>> Breeding on natural varroa defense - was it an utopia? <<

From bee master Alois Wallner, 3263 Randegg
German version in the magazin "BIENENWELT" 1. January 2002

As a professional beekeeper with 700 bee colonies I must be concerned since the year 1985 with the parasite varroa mite. I call myself a pupil of Dr. Josef Bretschko, who died unfortunately so early. In the year 1988 when Dr. Bretschko recommended also different ways of varroa defense, I started with my independent way of defense: "selection and breeding on natural varroa defense".

Arrears-free wax
Because I only used formic acid for the annually varroa mite treatment, my entire wax is demonstrably arrears-free. Arrears-free wax is according to my opinion the basis for an objective and comparable selection on a measurable natural varroa defense of the individual bee colonies.

Review
In the year 1990 I self-published my book "Imkern heute" ("beekeeping today"); the book is unfortunately out of print. In this book I presented my method of the selection on killing varroa mites by the bees for the first time. Much criticism came over me from the various scientists. Even for April jokes one abused my work. Meanwhile however the waves smoothed themselves.

My value for the characteristic "killing varroa mites by the bees"
This value is measured daily on five days in September at the selected colonies. I investigate the injuries of the mites with a magnifying glass (20x enlargement) - usually there are injuries at the legs of the mites.

Example
Total mite fall-down of a colony in five days:

Total mite fall-down..............50 mites

25 mites of it with injuries result in a Varroa-Killer-Factor of 50%.

That means, that half of the natural mite fall down originates from bites of the bees, the remaining mites without injuries could further-increase until their natural death.

The more mites are killed by the bees in relation to the total fall-down the better is the Varroa-Killer-Factor.

With a laborious selection and breeding I could increase this characteristic in 13 years substantially.

The raise of the Varroa-Killer-Factor

Varroa killer factor of the breeded colonies per year:

1990........................... 27 %
1993........................... 52 %
1995........................... 75 %
1996........................... 84 %
1997........................... 84 %
1998........................... 89 %
1999........................... 89 %
2000........................... 90 %
2001........................... 90 %
2002........................... 92 %
2003........................... 92 %
2004........................... 92 %
2005........................... 93 %
2006........................... 95 %
2007........................... 96 %
2008........................... 96 %



How does this change in natural Varroa defense affect?
At an average value of more than 80%, I can give up the cutting of the drone brood. The offshoots do not have to be immediately treated against varroa. I also can give up the treatment in September. Only for the largest varroa pressure I treat twice a year with formic acid. The rest perfom the bees by themselves. All year round the mites were killed by the bees. A treatment in spring is therefore unnecessary. The varroa mite lost it's fright in my beekeeping. Arrears-free bee products, which correspond also to the biological standards, can be marketed. With the nature and not against it, is my guidance.

Made in Austria
Meanwhile is my method of the measurement of the characteristic "Killing of varroa mites" a component of the breeding standards of the German beekeeping federation.

Summary
Selection and breeding on natural varroa defense is very difficult and takes decades of hard work. One simple beekeeper cannot manage this work. The improvement of the natural varroa defense has very positively affected my beekeeping. Instead of four treatments, two are sufficient today; without cutting the drone brood.

In former times I had to treat the offshoots immediately, that became unnecessary, too. In former times I had to accomplish a last treatment in September, that is meanwhile unnecessary, too. The bees do it by themselves; by killing mites all year round, day and night. The treatment in spring is not necessary any more. The colony losses over the winter time are not higher than before the varroa invasion. I had only 1 percent winter losses in the previous year. Breeding on natural varroa defense was no utopia in my beekeeping.