Treatment for varroa mites schedule using Varroa Terminator device
Since we have Varroa Terminator as a tool to get rid of varroa mites on bees and brood, it is necessary to know when to use it.
The principle of a successful varoosis management consists of keeping it at a rate when it does the least harm or no harm to the colony whatsoever
The ideal time for treatment is when there are no honey supers in beehive yet (Spring), or after there are no honey supers anymore (Autumn). It is possible, however, to use Varroa Terminator during the entire season with small procedure adjustment.
When to do first treatment?
First and the most important period is when fruit trees bloom. The possibility of Spring treatment is an indisputable advantage of hyperthermic treatment and it has a major impact on reproductive potential of varroa mites
We could not treat for varroa mites in at least six months. It surely has been reproducing, but we are not even sure how many reproductive cycles passed. Spring treatment also provides infestation rate check in individual colonies.
At this time it may seem nothing is wrong even at different rates of infestation.
Table 1: Varroosis development amounts in a colony without Spring treatment
| Time | Initial amounts (pcs) | ||||||
|---|---|---|---|---|---|---|---|
| April 1st | 10 | 20 | 50 | 100 | 200 | 300 | 500 |
| May 1st | 20 | 40 | 100 | 200 | 400 | 600 | 1000 |
| June 1st | 40 | 80 | 200 | 400 | 800 | 1200 | 2000 |
| July 1st | 80 | 160 | 400 | 800 | 1600 | 2400 | 4000 |
| August 1st | 160 | 320 | 800 | 1600 | 3200 | 4800 | |
| September 1st | 320 | 640 | 1600 | 3200 | 6400 | ||
Table 1, first row shows initial amounts of varroa. The amount of varroa mites doubles every month and numbers in red indicate a critical level if there is no treatment.
We must not let the colony enter new season with more than 50 varroa mites. A colony without Spring treatment could contain nearly 2000 mites at the beginning of August, which is at critical level already
The time period when varroa is on brood is called reproductive stage and lasts 12 days. The time when mites ride on adult bees is called phoretic stage and lasts 3 - 12 days, in winter it lasts longer. It is known that during beekeeping season, there is a ratio of 20% mites on bees (phoretic mites) and 80% on capped brood (reproductive mites).
The first Spring treatment significantly reduces the number of varroa mites.
We obtain two crucial information after first treatment:
- number of phoretic mites fallen off bees
- daily count of dead mites found on sticky board of varroa bottom board as bees hatch
Example: Initial amount in April is approx. 100 mites (20 phoretic mites on bees and 80 reproduction mites on brood). After first treatment, there would be 20 phoretic mites and a daily count of dead mites found on sticky board of varroa bottom board would be 6-7 mites a day in next 12 days (7 x 12 = 84) as bees hatch.
If after first Spring treatment, we kill only 90% of mites on bees and brood altogether, then initial amounts at the beginning of the season in April would be:
Table 2: Varroosis development amounts after first Spring treatment
| April 1st, before treatment | 10 | 20 | 50 | 100 | 200 | 300 | 500 |
| Success rate 90% | -9 | -18 | -45 | -90 | -180 | -270 | -450 |
| After treatment | 1 | 2 | 5 | 10 | 20 | 30 | 50 |
Looking at Table 1, the difference between initial amounts at first Spring treatment and without Spring treatment is crucial for further varoosis development. Reducing the number of mites to a maximum of 50 in Spring, varroosis infestation slows down to such extent, that the colony can develop undisturbed within the next 4 months.
Just for comparison, chemical treatment tries to eliminate varroa mites at the end of the season. The use of organic acids at this time removes phoretic mites only, as there is only a small fraction of these, therefore the treatment is not very efficient. Next treatment time available using chemicals is possible by the end of next season, which is often too late. We need to keep in mind the mite population doubles every month.
Critical level
The amount of varroa mites endangering the entire colony is called critical level. This number varies at different authors, generally set at around 2000 - 3000 varroa mites per beehive. It is clear to any beekeeper it cannot be a fixed number, thus some books say it is 10% or 7% varroa mites of total number of bees.
Critical level can be detected by a simple reverse calculation. If there are 60 phoretic mites and daily count of 20 dead mites during 12 days on sticky board of varroa bottom board after treatment, then (20 x 12) + 60 wich equals 300 varroa mites as initial amount. Looking at Table 1, the initial level of 300 mites shows that it would reach critical level in 3 months already (by June 1st). The daily count of 30 dead mites found on sticky board of varroa bottom board after the first Spring treatment indicates massive varroosis infestation and it is necessary to do another treatment in two weeks.
When to do the next treatment?
With hyperthermia, deadlines pushing us into chemical treatment are history. The next treatment must be done at the end of season before winter feeding
It is imperative that winter bees hatch with as little damage by varroa as possible, hence we cannot let varroa mites reproduce excessively. Remove honey supers before winter feeding and treat with Varroa Terminator.
If curious about infestation levels, we can do our simple varroa monitoring.
Be careful, in case you ignore or not do this treatment on time, even if we later reduce the amount of varroa by any method, the damage is irreversible. This leads to surprising colony collapses after applying „late but successful“ chemical treatment.