Sustainable parasitic mite control for honeybees

Final Report for LNE03-188

Project Type: Research and Education
Funds awarded in 2003: $134,710.00
Projected End Date: 12/31/2006
Matching Non-Federal Funds: $75,882.00
Region: Northeast
State: Pennsylvania
Project Leader:
Dr. Nancy Ostiguy
Pennsylvania State University
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Project Information

Summary:

Note to the reader: appendices mentioned below are available from Northeast SARE

Sideline and hobbyist beekeepers are the primary beneficiaries of this project. Secondary beneficiaries include the large migratory beekeepers and those who rely on honey bees for pollination and bee products. We targeted two changes in beekeeper behavior. The first change we wanted to achieve was to have beekeepers monitor for varroa to determine if the economic threshold had been exceeded prior to using a miticide treatment. The second change was to increase the number of beekeepers who adopted of at least two Integrated Pest Management (IPM) tactics to control varroa. To achieve the first goal we recruited beekeepers to participate in a monitoring project that would test the efficacy of the economic threshold to prevent colony loss during the winter. To achieve the second goal we recruited beekeepers to participate in scientific studies testing the efficacy of IPM control tactics. These beekeepers were then to spread the success of their experience to other beekeepers to increase the rate of adoption of IPM tactics.

The sideline and hobbyist beekeeper have begun to monitor colonies regularly. We were able to increase the size of the toolbox available to beekeepers; they have implement IPM tactics to reduce the growth of varroa populations. We have seen a shift toward lower miticides use during the life of this project. A substantial shift has occurred in the type of miticides used; more beekeepers are using non-chemical tactics and least toxic miticides rather than the more toxic miticides. Due to the increase in varroa monitoring, implementation of additional IPM tactics and the use of less toxic miticides, beekeepers will have reduced costs from unnecessary miticides use. Additionally, fewer sublethal impacts on honey bees from miticides should be observed and lower to no measurable residue of pyrethroid or organophosphate miticides should be detectable in honey and beeswax. Beekeepers are using more preventative tactics to reduce the population growth of mites and they are looking more closely at overall colony health to decrease the bee’s susceptibility to disease.

Honey bee populations are at risk of elimination because of the combined threat of varroa mites and honey bee viruses. Our recent work demonstrates the transmission of deformed wing virus (DWV) via contaminated food. We also observed a linear relationship between the prevalence of DWV and the number of times a colony replaces its queens. Currently we are experiencing a large die-off of bees (Colony Collapse Disorder). This die-off is likely a combination of parasite (varroa), disease (virus, bacteria and protozoa) and nutritional factors. Varroa vectors several honey bee viruses and we have observed in bees sampled from those colonies that have suddenly collapsed have been found to contain DWV, sacbrood virus (SBV), blackened queen cell virus (BQCV), Kashmir bee virus (KBV), chalkbrood, and American Foulbrood. It is likely that the colonies collapsed because DWV titers became too high. DWV levels probably increased tremendously because mite levels were allowed to exceed the threshold. Bee samples are currently being processed and additional samples from other beekeepers are being sent to us for analysis. The research projects conducted with beekeepers have helped us to establish additional relationships in the beekeeping community that are help us work on this emerging problem.

Introduction:

The existence of honey bees is threatened by the varroa mite and the viruses it vectors. Feral bees have almost completely been eliminated from the environment while the maintenance of managed honey bees for pollination and honey and other hive products is extremely difficult due to this pest. Most beekeepers have depended on miticides for varroa control but resistance is becoming more common. Beekeepers are also beginning to perceive adverse changes in their colonies that they attribute to the use of miticides. This project is designed to help beekeepers reduce their use of miticides. The resulting residues in wax and bee products will be reduced along with production costs, through decreased colony mortality.

In order to reduce the impact of varroa mites it is necessary for beekeepers to do three things: 1) monitor their colonies for mites, 2) implement pest management tactics to limit the growth of the mite population, and 3) implement the least toxic control tactic when mites have reached threshold. The objective of this project was to change the behavior of beekeepers. Most beekeepers did not monitor for mites. As a result of this project, monitoring of colonies has increased in the last three year. When asked, 80% of beekeepers report that they monitor their colonies for varroa. Unfortunately, the type of monitoring needs to be addressed further. Some beekeepers believe monitoring includes looking for mites on bees as the do regular colony maintenance. This is not monitoring. By the time mites are visible on bees, the number of mites in a colony exceeds the economic threshold.
The second beekeeper behavior we attempted to change was their adoption of Integrated Pest Management (IPM) tactics to control varroa. This objective has been achieved. At this time a majority of hobbyist and sideliner beekeepers have permanently installed screen bottoms on their hives. This tactic reduces the number of mites, when they drop to the bottom board, from attaching to another bee. Other less frequently used IPM tactics include removal or sealing off weak/dead colonies (0.5%), increasing the distance between colonies (0.5%), removal of most highly infested colonies from apiary (1%), selection of apiary location (5% of beekeepers), removal of sealed brood – either drone or worker (5%), resistant bee stock (20% in any one year), and splitting colony (25%).

Another goal of this project was to reduce the risk of chemical contamination of hive products along with reducing potential sublethal effects of miticides on bees. We have achieved this goal. A majority of beekeepers are replacing more toxic miticides with less toxic miticides. This accomplished two things. The risk of chemical contamination of hive products is reduced and the development of resistance by susceptible mites is less likely.

We achieved our goal of beekeeper participation in the scientific testing of IPM tactics. Between 10 and 20 beekeepers participated each year in studies. The beekeepers so liked being able to work with researchers to test tactics in real-life situations that we continue to get requests to work with beekeepers to test IPM tactics. Several experiments will be performed in this next (2007) season. One experiment was implemented in October 2006 to determine if feeding electrolytes to bees prior to the onset of winter would increase survival rates; four separate apiaries are included in this experiment. A second experiment, with 6 separate apiaries, was implemented in July 2006. Findings from these project have been or are being incorporated into the MAAREC website (http://maarec.cas.psu.edu/index.html). Additional updates will occur when the results from future beekeeper-instigated studies are known.

Performance Target:

“Two changes in beekeeper behavior are targeted: 1) 500-1000 beekeepers will be monitoring varroa levels to determine if a threshold has been exceeded prior to treating the colony with a miticide and 2) 100 beekeepers will have implement at least IPM tactics to control varroa.”
“This project targets 300 of the approximately 5000 hobbyists and 700 sideliners in MAAREC to participate in planning workshops. From the 300 beekeepers, 10 beekeepers will participate in the evaluation of IPM tactics plus mite monitoring. Each of the beekeepers will hold, with our assistance, a workshop at his/her apiary to demonstrate IPM tactics and monitoring. Fifty beekeepers will attend each apiary workshops (400-500 total) and 40-80 will implement multiple IPM tactics to control varroa during the second year. Few beekeepers currently monitor for varroa and IPM cannot be implemented effectively without monitoring; we will encourage beekeepers to begin monitoring for varroa. Approximately 200 beekeepers each year will be recruited to begin monitoring.”

Target One: “500-1000 beekeepers will be monitoring varroa levels to determine if a threshold has been exceeded prior to treating the colony with a miticide.”
Each year surveys were distributed via the U.S. mail using State Beekeeper Association mailing lists or through the State Apiary Inspection Program. Additionally, surveys were distributed at beekeeper meetings. Notices were placed in various beekeeper newsletter to encourage beekeepers to complete yearly surveys using either the hard copies that were distributed or electronic copy on the MAAREC web site. Unfortunately, the response rate was extremely poor throughout the study period. To supplement the information we were able to glean from the surveys that were returned, information was obtained from the apiary inspection program in Pennsylvania (where the return rate was the lowest). Information was also obtained by directly questioning beekeepers attending workshops and meetings. All information we have to evaluate whether or not we achieved our objectives is anecdotal and not necessarily reliable.
The apiary inspectors during the three years of the project were instructed to demonstrate mite monitoring techniques. In the group of beekeepers who were inspected a second time during the project’s duration (inspections are biannual) inspectors found that greater than 50% of beekeepers report that they check the mite levels in their colonies at least once per year, usually in August or September. At least 25% are monitoring for mites more than once.
Initially our recruitment efforts to get beekeepers to monitor for mites were disappointing. We discovered that we could increase the participation rate by requesting that the beekeepers send the results of the monitoring to us for inclusion in an evaluating of the efficacy of the suggested mite threshold. As a result we were able to obtain the participation of over 100 beekeepers each year, thus attaining our target. The data collected from the beekeepers has been of limited use because of the lack of consistency in the data. Some beekeepers reported mite number but not colony survivorship information or the linkage between the mite numbers in a colony and colony survivorship was questionable.
We achieved our goal for this target. The beekeeper who responded to the surveys indicate that more than 80% of beekeepers are monitoring their colonies for varroa mites. Even if it is assumed that the survey over-states monitoring behavior, we met our goal of 500-1000 monitoring for varroa mites. If only 25% of beekeepers are monitoring for mites in the MAAREC region over 1,400 beekeepers are tracking mite levels in their colonies.
Target Two: “100 beekeepers will have implemented at least two IPM tactics to control varroa.”
For the same reason described above, the information we have concerning whether or not we achieve our goal of 100 beekeepers implementing at least two IPM tactics to control varroa is anecdotal.
At this time over 50% of beekeepers have implemented at least one IPM control tactic. The most common method has been screened bottoms. There is a substantial amount of misinformation about how to properly use screened hive bottoms but we are working to correct this problem. A number of the beekeeping suppliers sell screen inserts rather than screened hive bottoms. Inserts increase the frequency of wax moth infestation and the at least some of the mites that fall below the screen insert onto the bottom board are able to find another host. The screened hive bottoms do not create an environment conducive for the reproduction of wax moth. Additionally, the mites drop out of the hive and cannot crawl back onto a bee.
Other less frequently used IPM tactics include removal or sealing off weak/dead colonies (0.5%), increasing the distance between colonies (0.5%), removal of most highly infested colonies from apiary (1%), selection of apiary location (5% of beekeepers), removal of sealed brood – either drone or worker (5%), resistant bee stock (20% in any one year), and splitting colony (25%). Based upon the responses we received from the surveys, workshops and apiary inspections, between 15% (855) and 25% (1400) of beekeepers have implemented two or more IPM varroa control tactics. We exceeded our second target.
While there seems to be an understanding among workshop participants of the efficacy of the removal of weak or dead colonies to prevent robbing (and the spread of mites), few beekeepers are implementing this tactic. Colony removal is implemented less frequently than sealing off a colony because removal is extremely time intensive and a major change in colony management. Either tactic requires a beekeeper to visit his/her apiary more frequently than is typical. We are continuing to work with beekeepers to improve the practicality of this tactic and will continue to emphasis this tactic in future workshops because this tactic not only would reduce the spread of mites through an apiary it also would reduce the spread of other diseases. If our estimate of the adoption rate of this tactic is correct, approximately 25 beekeepers are visiting their apiaries frequently enough to make the removal or the sealing off of a hive an efficacious method to reduce the spread of mites.
A few beekeepers have increased the distance between colonies to reduce the impact of drifting. When beekeepers learned that placing colonies in a long line would increase drift, they slowly altered the layout of their apiaries. Once research is completed this year (summer 2007) on the impact of spacing on bee drift, we expect to see beekeepers implement this tactic more frequently. Once 5% of more beekeepers implement this tactic we expect there will be a substantial jump in adoption rate because there are several advantages to the beekeeper of increasing spacing. The most obvious one is the ability of one colony to influence the behavior of another colony is reduced. Others include decreased robbing and more room to maneuver while working colonies. This tactic has several limitations including 1) larger operations will have greater difficulty increasing colony spacing; 2) additional apiaries may be needed to accommodate the colonies that had been in a single apiary; and 3) the cost of a bear fence may be higher if a larger area needs to be enclosed. Assuming our estimate of the adoption rate of this tactic is accurate, approximately 25 beekeepers are increasing the spacing between their colonies to reduce mite populations.
While a number of beekeepers have seen the impact that apiary location can have on mite population size this is a difficult tactic to implement. Many beekeepers in the MAAREC region have lost apiaries in recent years because some property owners are no longer willing to allow bees to be housed on their property. As the availability of apiary locations is reduced, even more ideal apiary locations are lost. Assuming our estimate of the adoption rate of this tactic is accurate, approximately 25 beekeepers in the MAAREC region are selecting apiary locations that reduce mite populations.
Sealed brood removal is considered to be too time intensive by most beekeepers. While this tactic is used extensively by European beekeepers with small operations, American beekeepers find this method to be contrary to most common colony management regimes. We have been working with a few beekeepers to reduce the work involved and to devise a routine for the insertion of drone comb (the most efficacious tactic) and subsequent removal, freezing and reinsertion. Even though this tactic is not looked upon favorable by many beekeepers, approximately 280 beekeepers in the MAAREC region are using this method. These beekeepers tend to be individuals who are the most reluctant to use miticides and tend to have between 1 and 25 colonies.
A number of purportedly resistant stocks are available for beekeeper purchase. Unfortunately there is tremendous variability in the efficacy of the stock with the same stock, e.g., Russian, being reported as effective in one year but not effective in another year. It is unclear how much this variability is due to the stock itself rather than differences between beekeeper operations. In any particular year there are approximately 1,110 beekeepers in the MAAREC region who will have purchased resistant queens. A beekeeper who purchased resistant stock but did not see an improvement in colony survivorship will not necessarily purchase resistant stock again even though the reason for the failure of colonies to over winter may be due to a variable other than the size of mite population.
Beekeepers commonly split strong colonies to increase the total number of colonies. Some beekeepers have found this to be an effective way to reduce mite populations. Beekeepers are reporting to each other that colonies split either at the end of their first year of existence or early in their second year are more likely to survive beyond the normal 2 year life expectancy of colony not treated with a miticides. Because “making splits” is a common management technique, this mite reduction tactic is becoming popular. If the estimated adoption rate of this tactic is accurate, approximately 1,400 beekeepers in the MAAREC region are selecting apiary locations that reduce mite populations.
Target Three: Three hundred of the approximately 5000 hobbyists and 700 sideliners in MAAREC were expected to participate in planning workshops and10 beekeepers will participate in the evaluation of IPM tactics plus mite monitoring.
We fell short of the project target of 300 beekeepers attending planning workshops. It was nearly impossible to get beekeepers to come to these meetings. Rather than forgo the participating of beekeepers in the planning of the kinds of IPM tactics that would be available or limit the recruitment of beekeepers to participate in the monitoring program, we attended every beekeeper meeting we could during the first year and a half of this project. At each meeting beekeepers were recruited to undertake a study of any IPM tactic they thought worthwhile and/or to participate in colony monitoring.
Target Four: Ten beekeepers were to be recruited each year to participate in the testing of IPM tactics. And, the ten beekeepers were to hold a workshop at his/her apiary to demonstrate IPM tactics and monitoring. Fifty beekeepers were expected attend each apiary workshops.
We met or exceeded our goal to recruit beekeepers to participating in the scientific testing of IPM tactics to control varroa. Each year between 10 and 20 beekeepers agreed to undertake studies. Each participating beekeeper indicated that they found the experience worthwhile, even if they stopped participating midway through the summer. The results of a one study were of sufficiently high quality that the data have been prepared for publication. The manuscript is written and is being reviewed by each of the participating beekeepers prior to submission.
We did not meet our goal of 50 beekeepers attending workshops at the apiaries of beekeepers who participating in the testing of IPM tactics. Scheduling these workshops with the beekeepers was extremely difficult, participating beekeepers lack interest in holding the workshops and attendance at the workshops was virtually non-existent. Instead of trying to force the workshop model on reluctant individuals, we, along with the participating beekeepers, presented results at many meetings. The presentations by the beekeepers were especially well received.
Target Five: “40-80 (workshop participants) are expected to implement multiple IPM tactics.”
We achieved this goal even though we were unable to hold workshops at beekeeper apiaries. See Target Two.
Target Six: “Approximately 200 beekeepers each year were expected to begin monitoring each year.”
We achieved this goal. Each year between 25 and 50 beekeepers volunteered to monitor for mites and send their data to Penn State for verification of threshold efficacy. Based upon survey results and other sources (See Target One) more than 200 beekeepers (4% of the hobbyist and sideline beekeepers in the MAAREC region) each year began monitoring for varroa mites.

Cooperators

Click linked name(s) to expand
  • Dewey Caron

Research

Materials and methods:

Because one goal of this project was to engage beekeepers in research testing IPM tactics to control varroa mite populations, a number of different studies were designed. Appendix 10 contains several examples of how the studies were conducted and the type of data collected. Recruiting beekeepers to conduct scientific studies was not difficult. It was difficult to get the beekeepers to actually implement a study and to complete the data collection for a full season was much more challenging. Most of the beekeepers were very interested in conducting the research and more than half were able to complete projects each season. Some beekeepers felt we should be doing the work on the colonies from their apiaries that were a part of the study since we were being paid to conduct the research and they were not.

The remainder of the project was to increase the number of beekeepers monitoring for varroa and the number of beekeepers using IPM tactics to control varroa populations. Participation rates in the varroa monitoring portion of the project were increased by requesting that the beekeepers send the results of the monitoring to us for inclusion in an evaluating of the efficacy of the suggested mite threshold. The data collected from the beekeepers has been of limited use because of the lack of consistency in the data. Some beekeepers reported mite number but not colony survivorship information or the linkage between the mite numbers in a colony and colony survivorship was questionable. We had not included the evaluation of the efficacy of the economic threshold as part of the project. Therefore we will attempt to evaluate the economic threshold in the future.

Research results and discussion:

“Research Component

1. Obtain baseline data (2000 beekeepers). Organize meetings (300 attendees). Recruit beekeepers (200 – monitoring; 10 – IPM tactics).

2. Year 1: implement IPM tactics (10 beekeepers); all beekeepers complete study. Year 2: 40-80 beekeepers recruited and implement IPM tactics; 70% complete year 2.

3. Implement monitoring (200 beekeepers, year 1); 50% percent will remain in the study. 200 beekeepers will be recruited for the 2nd year; 75% will complete the study.

4. Collect and analyze data.

Outreach and Education Component

5. Provide two two-hour apiary visits on IPM tactics, monitoring, and colony health.

6. Conduct apiary workshops with beekeepers on IPM varroa control tactics.

7. Conduct year-end workshops. Provide update on project goals and the best practices found.

8. Both years, conduct survey on implementation of IPM control and to determine monitoring.”

Milestone One: We were unsuccessful at obtaining baseline data on 2000 beekeepers. The response rates of our surveys were extremely poor and we were never able to alter this. Planning meetings were unsuccessful. By resorting to attending meetings that beekeepers were already at, we were able to recruit beekeepers to monitor for varroa mites and beekeepers to implement IPM tactics.
Milestone Two: We were able to recruit 10 beekeepers to conduct studies during the first year of the study. We were unable to increase the number of participating beekeepers in subsequent years but we did maintain between 10 and 15 participants each year. We continue to work with beekeepers interested in conducting research.
Milestone Three: It was difficult to find 200 beekeepers willing to participate formally in monitoring. We found that a more effective means to communicate the need to monitor was by asking the apiary inspectors to demonstrate at least monitoring method while inspecting colonies. Beekeepers were able to see that looking at bees while doing standard colony maintenance was insufficient for determining if the economic threshold had been reached. We were able to increase the rate of monitoring for mites significantly as a result.

Milestone Four: Data from most of the studies conducted by beekeepers lacked the necessary rigor to allow for data analysis. One study that evaluated the efficacy of 4 ‘soft’ miticides was completed in such a way that an article has been written and the participating beekeepers are currently reviewing the completed manuscript. The article will be submitted to the American Bee Journal.

Milestone Five: With the exception of the study where three beekeepers cooperated on their research we were unable to coordinate multiple visits to apiaries with the beekeepers. The beekeepers found it very difficult to meet more than a single time. Because they were voluntary participants, we did not feel that we could insist on apiary visits.

Milestones Six and Seven: We failed to accomplish either of these milestones. Workshops at the beekeeper apiaries did not turn out to be practical. Scheduling the workshop was nearly an insurmountable challenge and then obtaining beekeeper participation at these workshops was even more difficult. As a result we brought our results and experiences to meetings that beekeepers were already attending. At two regional meetings (Eastern Apiculture Society and the Heartland Apiculture Society), we did demonstrations of monitoring tactics and hands on workshops on IPM tactics and scientific study methods.

Milestone Eight: The response rate, as described in Milestone One, was abysmal. We were required to rely on information obtained from apiary inspectors and personal interactions with beekeepers at various meetings. When beekeepers were asked about why they did not respond to the surveys they indicated that they did not understand why we needed to ask the same questions every year. While we were able to explain to each individual the need for continuous data collection, if this is the attitude of most beekeepers it is not surprising that the response rate was so low.

Participation Summary

Education

Educational approach:

The following slide shows or fact sheets available on the MAAREC web site (http://maarec.cas.psu.edu) were updated using the results of work from this project.

1) Powdered Sugar Sampling to monitor Varroa mite population in Honey Bee colonies
2) Economic Thresholds & IPM Strategy
3) Integrated Pest Management (IPM) Strategies for Parasitic Bee Mites
4) Honey Bee Parasites, Pests and Predator
5) Bee Diseases, Pests and Parasites (Honey Bee Maladies)

The impact of the MAAREC web site is substantial. The MAAREC web site has over 3,500 hits per day. The average number of page views per day exceeds 1,500. The average number of visits per day exceeds 650 and the majority (76%) of the visits are from the United States. During one one-month period (January 2006) there were over 9,500 unique visitors.

The following outreach activities and education efforts were undertaking.

1) Great Insect Fair (2005, 2006): Public outreach concerning honey bees and their pests, parasites and diseases. Honey tasting was featured.
2) Pennsylvania State Beekeeper Annual Meeting (October 2005, 2006): Research projects by beekeepers were presented
3) West Virginia State Beekeeper Spring Meeting (2005): Research projects by beekeepers were presented
4) Heartland Apiculture Society Meeting (Summer 2005): Research projects by beekeepers were presented, workshop for beekeepers on how to conduct experiments, demonstration of monitoring techniques
5) Eastern Apiculture Society Meeting (Summer 2004): Research projects by beekeepers were presented, workshop for beekeepers on how to conduct experiments, demonstration of monitoring techniques

No numerical assessments of the effectiveness of these activities exist. Comments by participants were favorable. Attendance at meetings and workshops varied between 25 and 200. Insect Fair attendance each year is approximately 5,000-6,000 individuals.

The following publications have resulted from this project.

1) Shen M, Cui L, Ostiguy N, & Cox-Foster DL. 2005. Intricate transmission routes and interactions between picorna-like viruses (Kashmir bee virus and sacbrood virus (SBV) with the honey bee host and the parasitic varroa mite. J. of General Virology 86:85-93.
2) Ostiguy N, Cox-Foster D, Yang X, Caron D. & Embrey M. 2005. Bees, Mites and Viruses (Abstract). American Bee Journal 145:432.
3) Kevan PG, Hannan MA, Ostiguy N, & Guzman-Novoa E. 2006. A Summary of the Varroa-Virus Disease Complex in Honey Bees. American Bee Journal 8:694-697.
4) Ostiguy N, Cox-Foster D, Kalkstein A, Thompson O, Williams M. 2007. The Continuing Story of Honey Bee Viruses. (Abstract). American Bee Journal (in press).

The efficacy of these publications is difficult to judge. Beekeepers are more apt to read the last three publications but an occasional beekeeper will mention having read an article from the peer-reviewed literature.

Additional Project Outcomes

Project outcomes:

Impacts of Results/Outcomes

Impact on Beekeepers

According to our survey results, 80% of beekeepers are monitoring their colonies for varroa mites. Even if it is assumed that the survey over-states monitoring behavior, we met our goal of 500-1000 monitoring for varroa mites. If only 25% of beekeepers are monitoring for mites in the MAAREC region over 1,400 beekeepers are tracking mite levels in their colonies. The impact of this change on beekeeping should be substantial as beekeepers have been treating their colonies on a pre-determined schedule. The quantity of miticides placed in colonies should be reduced as a result. Therefore, the non-target adverse impact of miticides exposure on honey bees should be reduced, along with the potential for hive product contamination. The risk of development of resistance to the remaining effective miticides will be reduced.
Over 50% of beekeepers report that they have implemented at least one IPM control tactic – the inclusion of screened hive bottoms in their hive equipment. This single tactic, while it has been shown my many researchers (and in our beekeeper evaluations) to reduce mite levels in a colony, is not sufficient to keep mite levels below the economic threshold. We were interested in increasing the number of beekeepers who implemented at least to IPM varroa control techniques. If it was assumed that no beekeeper has implemented more than one control tactics and we summed the use rates for all tactics, then 102% of beekeepers are using IPM tactics to prevent or to slow the growth of mite populations. This would be an unreasonable estimate because 1) some beekeepers have implemented more than two tactics and 2) some beekeepers have implement one of these less frequently used tactics instead of screened hive bottoms. Based upon the responses we received from the surveys, workshops and apiary inspections, it would be reasonable to estimate that between 15% (855) and 25% (1400) of beekeepers have implemented two or more IPM varroa control tactics. Therefore, we exceeded our second target.

Impact on other agricultural or non-agricultural audiences

The impact of this project of other agricultural and non-agricultural audiences will be indirect. If we assume that monitoring for a pest and preventing or slowing the growth of a pest population improves the health of the target species, this project will positively impact the health of honey bees. Because of the severe impact of varroa mites on honey bee health, we are not at a point where we can say that the results of this project will increase the reliability of pollination services provided by honey bees. To achieve greater reliability of pollination services, more work will need to be done to control the growth of varroa populations and to reduces its potential to vector viruses and other pathogens.

Economic Analysis

No formal economic analyses were performed as part of this study. It is clear that negative repercussions would result if honey bees were not available for pollination. While this drastic of a situation was not envisioned at the beginning of the project, the Colony Collapse Disorder that appear in October 2006 could result in serious problems for farmers who rely on honey bees to pollinate their crops. Many of the migratory beekeepers have lost between 70% and 100% of their colonies. If these losses cannot be made up by colony splits, packages and nucs in spring 2007, there could be a lack of pollinators for the 2007 crops. Describe the economic repercussions of your project on farm viability.

Colony Collapse Disorder (CCD) has put a severe strain on the economic viability of many migratory beekeeper operations. It is expected that some of these beekeepers are no longer in business. The impact of the information from this project was never expected to apply to migratory beekeepers. Assuming that CCD does not severely impact sideline or hobbyist beekeepers, the monitoring and IPM tactics that were the core of this project are not likely to result in a greater profitability for those beekeepers who stay in business. Monitoring increases the amount of time necessary for beekeeping. Most of the mite control IPM tactics that are favored by beekeepers have low up-front costs and require little additional time for implementation. The cost of implementing IPM tactics may be less than the costs associated with the application of miticides if the number of colonies and or queens lost decreases. [It is unknown at this time if replacement of miticides with IPM tactics will be as, more or less effective at reducing overall colony loss due to mite infestations.]

Farmer Adoption

It is unclear if any improvement in the profitability will result from this project. The current situation with the Colony Collapse Disorder (DDC) has resulted in the questioning of all our tactics to improve honey bee health. Until more information is known about CCD we will not know if the monitoring for varroa mites and treating once the mites reach threshold results in any improvement in the profitability of beekeeping. This also means that the IPM tactics to control varroa mites that were tests by beekeepers as a part of this project may or may not contribute to the profitability of beekeeping.

This project has improved environmental stewardship because more beekeepers 1,400 beekeepers are monitoring for mites rather than using a miticide on a predetermined schedule. Additionally, beekeepers are incorporating IPM tactics to slow the growth of mite populations. These tactics increase the length of time before mite levels exceed the economic threshold. Approximately 50% (2,500) beekeepers have implemented at least one IPM tactic – screened hive bottoms. If it is assumed that the majority of beekeepers who have implemented a mite control tactic other than screened hive bottom have also installed screed hive bottoms, then approximately 2,000 beekeepers are using more than one IPM tactic for mite control.

Assessment of Project Approach and Areas of Further Study:

Areas needing additional study

More research is needed in a number areas, including monitoring methods for viruses and other disease, determination of economic thresholds when other diseases and pests are present, differences in economic thresholds between migratory and non-migratory operations, understanding the interaction between honey bee nutrition and mite impact, determination of the efficacy of mite interventions at different times of the year, determination of any differences on colony survivorship if summer versus winter bees are parasitized by mites, and determine the impact of mites on foraging success. Some of these questions can be answer by researchers cooperating with beekeepers to conduct studies. Other information, once understood at the research level would need to be translated into beekeeping practices and tested within beekeeping operations.

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.