Bee loss update

The first posting on WVBA winter losses reported loss of 122 colonies = 46 % average loss, slightly lower than the statewide loss of 48%, which equals the highest for OR backyarders. The 46%loss was the highest WVBA level of the previous 4 years and 9.5% above the 4 year average.  The trend is sloped upward, indicating losses have been increasingly larger for WVBA members.

Typical of the statewide data, the WVBA respondents are largely new beekeepers. 54% of WVBA respondents had 1, 2 or 3 fall colonies, 7 (20%) had 4-6 colonies, 5 had 7 or 8 colonies (14%) and 2 had 10 and another 2 had 12 fall colonies, the largest number of WVBA respondents. Nineteen individuals (51%) had 1, 2 or 3 years of experience (3 years experience was most common), 12 individuals had 4 or 5 years (32%), 2 each had 7 or 8 colonies  one had 10 years, another 25 and one 30, the greatest experience.

Not everyone had loss. Eight WVBA individuals (21.5%) reported total winter survival while one more, 9 individuals (24%), lost 100% of their colonies. Six individuals lost 1 colony, 10 members lost 2 colonies, 6 lost 3 colonies. And 3 lost 4 colonies.  One individual each lost 6, 7, 8, 9 and 10 colonies. Heaviest loss was 13 colonies. Varroa mites (14) and weak in fall (15) were most common reasons listed for reason for loss, followed by poor wintering and queen failure. Seven said don’t know.

A full report of the 22 WVBA respondents to the pnwhoneybeesurvey is now posted online www.pnwhoneybeesurvey. Click on top bar for 2018-19 survey results,  slide to right to access the WVBA report. Managements by WVBA members are assessed for loss level. The 26 members feeding Pollen patties  (2 each also fed pollen in frame and dry pollen) had better survival (41%) than overall for WVBA respondents (46%). Likewise the 24 individuals feeding non-liquid sugar had improved survival (41%) versus overall for WVBA members with fondant (29%) and 11 hard candy feeding showing the best survival level (38%). Two individuals who fed liquid honey had no loss.

The winterizing selections of WVBA members showed only marginal differences in survivorship. Vivaldi board use difference was 3 percentage points lower loss. The three WVBA individuals who equalized hive strength had the best survival (33% loss); those using top insulation (39% loss) also had better survival. Wind/weather break, wrapping and use of top insulation had only marginal better survivorship. The two sanitation choices that slightly improved survival was clean hive tool and generally avoid moving frames

Among WVBA members, 76% used SBB on all colonies (50% loss) while the 3 individuals (8%) who did not use them had an 86% loss. Statewide over last 5 years SBB use has resulted in essentially no advantage. However those individuals using a SBB who close them (partially  or completely) had  a 9 percentage point difference in survival.

Monitoring for mites makes a difference. Twenty five WVBA individuals (66%) monitored all colonies; they had 50% loss. Eight individuals (27%) did no monitoring and they had a 64% loss. Use of alcohol wash was much more common (43% of WVBA individuals) compared to statewide utilization (28% of individual respondents).

Three of the non-chemical alternatives have demonstrated reduced losses over past 4 year. Reducing drifting such as spreading colonies, different colony colors in apiary has demonstrated a 13% better survival, Brood cycle interruption an 11% better survival and drone brood removal a minor 2% advantage; this past year for the 5 WVBA individuals using drone brood removal losses were only 22%; 3 other managements had about a 6 percentage point advantage.

Consistently the last 3-4 years five different mite treatment chemicals have helped beekeepers statewide realize better survival.  The essential oils Apiguard and ApiLifeVar have consistently demonstrated the lowest loss level. Apiguard has a 31% better survival and ApiLifeVar has a 30% better survival record over past 4 years; both performed well for WVBA members with 10 (Apiguard) and 8 (ApiLifeVar) percentage point improved survival    Apivar, the synthetic amitraz, has demonstrated a 29% better survival over past 4 years (2016-19); for the 4 WVBA Apivar users it did not do quite that well (50% loss compared to overall 46%).

Oxalic acid vaporization over past 3 years statewide has a 13% better demonstrated better survival. Fifteen WVBA members using it had a 50% loss level. For the 16 Formic acid (MAQS) users survival was 6 percentage points greater. This product has changed and how we use it is changing so this information is more difficult to tease out of the data. This past season for example Formic Pro seemed to perform better statewide than the traditional formic MAQs pads but the one individual of WVBA lost 50% of colonies when used. One individual used formic acid in a “shop towel” delivery but lost both of his/her colonies.

Thanks to all LBBA members who supplied information. See the pnwhoneybesurvey website for more details.