Recent questions about the proper use and improper reuse of Apistan(R)
prompted me to peruse the BEE-L archives, where I found the following
posts from Malcolm Sanford and Jerry Worrell. Deja vu, all over again!
Florida Extension Beekeeping Newsletter
Apis--Apicultural Information and Issues (ISSN 0889-3764)
Volume 13, Number 2, February 1995
Copyright (c) 1995 M.T. Sanford "All Rights Reserved"
...
FLUVALINATE--USE IT RIGHT OR LOSE IT!
It is now official! Resistance to fluvalinate, the active
ingredient in Apistan(R), has been found in Varroa mites.
This was published in the February 1995 issue of Bee Culture
(Vol. 123, No. 2, pp. 80-81) in "9th International Congress
of Acarology," by E. Sugden, K. Williams and D. Sammataro.
According to these authors: "The most ominous report came
from Dr. Roberto Nannelli of Italy. He has found areas
where Varroa mites are over 90 percent fluvalinate-
resistant, and his claims have been confirmed by German sci-
entists."
Oscar Coindreau, representative of Sandoz Agro, the company
that makes Apistan(R), also verified this report at the re-
cent meeting of the American Beekeeping Federation in
Austin, TX. He indicated that resistance was patchy in
Italy, but in certain areas, Apistan(R) provided no control.
And it doesn't take much resistance before Apistan(R) loses
its effectiveness, according to Mr. Coindreau, because any-
thing less than 99 percent control, is in reality, no con-
trol. That's because mite populations tend to bounce back
so readily in populous bee colonies.
All investigators indicate that the cause of this resistance
is not Apistan(R), but beekeepers' misuse of other formu-
lations of fluvalinate. In Europe the product is called
Klartan(R) and in the United States, Mavrik(R). All agree
the use of these chemical products soaked into wooden
strips, cardboard, paper towels, or in some cases, simply
sprayed into colonies, is a certain recipe for developing
resistant Varroa mites.
Although considered "ominous" in Europe, in the United
States resistant mites mean disaster. That's because most
other countries of the world have alternative treatments
that are legal. According to the authors of the article:
"In general, European scientists felt that the best way to
slow development of resistance in the mites is to have at
least two types of treatment which could be applied alter-
nately." This advice is mirrored in many other situations
where possible resistance in organisms to pesticides and an-
tibiotics exists (see "When Bugs Fight Back," APIS, Vol. 12,
No. 11, November 1994, which follows this article). It
turns out that some European countries even have three
Varroa mite treatments to turn to, rotating Apistan(R) with
formic acid and amitraz.
In contrast to those in Europe, United States beekeepers
have only one legal treatment, Apistan(R). The only other
candidate treatment at the moment in the United States is
formic acid. Although generally effective, there can be
many complications in using this product, including, queen
and worker loss even when applied correctly. It is also
caustic, one reason it is not looked on favorably by regula-
tory officials. According to one German researcher, efforts
need to be increased to develop a formic acid-based product
that is safe and foolproof, and can be registered quickly.
The authors of the article, therefore, conclude: "It may
not be a question of 'if' but only 'when and where' the
first super-Varroa mites will show up in North America.
This should serve a warning to all beekeepers to use control
methods only as directed on their labels."
The best way to ensure killing as many mites as possible
without developing super Varroa resistant to fluvalinate is
to use Apistan(R) right and only once. This philosophy,
along with proper application recommendations, was published
in the fall 1994, Apiculture Newsletter, published by the
Ontario Ministry of Agriculture, Food and Rural Affairs,
Guelph, Ontario, Canada. Here is what the authors (G.
Grant, and M. Nasr, in consultation with L. Goczan of Sandoz
Agro Canada) say in their article "Apistan Strips - Use'em
Right, Use'em once!":
"Apistan(R) is a plastic strip that contains a miticide,
fluvalinate. Fluvalinate is a contact poison that kills
Varroa mite. But Varroa mites must contact the right dose
before they die.
"Fluvalinate does not mix with water, but it does mix well
with oils and waxes. As bees walk over the strip, the
fluvalinate moves into the oils found on the surface of
their bodies. When bees contact each other in the hive, the
miticide is passed on. In a matter of hours all the bees in
the hive are covered with fluvalinate. Adult mites that
contact these bees will be killed by the miticide.
"As fluvalinate is picked up from the surface of the strip
the concentration drops. More fluvalinate then moves out
from the center of the strip to the outside surface. The
strip is designed to deliver the correct amount of miticide
to the surface over the 42-day treatment period.
"Eventually most of the fluvalinate is removed from the
strip -- the strip is spent. There is no longer enough
miticide left in the strip to kill Varroa mites....
"Why a 42-day treatment period? Worker bees take 21 days to
develop from egg to adult. Drones need up to 24 days to de-
velop. By leaving the strips in the hive for 42 days or two
worker bee generations, all adult mites and their matured
offspring will be exposed to the miticide. Remember, the
mite must contact the fluvalinate in order to be killed.
Mites in capped brood cells escape exposure until they
emerge from the cell with the adult bee.
"Why not leave strips in over winter? Because two potential
problems might occur:
1. Residues- fluvalinate mixes with oils and waxes. Leav-
ing strips in over winter might result in a build up of
residues in the wax.
2. Resistance- mites are not equally susceptible to
fluvalinate. Leaving mites in contact with spent strips
may kill the most susceptible mites, leaving the more
resistant mites to reproduce in their place."
"Use one (1) strip for every five (5) frames covered by bees
in brood boxes. Some strong hives may need three strips,
some weak hives will only need one. Place strips down be-
tween the frames so that they contact each side of the clus-
ter. The average hive will likely need two.
"Can Apistan strips be reused? No, with one exception.
There is no sure way of knowing if enough fluvalinate re-
mains in a strip to guarantee that it will work a second
time.
"The exception: If the strip was used once, only for three
days to detect mites, and if the strip was then stored prop-
erly between use, you might reuse the strip. You might re-
use it for either detecting mites for a 3-day period or for
one 42-day treatment.
"Store strips in a cool, dry and dark location wrapped in
aluminum foil in an air-tight bag. Avoid direct sunlight.
Don't store strips near chemicals or pesticides. Don't
store strips where they could contaminate food, feed or wa-
ter.
"In Ontario, Apistan(R) is registered as a Schedule 3 pesti-
cide. As with other 'homeowner' products, strips are ap-
proved for disposal in municipal landfills. Some
municipalities have their own special requirements for dis-
posal of Schedule 3 pesticides."
In the United States, the instructions on the label are the
law. They must be followed, even if varying from what the
authors say in the above article or other writings on the
subject. In addition, when applying Apistan(R), or any reg-
istered chemical, the person must have in his possession a
copy of the label.
Thus, when it comes to Apistan(R), the old adage, "use it or
lose it," must be modified. If U.S. beekeepers are to maxi-
mize the utility of the one legal and effective treatment
they have for Varroa, what many consider the most dangerous
organism affecting beekeeping today, they must "use it right
or lose it."
>-------------------<
Jerry Worrell <[log in to unmask]> of Dunkirk, MD posted
the following from the newsletter of the Pierce County
Beekeepers Association, concerning the reuse of Apistan
strips. Those who have reused Apistan strips in the past
may want to rethink that strategy.
Reuse of Apistan
Several persons have reported the reuse of Apistan after
some modification of the surface of the strip. Testing of
this method produced the following results:
* New Strips = 809 ug of fluvalinate on surface
* Visibly clean strips after 45 days of use = 201 ug (24.8%)
* Slightly contaminated strips after 45 days = 142 ug
(17.6%)
* After 45 days: brushed with electric wire wheel = 110 ug
(13.6%)
* After 45 days: planed on each side of strip = 70 ug (8.7%)
* After 6 months use (over winter) = 38 ug (4.7%)
Obviously using the strips beyond the 45 days required on
the product label significantly reduces the amount of chemi-
cal available to kill mites. Altering the surface of the
strips actually reduced the amount of chemical available.
Having low, sub-lethal levels of chemical in the presence of
an organism raises the opportunity for the development of
resistance to the product. Any reuse of Apistan is prohib-
ited by the label and now we know it is counter productive
and may produce Varroa resistance to fluvalinate.
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