This was the 18th monitoring that SGGW scientists conducted in cooperation with the non-profit organization Collos. The survey among beekeepers lasted from March 21 to May 31 of this year. Over 400 beekeepers took part in it, reporting a total of almost 18.5 thousand bee families.
How many bee colonies did we lose last winter?
According to the monitoring results, the overall level of bee colony losses in the 2023/2024 wintering period was 10.4%. This was therefore the highest result since the 2020/2021 wintering period, but it was still on the border of the acceptable level of losses (which is estimated at 10%).
Source: SGGW
The percentage of losses, however, varied greatly depending on the region of the country. In Podlasie, beekeepers lost every fourth family, and in the Opole region, every fifth. On the other hand, in Wielkopolska and the Lubuskie province, this percentage fluctuated around the 5 percent mark.
Source: SGGW
Causes of bee colony losses
The most important cause of bee colony losses was considered by respondents to be colony death (6.1% of total losses). The main cause of colony collapses was considered by beekeepers to be the colony depopulation syndrome (CDC), which is responsible for 3% of total losses. This syndrome is a consequence of the presence of a large population of the Varroa Destructor mite in colonies, as well as the diseases that accompany it. 1.3% of beekeepers considered starvation to be the cause of colony death.
Source: SGGW
The second most common cause of deaths was the loss of a queen bee or her insufficient productivity. Such bees survived the winter but were unable to develop in the spring. Such problems accounted for 3.8% of losses.
Source: SGGW
A trace percentage of losses were natural disasters, such as fires, floods or wild animal attacks. Such phenomena resulted in the loss of 0.5% of reported families.
Source: SGGW
High percentage of weak families
According to SGGW experts, it is worrying that over 10% of the reported colonies were assessed by beekeepers as being in poor condition:
Bees that survived the winter despite no problems with their queens were weak and did not develop properly. Such colonies require additional care, which is associated with costs and work. Most often, they do not develop quickly enough to collect spring honey (e.g. rapeseed or orchard honey). On a national scale, this entails high economic losses – we read in the analysis of SGGW experts.
How do beekeepers monitor and control varroa?
According to the study, 89% of the surveyed beekeepers declared that they monitor the level of varroa infestation in bee families. The vast majority, however, limited themselves to observing daily deaths and observing bees.
Source: SGGW
98.6% of respondents declared that they were fighting varroa. The dominant agent used to fight the parasite is amitraz, applied through fumigation or applied through strips. A biotechnical method is also often used – cutting out drone brood.
Source: SGGW
We would like to thank the team of the Laboratory of Insect Diseases at the Warsaw University of Life Sciences (SGGW) for providing the full results of the study.
