Varroa Control: National Management Survey 2011-2012

There is little doubt that varroa mites are a big problem for many beekeepers. Simply put these parasites spread viruses and weaken colonies and are arguably the single most important contributor to colony losses over the last 20 years. So what’s a beekeeper to do? A summary of 2011 -2012 winter losses suffered by beekeepers who used or did not use common varroa control practices are reviewed in this survey analysis.

Notable finds include:

  • Beekeepers who used a known varroa control product lost 23.3% fewer colonies than those who did not use a known varroa mite control product.
  • Beekeepers who used Apiguard, Api Life VAR and Formic acid based products all experienced fewer losses than those who used another known varroa mite product or used no known varroa mite control product at all.
  • Beekeepers who used screen bottom boards for 11 months lost fewer colonies than beekeepers who used screen bottom boards for some other duration.

Varroa Control

The 2012 survey asked if beekeepers used a ‘known varroa mite control product’. ‘Known varroa mite control products’ include ApiGuard, ApiLife Var, Coumaphos (i.e. CheckMite+), Fluvalinate (i.e. Apistan), Formic Acid (i.e. Mite Away II ), Sucrocide, and
other products.

Beekeepers who reported treating with a known varroa mite control product between April 2011 and March 2012 reported 6 fewer overwintering colony deaths per 100 managed colonies than those who did not report using a known varroa mite control product. In other words, beekeepers who reported treating for varroa mites lost 23.3 % fewer colonies than those who did not report such use. Sixty-one percent of beekeepers reported that they did not use a varroa mite control product.

Know Varroa Mite Control Produce Use

varroa control use

Looking at the data by Northern and Southern region, beekeepers in northern states that treated with a known varroa mite control product reported 6.1 fewer overwintering colony deaths per 100 managed colonies than those who did not use a varroa mite control product. In other words, beekeepers in northern states who reported treating for varroa mites lost 23% fewer colonies than those who did not report such use. There was no significant difference among southern beekeepers who used or did not use a known varroa mite control product.

We do not know if the responding beekeepers applied the products according to label directions. It is likely that some of those who reported using a product did so using concentrations and delivery methods that differed from the label directions. This may affect the results reported here. More detailed questions regarding doses and application method are planned for future surveys.

Control products

THYMOL BASED PRODUCTS

apiguardapilifevar

Beekeepers who reported treating with ApiGuard reported 6.7 fewer overwintering colony deaths per 100 managed
colonies than those who did not report using a known varroa mite control product. In other words, beekeepers who reported treating with ApiGuard lost 26% fewer colonies than those who did not report treating with any known varroa mite control product.

Beekeepers who reported treating with ApiLife Var reported 7.5 fewer overwintering colony deaths per 100 managed
colonies than those who did not report using a known varroa mite control product. In other words, beekeepers who
reported treating ApiLife Var lost 29.1% fewer colonies than those who did not report treating with any known Varroa
mite control product.

COUMAPHOS AND FLUVALINATE

Beekeepers who reported treating or not treating with a Coumaphos-based product (e.g. CheckMite+), at least once (44 beekeepers managing 1,624 colonies), between April 2011 and March 2012 did not loose significantly fewer or more colonies than beekeepers who used another product (3,565 beekeepers managing 231,634 colonies) or beekeepers who used nothing (2,217 beekeepers managing 27,915 colonies).

Beekeepers who reported treating or not treating with a Fluvalinate-based product (e.g. Apistan), at least once (116 beekeepers managing 1,762 colonies), between April 2011 and March 2012 did not loose significantly fewer or more colonies than beekeepers who used another product (3,493 beekeepers managing 231,496 colonies) or beekeepers who used nothing (2,217 beekeepers managing 27,915 colonies).

FORMIC ACID BASED PRODUCTS

Beekeepers who reported treating with a formic acid based product reported 7.9 fewer overwintering colony deaths per 100 managed colonies than those who did not report using a known varroa mite control product. In other words, beekeepers who reported treating with a formic acid-based product lost 30.7% fewer colonies than those who did not report treating with any known varroa mite control product.

Table: Formic Acid Use
Total Number of  Respondents Providing  Valid Responses Total Number of Colonies Managed Average Number of Colonies Managed Average Colony Loss

Mean

Standard Error

Mean(%)

Lower 95% CI

Upper 95% CI

Formic This Product Used

666

64,973

97.6

31.1

17.9

16.1

19.6

Other Product Used

2,943

168,285

57.2

12.5

24.7

23.6

25.9

Nothing Used

2,217

27,915

12.6

2.4

25.8

24.4

27.1

OTHER PRODUCTS

Other products asked about include Sucrocide, herbal products (eg.cinnamon, garlic, wintergreen), powdered sugar, and mineral oil. Few beekeepers reported using these products and no significant differences in losses where detected. Details on the number of beekeepers using the products and analysis of losses can be found in the appendix items below.

Integrated Pest Management Techniques

DRONE BROOD REMOVAL

Varroa mites are attracted to capped drone brood more than they are worker brood. Removing frames of capped drone brood does reduce the population of varroa mites in colonies, in controlled field studies. This technique was reportedly used by 658 beekeepers who managed 40,517 colonies. When compared to 2,441 beekeepers, managing 79,905 colonies, who did not use this technique, no statistical differences in reported winter losses were detected. Beekeepers use this technique in varying degrees  (7% of beekeepers used this technique in 1-50% of their colonies, 4% used it in 51-99% of their colonies, and 11% used it in all of their colonies). No significant differences were detected between groups, but it does seem that using the technique in a higher percentage of hives helps reduce losses.

We did not collect data on how many times beekeepers removed drone combs or on how much drone comb they removed. This would have a very large impact on drone brood removal’s effectiveness as a varroa mite control technique. Also, Drone brood removal is not a stand-alone mite control technique, so multi-factorial analysis may demonstrate some benefits that are not evident here.We plan to collect this data in future years.

SCREEN BOTTOM BOARDS

Using screened bottom boards instead of solid bottom boards is understood to reduce varroa populations in colonies by allowing dislodged mites to fall through the screen instead of being able to land and climb back onto bees . This is a popular technique with 93% or 2,898 responding beekeepers using this practice in at least some of their colonies. No difference in winter losses were detected between those who used or did not use this technique when analyzing all data or when comparing regional differences. However, beekeepers who employed screen bottom boards for 11 months lost fewer colonies, on average than those who employed screen bottom boards for any other amount of time.

SMALL CELL COMB USE

Some beekeepers report the use of combs with worker cell sizes smaller than what is conventionally used reduces varroa mite populations in colonies. The beekeepers that responded they used this technique did not loose significantly fewer or more colonies over winter as beekeepers not using this technique.

DISCLAIMER

It’s important to note that this was a mono factorial analysis – so we did not look at the effects caused by using multiple products in combination had on winter survival. We hope to do this in the future as we collect additional data from many more beekeepers.

This information is for educational purposes only. References to commercial products or trade names do not imply endorsement by the Bee Informed Partnership or its members. The results presented here are the summary of the population who responded. The sample may not be representative of the beekeeping population at large. These results simply highlight differences in the sample population. The results cannot be considered conclusive, causative, protective, or attest to product efficacy or lack of efficacy.

Methods

Management Survey 2011 – 2012

How average losses were calculated and presented  |  Watch a vlog here

Appendix Items

Download the complete reports in the list below

Varroa control 

All survey reports listed here: Bee Informed National Management Survey 2011-2012 

Written By: The Bee Informed Team

has written 48 post in this blog.

The Bee Informed Partnership is a collaboration of efforts across the country from some of the leading research labs and universities in agriculture and science to better understand honey bee declines in the United States. Supported by the United States Department of Agriculture and the National Institute of Food and Agriculture, we’re working with beekeepers to better understand how we can keep healthier bees. The key to our success is the true partnership we maintain across a wide range of disciplines including traditional honey bee science, economics, statistics, and medical research that makes all these tools available to this important research. And just as important as the tools are the people. We not only have the leading researchers in the honey bee industry, we also have advisory boards from the commercial beekeeping industries, almond and other commercial growers, as well as naturalists and conservationists from across the country.