---------------------------- Forwarded with Changes ---------------------------
From: Max Watkins at GBCBC001
Date: 1/19/97 3:40PM
To: [log in to unmask] at INTERNET1
To: [log in to unmask] at INTERNET1
Subject: Re[2]: eradication of Varroa
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Apologies if you get this twice - I got a system error notification when I first
sent it.
Max
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Subject: Re[2]: eradication of Varroa
Author: Max Watkins at GBCBC001
Date: 1/19/97 3:40 PM
James, I agree entirely. Tropilaelaps has been know as a pest in Asia
for such a long time - many reknown bee experts have documented the
biology and control, notably Dr Woyke of Poland.
However, I do have one additional comment on the resistance issue
touched on by Dr Rodriguez: In areas where mite resistance to
acaricides is an issue (and remember this is still restricted
geographically - we are monitoring extensively) I don't see an
alternative to Integrated Pest Management. Widespread selection of
varroa-tolerant Apis mellifera is still in its infancy and is not yet
applicable as an effective control measure. For now, where natural
infestation and reinfestation levels are high, beekeepers will need to
use some form of chemical treatment, be it synthetic acaricides,
essential oils or organic acids, perhaps in addition to biomechanical
means, to control Varroa.
Where there is no indication of acaricide resistance - ie most of the
world at present - lone chemical treatments can still be used to
control Varroa, providing treatment periods are short and the
acaricide has a high efficacy. Where a professionally produced and
commercialised product is used, the label directions should be
respected - these instructions have been developed through thorough
testing of the product in various conditions.
Even so, it is advisable to employ two [or more] different modes of
Varroa control to prevent or at least postpone the evolution of
resistance. eg drone & brood management + an acaricide. This will help
prolong the lifespan of the arsenal which is needed to control this
pest. Noone wants to lose a useful tool; as an industry we need to
eliminate the hap-hazard mis-use of hive treatments in favour of a
sensible integrated approach using legal, tried and tested methods for
the benefit of all our bees.
Max
Dr Max Watkins
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Subject: Re: eradication of Varroa
Author: [log in to unmask] at INTERNET1
Date: 1/17/97 5:42 PM
Dr. Pedro Rodriguez wrote:
>As the rest of the world will soon discover, there is another mite in
India which has now
>claimed Apis mellifera (Italian race) as their choice meal.
Parasitism of A. mellifera by Tropilaelaps is very interesting and
important, but it's hardly a new phenomenen in India or elsewhere.
>The breeding rate of mites is so short and numerous that they really
>pose an enormous challenge to scientists to overcome.
Well perhaps ... but surely the obvious fact about V. jacobsoni is that its
reproductive rate is extremely low in comparison with most other mite
parasites and pests . This is actually an enormous point in favour of
control.
>Hence, the most plausible avenues of conquest of these mites is through
interruption of
>their life cycles with aims at erradication.
Surely this is an enormous non-sequitur. Yes it is logical to interupt the
mites life cycle - any method of control that doesn't do this isn't a
method of control at all, after all; but it does not follow that because
the mites are a big problem and because they can breed we must totally
eradicate them to be able control them. Moreover, even if eradication seems
an attractive idea, in reality it just isn't feasable since any eradication
scheme would have to reach every single mite in every single colony to be
a success. I'm sure that this point has been made enough times here before.
>Chemically, we already know that it can not be achieved because of the
mites ability to mutate and
>develop resistance to chemicals (the fluvalinate story). The solution
>lies in the utilization of physiological, anatomical and biological
>characteristics of mites.
It is a problem that mites can develop resistance to chemical treatments
used to control them. But rather than throwing our hands up in despair, it
is worth remembering that as beekeepers we can prolong the useful life of
the chemical treatments that we are using by strictly adhering to the
label directions so that we avoid exposing mite populations to sub-lethal
doses of the active incredient as it is this which is the factor most
likely to cause the development of resistance. I do agree that the long
term solution will probably not be based on chemical treatments, and this
is one reason why management methods (such as drone trapping) are
significant.
Finally, although the term chemical treatments tends to be associated with
synthetic pyrethroids etc., the 'alternative treatments' sometimes used by
beekeepers such as essential oils, formic acid and mineral oils(!) are
chemicals too. Their modes of action may be different, but I am aware of
no scientific reason that why the same issue of development of mite
resistance does not apply equally to these. Perhaps those better informed
than me in this field might wish to to comment.
Anyway, I should say that I am quite looking forward to receiving details
of Dr. Pedro Rodriguez's methods and results to consider.
James Morton
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