRL but treatment in the spring will only increase the likelihood and levels of tylosin found in honey.  A three week treatment and four week withdrawal period before a honey flow will be very difficult to impossible for many Canadian beekeepers to fit into their spring management.   At this time of year, beekeepers would be pressed to do the treatments while attempting to maintain normal beekeeping practices.  It is also very difficult to accurately predict the start of honey flow in a given year and the first significant honey flow can vary by over a month in many regions.  In most cases a spring treatment will not be possible because of our compressed beekeeping season compared to the United States.  The most likely result will be insufficient withdrawal period and higher than anticipated residues of a very stable antibiotic.

Fall treatments intrinsically have far less risk of residues that could impact our honey market.  Experience in Canada has shown excellent AFB control with fall only treatment of Tylosin as a sugar dusting.  This in effect makes a spring treatment option unnecessary.  If, however, a spring treatment is thought necessary, a safer alternative is available.

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So, dear readers, what do you think? Do you use Tylosin/Tylan to control AFB, and if you do what do you think of Wilson’s and Pernal’s observations?

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