Fig. 1.
Fig. 2.
Fig. 3.
Fig. 4.
Distribution of healthy colonies and those infected with Vairimorpha spp_ from each experimental group
| Groups* | Years of research | Number of healthy colonies (0), and infected with Vairimorpha spp. spores expressed in a scale of (1–3) | ||||
|---|---|---|---|---|---|---|
| N | 0 | 1 | 2 | 3 | ||
| SCS | 2010 | 89 | 28 | 2 | 1 | 8 |
| MCS | 27 | 5 | 4 | 14 | ||
| SCS | 2011 | 68 | 18 | 1 | 3 | 10 |
| MCS | 23 | 6 | 1 | 6 | ||
| SCS | 2012 | 25 | 1 | 1 | 2 | 7 |
| MCS | 4 | 2 | 1 | 7 | ||
| Total | 182 | 101 | 17 | 12 | 52 | |
Distribution of viruses in bee samples taken in autumn from colonies in each experimental group in 2010 and 2011
| Groups * | Years of research | Number of healthy colonies (0), and infected by viruses | ||||
|---|---|---|---|---|---|---|
| N | 0 | ABPV | DWV | ABPV + DWV | ||
| SCS | 2010 | 71 | 21 | 9 | 2 | 0 |
| MCS | 24 | 14 | 1 | 0 | ||
| SCS | 2011 | 45 | 13 | 1 | 5 | 1 |
| MCS | 19 | 0 | 7 | 0 | ||
| Total | 116 | 77 | 24 | 15 | 1 | |
Number of dead bees with winter debris and nest adjustment in spring 2010 and 2011 in bee colonies according to Varroa infestation level expressed on a scale of 1–3
| Varroa infestation (1–3) | N | Mean number of dead bees with winter debris* | Change in the size of the nest in the spring (%) | ||
|---|---|---|---|---|---|
| Mean** | Median | Range | |||
| 1 | 23 | 1359 a | −14.2 a | −7.1 | −50 – 0 |
| 2 | 33 | 1188 a | −11.0 a | 0 | −40 – 0 |
| 3 | 38 | 1356 a | −11.4 a | −14.3 | −50 – 33 |
| Total | 95 | 1288 | −11.8 | −14.2 | −50 – 33 |
The number of Varroa mites found on the bottom boards after late summer-autumn treatments in each experimental group in 2010 and 2011_ The SCS group was divided according to the origin of the paternal colonies
| Groups* | Number of Varroa mites | ||||
|---|---|---|---|---|---|
| N | Min | Max | Mean** | SD | |
| SCS-M | 23 | 27 | 1806 | 337 a | 388.5 |
| SCS-N | 12 | 16 | 941 | 378 a | 289.4 |
| SCS-G | 19 | 43 | 922 | 354 a | 240.4 |
| MCS | 68 | 17 | 1975 | 456 a | 364.6 |
Distribution of healthy colonies from each experimental group and those infected with Vairimorpha spp_
| Healthy colonies (0), infected expressed in a scale of (1–3) | Indicators overwintering of healthy colonies and infected by Vairimorpha spp. spores | |||
|---|---|---|---|---|
| N | Mean number of dead bees in winter debris* | Change in the size of the nest in the spring (%) | ||
| Mean** | Median | |||
| 0 | 101 | 1188 a | −9.7 a | 0.0 |
| 1 | 17 | 1161 a | −12.5 a | −15.4 |
| 2 | 12 | 1208 a | −16.6 a | −16.6 |
| 3 | 52 | 1140 a | −14.1 a | −16.6 |
| Total | 182 | 1174 | −11.6 | −14.2 |
Number of Varroa mites found on the bottom boards after late summer-autumn treatments in each experimental group in 2010 and 2011
| Groups* | Apiary | Years of research | Number of Varroa mites | ||||
|---|---|---|---|---|---|---|---|
| N | Min | Max | Mean** | SD | |||
| SCS | Both apiaries | Years together | 54 | 16 | 1806 | 352 a | 316.1 |
| MCS | 68 | 17 | 1975 | 456 b | 364.6 | ||
| Both groups | Apiary (W) | Years together | 70 | 16 | 1975 | 372 a | 346.4 |
| Apiary (S) | 52 | 121 | 1806 | 412 b | 343.3 | ||
| Both groups | Both apiaries | 2010 | 72 | 16 | 1806 | 455 b | 335.5 |
| 2011 | 50 | 27 | 1975 | 345 a | 355.2 | ||
| Total | 16 | 1975 | 410 | 346.4 | |||
Number of Varroa mites before winter and some indicators of overwintering of healthy colonies and those infected by viruses
| Viral presence | N | Number of Varroa mites before winter* | Mean number of dead bees in winter debris* | Change in the size of the nest in the spring (%) | |
|---|---|---|---|---|---|
| Mean** | Median | ||||
| Healthy | 75 | 420 a | 1251 a | −11.2 a | −14.0 |
| ABPV | 23 | 485 a | 1035 a | −7.7 a | 0.0 |
| DWV | 13 | 417 a | 2047 b | −31.1 b | −33.3 |
| ABPV + DWV*** | 1 | 321 | 2621 | −16.6 | −16.6 |
| Total | 112 | 432 | 1288 | −12.7 | −14.2 |