In all scientific papers and official recommendations of the beekeeping communities in the USA, Britain, Spain and other countries there are tables with recommendations at what quantity of Varroa mites on a sticky board, and at what percentage of colony infestation by Varroa mites, certain measures must be taken in order to combat mites that infect this family of bees. Sometimes it is just a continuation of monitoring the colony, sometimes it is suggested to carry out treatment after an interval of 2-4 weeks, sometimes treatment is required urgently ... It all depends, of course, on how severely the colony of bees is affected by Varroa mites.
But, unfortunately, these tables do not quite correctly describe the situation that takes place in a colony of bees affected by Varroa mites. We have learned this from our sad experience, working with control families in our experimental apiary.
The mistake here is that these tables show the values of infestation, as it were, in development - spring, summer, autumn. And it seems that if in the spring the percentage of colony infestation on the basis of an alcohol wash is set at 1-2%%, then it seems to the beekeeper, and sometimes such a table directly says, that there is no need to do anything in the next 3 months. This is completely wrong and this is a big mistake. If we take a family that will not be subjected to any chemical treatments, then we can say with confidence that the growth of Varroa mite population is 2 times a month. This is scientific evidence and we have also seen this in our experimental families. The experiment involved 7 families, and the results fell into this graph with high accuracy.
The theoretical graph starts with the percentage of colony infestation equal to 1%, the real schedules of families have their own, sometimes unknown values of the percentage of infestation at the initial stage. However, they all repeat the trend of the monthly doubling of Varroa mites population with high accuracy !!! Family number 7 at the end of October is still alive, but its size is not very large. It occupies approximately 5-6 streets in the Dadant system hive. This family differs in that at the beginning of summer there was formed one offshoot from it, consisting from 3 frames of brood, after that, when changed the queen, she did not lay eggs for about 1-2 weeks, then 2-3 frames of new brood were selected one by one to increase offshoot. These operations led to the removal of part of the Varroa mites from the colony and to decrease of its general infestation. By the way, the offshoot died in september... Nevertheless, despite the deviation from the theoretical schedule, the trend of recent months still corresponds to a doubling of the tick population.
Thus, infestation of bee family by Varroa mites equial to 1-3%% , which seems insignificant, is not insignificant at all! If you will make an alcohol wash in April, and you will see such a degree of infestation, then according to the forecast, you will get an infestation of 8-24%% in July, which is already very difficult for a bee colony, and in September - 32-96%%, and this already lethal for any family of bees!
If you found infestation in the amount of 1-3%% in September, after the end of egg laying by the queen, then you can be sure that the family will overwinter well and actively begin spring development. But it will begin its development along with the population of Varroa mites, although they will decrease by 15-20% during the winter!
Thus, it can be argued that the best time for any treatment is April-May, the time of the greatest increase in the bee colony and the most active growth of the mites population. At this time, it is good to apply a complete removal of earliest sealed brood and treatment of adult bees with appropriate preparations which the beekeeper prefer most of all. It is especially important to do this in advance because at the end of May-June and before the first ten days of July in the middle lane, the free fall of mites on a sticky board almost completely stops, which, as a rule, causes a certain euphoria among beekeepers. They believe that the mites are gone and the family of bees is healthy. But it's not so! It's just till this time the mites that have overwintered in the family of bees are almost completely dying out, and the young mites of this season, born in March, April and May, are young and healthy and will not die off soon.
Thus, we
consider absolutely fair (taking into account the acceptability for the
beekeeper of the very fact of chemical treatment of bees from Varroa mites) the
recommendation of American scientists to start processing bees from the moment,
when percentage of infestation reaches 2-3%%. And do it immediately upon
reaching values of 3.5-5%%, because this is a critical value, with an
increase of which the bee colony is already doomed to death. As we have already
said, this is especially true for spring and early summer, when Varroa mites
have several months ahead of them to intensively increase their population.
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