Tuesday, March 8, 2022

 


RELATIONSHIP BETWEEN WINTER FALL OF VARROA MITES, AND SURVIVAL OF BEE FAMILIES IN THE NEXT SEASON.

As you know, almost all beekeeping societies in Europe and the USA receive recommendations from specialists in the fight against Varroa mites about the quantities of Varroa mites, falling down on sticky board in bee colonies, which can be acceptable in spring time and in summer.

Figures vary from country to country, but in general, free fall of Varroa mites in spring and summer up to 5-10 pieces per day is considered to be acceptable. A mites drop of 25-30 pieces per day is considered to be critical. In our opinion, these figures are too optimistic. In addition, summer is not the most critical part of the season. Beekeeper has the opportunity to reduce the number of mites in one way or another by treating the bees with acaricidal preparations.

Winter season is a completely different matter ... The beekeeper does not have the opportunity to influence the condition of the bees and mites because of rather low temperatures, especially in regions with cold winters. At the same time, mites begin their breeding season in winter in the first, not yet mass, bee brood, which can appear as early as February-March in cold regions. At this time, the beekeeper can neither open the hive, nor carry out the treatment of bees against the mites. But, despite this, all the same, the beekeeper would like to know in what condition his bees are and what he should prepare for with the advent of spring.

In this, he can also be helped by counting of the mites falling on sticky board.

Our studies of free fall of mites in different seasons of the year and fixing what happens to bee colonies after that, showed the following patterns:

Families in which free fall of Varroa mites in winter did not exceed 0.5 mites per day did not experience serious problems until autumn. They gave honey, but approached autumn already with a large number of mites and were rather weak.

Families in which free fall of Varroa mites in winter was in the range of 0.3-0.6 and in any case did not exceed 1.0  mites per day, also experienced the summer season normally, although by autumn they came more weakened and with a big number of mites. Some of them died in winter.

Families in which free fall of Varroa mites in winter was in the range of 1-3 mites per day experienced serious problems already during the main honey flow and often died in July-August after the completion of the main honey flow due to the lack of an influx of young bees, which  died from viral diseases transferred by Varroa mites.

Families in which free fall of Varroa mites in winter exceeded 2.5-3.0 mites per day received serious problems already in April-May, that is, already at the beginning of the summer season, and often died or abandoned brood and scattered in several swarms.

Thus, we can say that control of the mites, falling on sticky board in winter and early spring, can help the beekeeper in assessing the condition of bees and the prospects for their development in future. This can also help to predict how a particular family will use the early and main honey flows. Moreover, such control does not disturb the bees, and can be carried out at any outdoor temperature and weather.

The number of falling mites must be counted for a certain time interval, which can be quite indicative - 14-21 days. Then you need to get the average number of crumbling mites per day. With this averaging, the results will be quite reliable.