Investigate best practice integrated Varroa mite control for the future benefit of. Australian beekeepers and farmers

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1 THE WINSTON CHURCHILL MEMORIAL TRUST OF AUSTRALIA Report by Daniel Martin 2010 Churchill Fellow Investigate best practice integrated Varroa mite control for the future benefit of I understand that the Churchill Trust may publish the Report, either in hard copy or on the internet or both, and consent to such publication. I indemnify the Churchill Trust against any loss, costs or damage it may suffer arising out of any claim or proceedings made against the Trust in respect of or arising out of the publication of any Report submitted to the Trust and which the Trust places on a website for access over the internet. I also warrant that my Final Report is original and does not infringe the copyright of any person, or contain anything which is, or the incorporation of which into the Final Report is, actionable for defamation, a beach of any privacy law or obligation, breach of confidence, contempt of court, passing off or contravention of any other private right or of any law. Signed: Daniel Martin Dated: 14 September

2 TABLE OF CONTENTS 1. Introduction Acknowledgements Glossary Executive summary Highlights Key findings Dissemination and implementation Programme 6 4. Investigate best practice integrated Varroa mite control (IVC) for the future benefit of Australia s honey bee dependent pollination industry Australia s vulnerable honey bee industry The face of future beekeeping in Australia with varroa The case for IVC learning and development IVC objectives Key IVC objectives Key IVC tools and strategies: (a) Know your foe (i.e. varroa) (b) Colony/apiary mite monitoring (c) Constructing your mite monitoring shaker (d) Mite monitoring procedure using the alcohol wash method (e) Interpreting monitoring results for determining colony/apiary mite infestation levels (f) Treatment applications (g) Selective honey bee breeding for (varroa) hygienic behaviour (h) Testing for hygienic behaviour (i) Improved beekeeper colony/apiary husbandry/management practices Conclusions Recommendations Bibliography 63 2

3 1. INTRODUCTION Australia remains the only country to be free of the economically devastating honey bee (Apis mellifera) parasitic mite, varroa (Varroa destructor) (Goodman et al. 2010). International experience has demonstrated that, as a consequence of varroa becoming established in a country (in both feral/wild and managed honey bee colonies), beekeepers (hobbyists, part-time commercial and full-time commercial) experience inevitable and significant upheaval from honey bee colony losses. Feral/wild honey bee colonies disappear. Honey bee dependant horticultural and agricultural industries become firmly reliant on managed honey bees for pollination services. The future resilience of the Australian honey bee industry will be reflected in the ability of government and the honey bee industry to be prepared in advance with the knowledge and skills necessary for effective and responsible management of varroa. This project investigates best practice integrated varroa control (IVC), as practiced in the USA, for the future benefit of. 1.1 Acknowledgements It goes without saying that I m eternally appreciative to the Winston Churchill Memorial Trust for supporting this project. I recall a previous Churchill Fellow as saying the learning experiences gained and opportunities presented from your fellowship will change your life. This has certainly been true! I m indebted to the generosity of the Churchill Trust, and I will be reminded of this generosity as I (and other Fellows) move forward and practice the invaluable learning experiences gained. My employer, the Victorian Department of Primary Industries (DPI), deserves special mention for the support that was provided to undertake this project. Without this support I would have struggled to maintain domestic commitments whilst overseas. Russell Goodman (Senior Apicultural Officer DPI), I thank you wholeheartedly, personally and as a work colleague. I thoroughly appreciated your advice and positive encouragement for me to undertake this journey. I could not have selected a more appropriate Churchill professional referee. Likewise, Dr Denis Anderson (Principal Research Scientist - CSIRO), I m very grateful for your advice regarding suitable USA destinations, support and contributions as my Churchill project referee, as well as your ongoing efforts within the honey bee industry. I ll never be forgiven if I do not thank Joe Riordan (Leading Apiary Inspector DPI) for holding the fort in my absence. I m sure the pleasure will be returned! To all the US people who hosted me and so willingly shared their professional apicultural knowledge and experiences, I genuinely say thank you. I trust that our networks and shared interests will be long-lasting. Lastly, this positive experience would not have been possible without kind support from a friend and family back home. Thank you Joanne, my daughter Lily and son Erem. 3

4 1.2 Glossary AHBIC Australian Honey Bee Industry Council AQIS Australian Quarantine Inspection Service BAMs Beekeeper Applied Miticides CSIRO Commonwealth Scientific and Industrial Research Organisation DAFF Department of Agriculture, Fisheries and Forestry DfU Directions for Use DPI Department of Primary Industries (Victoria) DWV Deformed Wing Virus IVC Integrated Varroa Control PHA Plant Health Australia RHB Russian Honey Bee RIRDC Rural Industries Research and Development Corporation UMN University of Minnesota UMN University of Minnesota VSH Varroa Sensitive Hygienic behaviour 4

5 2. EXECUTIVE SUMMARY Mr Daniel Martin. PO Box 3100 Bendigo Victoria Mob Apiary Officer, Victorian Department of Primary Industries. Investigate best practice integrated Varroa mite control (IVC) for the future benefit of 2.1 Highlights Gaining invaluable IVC and apiary experience working with internationally renowned innovative commercial beekeeper, Randy Oliver, California. Participating in lab and field trials with United States Department of Agriculture (USDA) Bee Laboratory staff (including research team leader Dr Tom Rinderer) from Baton Rouge Louisiana. Working closely with USDA Bee Laboratory staff (including research team leader Dr Jeff Pettis) from Beltsville, Maryland. Assisting with field apiary inspections with Maryland Department of Agriculture Apiary Inspector Jerry Fischer. Participating in field research trials with staff (including research team leader Dr Marla Spivak) from the University of Minnesota (UMN) honey bee research team. Conducting video-cam interviews with USDA and UMN research team leaders, as well as leading industry beekeepers. 2.2 Key findings. Most USA beekeepers were completely and continually blindsided by varroa as it became regionally established (in feral/wild and managed honey bee colonies). Varroa mite levels within colonies/apiaries remains the priority management issue for beekeepers. Beekeepers acknowledge that they need to know their foe (varroa), have a full appreciation and intimate understanding of mite reproduction and behaviour (e.g. how the mite successfully exploits its host), whilst also accepting and adopting a living with varroa style of apiary management. Effective colony/apiary monitoring methods are essential for determining colony/apiary threshold mite levels and subsequent timing of efficient and cost effective IVC tools and strategies. Synthetic chemical treatments/beekeeper applied miticides (BAMs) are largely ineffective for the control of varroa due to mite populations developing resistance. Development and adoption of selective honey bee breeding programs for varroa sensitive hygienic (VSH) behaviour and holistic pest and disease management are invaluable long-term objectives of IVC and a future investment for healthier honey bee populations. Improved beekeeper colony/apiary husbandry/management practices play a key role in IVC. 5

6 2.3 Dissemination and implementation As a DPI Apiary Officer I have direct communication with Victorian DPI registered beekeepers. In my professional capacity I intend to: Develop pre and post varroa incursion Varroa-Wise education and training material for Victorian/Australian beekeepers. Pilot the delivery of pre varroa incursion Varroa-Wise education and training to selective Victorian beekeeping clubs/associations. Deliver on-going educational presentations at local, state and national apiary association meetings, field-days and conferences, as well as at agricultural and horticultural association conferences. Regularly contribute to industry journal publications. Provide authoritative advice to: - DPI Apiary Officers - Senior Biosecurity Victoria (DPI) staff - Plant Health Australia (PHA) Consultative Committee on Emergency Plant Pests - Australian Honey Bee Industry Council (AHBIC) Varroa Treatment & Preparedness Committee. 3. PROGRAMME 2 May to 6 May Randy Oliver - commercial beekeeper Grass Valley California USA 17 May to 28 May Dr Tom Rinderer and honey bee research team US Department of Agriculture Bee Laboratory, Baton Rouge Louisiana, USA May to 11 June 11 Dr Jeff Pettis and honey bee research team US Department of Agriculture Bee Laboratory, Beltsville Maryland, USA June to 20 June Dr Marla Spivak and honey bee research team The Bee Lab, Department of Entomology, University of Minnesota (UMN), Saint Paul Minnesota, USA. 6

7 4. INVESTIGATE BEST PRACTICE INTEGRATED VARROA MITE CONTROL (IVC) FOR THE FUTURE BENEFIT OF AUSTRALIAN BEEKEEPERS AND FARMERS 4.1 Australia s honey bee dependent pollination industry With the growing attention it deserves, the humble European honey bee (Apis mellifera) is rapidly claiming international attention. Heightened public awareness around the roles and importance of honey bees has been a major driver in cementing the fact that honey bees provide more than just honey. Photo 1. A healthy varroa-free European honey bee (Apis mellifera) undertaking almond pollination at Rovinvale, Victoria, Australia. (Photo Daniel Martin, Apiary Officer, DPI, Victoria) Honey bees are pollinating machines, responsible for servicing the demanding pollination needs of horticultural and agricultural pollination dependent industries. A RIRDC (2010) publication estimates that the European honeybee is involved directly or indirectly in 65% of agricultural production in Australia alone. Australian horticultural and agricultural industries support 35 crops that are dependent on honey bee pollination for optimum yield return. It is expected that varroa will progressively kill Australia s wild/feral honey bee populations (DAFF 2011). Incidental (free) pollination will disappear and there will be a significant shift towards dependence on managed honeybees for pollination services. As the number of wild/feral honey bee colonies declines, the horticultural industry sector will be most affected, with average losses estimated at $50 million a year (DAFF 2011) 7

8 Photo 2. Healthy varroa-free commercial honey bee colonies undertaking almond pollination at Robinvale, Victoria, Australia. (Photo Daniel Martin, Apiary Officer, DPI, Victoria) Photo 3. Healthy varroa-free commercial honey bee colonies undertaking almond pollination at Robinvale, Victoria, Australia. (Photo Daniel Martin, Apiary Officer, DPI, Victoria 8

9 4.2 Australia s vulnerable honey bee industry It is acknowledged by honey bee industry experts that it is only a matter of time before the economically devastating honey bee parasitic mite, varroa (Varroa destructor), becomes established in Australia. This is despite existing rigorous federal and state government exotic pest and disease surveillance programs (focussing on high-risk points of entry i.e. major shipping ports) that are the envy of other developed countries. Alarmingly, another varroa species, V. jacobsoni, occurs on Asian honey bees (Apis cerana), and was observed for the first time reproducing on European honey bees in Papua New Guinea (Goodman et al. 2010). Clearly, Australia s honey bee industry and associated plant health industries are under immediate threat. Australian beekeepers, the hobbyist in a suburban backyard, commercial migratory enterprises (500 colonies as a sole operator) and queen bee breeders are all in a very vulnerable, yet unique position. The chapter of beekeeping in the Australian Garden of Eden may soon close. Varroa changes everything. A large percentage of Australian beekeepers may decide that they are not up for the challenge, may be unable to cope with varroa and added financially demands. In reality, varroa will sort the wheat from the chaff. Beekeeper survivability will be tested. Photo 4. Healthy varroa-free European honey bees in Australia (Photo Daniel Martin, Apiary Officer, DPI, Victoria). For the benefit of, and to negate short and longterm adverse impacts form varroa, we should consider the equal importance of pre and post incursion preparation. Preparation is the key for increasing beekeeper survivability whilst also assisting with developing an increased capacity for future robust Australian honey bee populations. 9

10 Photo 5. Healthy varroa-free honey bee colonies belonging to a suburban Melbourne hobby beekeeper (Photo Daniel Martin, Apiary Officer, DPI, Victoria). Photo 6. Healthy varroa-free honey bee colonies belonging to a suburban Melbourne hobby beekeeper (Photo Joe Riordan, Apiary Officer, DPI, Victoria) 10

11 . Photo 5. Varroa on the thorax of an adult honey bee in the USA (indicated by green arrow). The bee immediately below has deformed wings a symptom of deformed wing virus. (Photo Daniel Martin, Apiary Officer, DPI, Victoria) Photo 6. Adult varroa mites (indicated by green arrows) parasitising Apis mellifera drone (male) pupa in the USA. (Photo Daniel Martin, Apiary Officer, DPI, Victoria) 11

12 4.3 The face of future beekeeping in Australia with varroa Our reliance on honey bees and their ensuing plight post varroa establishment will undoubtedly generate a focus on our beekeepers (hobbyists, part-time commercial and full-time commercial).their ability to maintain healthy honey bee populations will be in the spot light. Unfortunately, it is likely that many Australian beekeepers that will be affected by varroa, possibly per cent (mostly hobbyists and part-time commercial), will stop beekeeping (DAFF 2011). The remaining beekeepers will face immense challenges, particularly during periods (generally years 3 5 after varroa colonises a region) when wild/feral colonies are collapsing and their managed colonies are reinfested with varroa as a consequence of robber-bee activity (i.e. when bees from managed colonies rob weakened/collapsed wild/feral colonies thereby providing varroa the opportunity to hitch-hike in to managed colonies). Later, beyond approximately 6-10 years (based on overseas experiences), beekeepers are likely to face further heightened challenges when varroa develops resistance to synthetic chemical treatments (e.g. Apistan and Bayvarol miticide strips). Resistance to chemical treatments will result in significantly increased colony stresses as a direct result of increasing unchecked varroa levels. As mite resistance to registered (approved) synthetic chemical treatment develops and spreads beekeepers may turn to concocting their own synthetic chemical treatments/bams (beekeeper applied miticides). It s only a relatively short period before varroa develops resistance to these BAMs and beekeepers will again find themselves on an unforgiving treadmill of ineffective (and costly) management practices. Again, the beekeeper begins to suffer economically damaging colony losses, being left defenceless against the onslaught of varroa. Beekeepers will face concerns regarding comb and honey contamination, colony and queen health issues, and the lack of viable alternatives to the currently popular chemicals (Oliver 2011). The impact on colony health from varroa mismanagement, or rather the lack of known suitable long term effective control methods, now widens to include emerging unknown and known pathogens and viruses (e.g. DWV Deformed Wing Virus). Colony viral loads and other developing colony stress factors (e.g. poor nutrition, chill-stress, landscape pesticides and the presence of other inhive pests and diseases) now become the new-age major concern affecting colony health and the viability of apiary operations. As beekeepers scramble for the next varroa fix the comb contamination issue comes to the fore, with recent research, most as yet unpublished, indicating that miticide residues (often coupled with pesticide contamination) in combs wreak havoc with bee brood and colony immune competence (Oliver 2011). In other words, comb miticide/pesticide contamination negatively affects the ability of honey bees to sustain a healthy immune system. Awareness is growing amongst international beekeepers indicating that long term varroa management involves more than just dealing with a mite. Upon reflection, beekeepers admit that they missed the boat with regard to preparing for the short and long term impact of varroa. They will acknowledge however, that varroa continues to be the backbone of their problems. In other words, varroa control remains their priority management issue. 12

13 Photo 7. Dead brood from a USA colony. Brood is exhibiting symptoms of numerous known and unidentified viruses. Adult bees (indicated by green arrows) have failed to emerge from their brood cells. (Photo Daniel Martin, Apiary Officer, DPI, Victoria) Photo 8. Adult worker bee (indicated by green arrow) that, in a weakened state (likely as a result of increased colony viral loads), has failed to successfully emerge from a brood cell. (Photo Daniel Martin, Apiary Officer, DPI, Victoria) 13

14 Photo 9. An unproductive dwindling commercial US colony that has not been managed effectively to control in-hive varroa levels. Further inspection revealed abnormally high brood viral loads (refer Photo 10). (Photo Daniel Martin, Apiary Officer, DPI, Victoria) Photo 10. A brood frame from an unproductive commercial US colony. Note old darkened comb that may have been contaminated with synthetic chemical varroa treatment residues and/ or landscape pesticides over an extended period. Comb rotation is an important component of IVC. (Photo Daniel Martin, Apiary Officer, DPI, Victoria) 14

15 4.4 The case for IVC learning and development Despite the picture of gloom, increased beekeeper survivability has proven to be a positive reality in countries that have experienced varroa for many decades. In the case of the USA, varroa has been present since Most survivor beekeepers will readily admit to the constant evolving uphill varroa battle that still continues today, especially due to the increased presence of colony viral loads that are exacerbated by varroa. However, this core group of beekeepers (including hobbyists, part-time commercial and commercial) share the common beliefs that their survivability is attributed to: 1. Willingness of industry, government and beekeepers to learn from their own/international mistakes. 2. Beekeeper capacity to prepare for varroa well in advance of an incursion, or before the uptake/commencement of keeping bees. Beekeepers that are unaware or ignore the necessity of arming themselves with current, relevant and correct information will inevitably face high and repeated colony losses. 3. Beekeeper ability to accept, implement and adapt to change when varroa becomes established. Photo 11. Descriptive bee smokers! All beekeepers have a choice. The above 3 points provide sound and proven advice. (Photo Daniel Martin, Apiary Officer, DPI, Victoria) 15

16 Photo 12. A productive commercial US colony that is managed with IVC, excluding the use of synthetic chemical treatments. (Photo Daniel Martin, Apiary Officer, DPI, Victoria) Photo 13. A productive USDA research colony on the right next to a dwindling colony (left) that has been left untreated for varroa mite. (Photo Daniel Martin, Apiary Officer, DPI, Victoria) 16

17 It is widely acknowledged that there is no one sustainable silver bullet for varroa control. Rather, beekeepers require an IVC toolbox that includes key practical IVC management tools best suited to their individual apiary operations. The beekeeper must equip themselves with the necessary skills to operate the IVC tools and importantly, develop an in-depth understanding of the life cycle of varroa (and hence an understanding of mite life cycle weaknesses). When varroa establishes itself in Australia there will be a time lag before the mite becomes widespread. It is acknowledged that the spread of varroa will most likely be assisted by human movement (unintentional and perhaps intentional). In both the USA and NZ experience, varroa became widespread within both countries within an 8 year approximate timeframe. Knowing this, Australian commercial beekeepers, under the threat of varroa, will move quickly to protect their business interests. Their priority will be to maintain business continuity. In this case, it is likely that most commercial beekeepers may decide to employ the use synthetic chemical treatments. Awareness from international experience suggests that the move/preference towards employing and relying on synthetic chemical treatments should be considered with caution. There are several important factors to consider: Depending on the country of origin, Australia may experience an incursion of varroa that has already developed levels of resistance to some synthetic chemical treatments. Prolonging the effectiveness of synthetic chemical treatments relies heavily on beekeeper judicious application. Synthetic chemical treatments/bams will inevitably become ineffective against the control of varroa due to mites developing resistance High residue contamination risk to honey and other saleable hive products (wax, pollen and propolis) adversely affecting export markets and the green image of Australia s honey bee industry. A large majority of Australian beekeepers are understandably very daunted by the prospect of having to cope with varroa in the near future. The varroa subject is very broad and is often perceived as very complex. From a scientific point of view, this is true. However, in practice, planned successful IVC can be readily incorporated into small or large scale apiary operations. 17

18 4.5 IVC Objectives At some point in time (ideally well in advance of a varroa incursion), Australian beekeepers will have to take the first step and commence learning to prepare for and live with varroa. Some beekeepers have already taken this positive step (many have not!). The beekeepers that capitalise on this proactive approach will increase their capacity to manage varroa and lessen the risk of being overwhelmed, now and post incursion. Beekeepers need a starting point. In preparing for varroa Australian beekeepers would be wise to consider their future varroa management practices with short and long term views. An important objective of integrated varroa control (IVC) involves implementing practical apiary operations over short term and long term periods. These operations require flexible planning (often due to unpredictable seasonal influences that affect most commercial migratory beekeeping operations). IVC objectives should be considered as a pathway to living with varroa successfully. It can be said that successful beekeeping with varroa is as much as about spending more time managing your bees rather that dealing with the constant worry of managing mites. After all, beekeeping is about keeping bees, not keeping mites! Short term IVC objectives involve stabilising managed honey bee populations that are under immediate threat from varroa. Nobody wants to witness or be responsible for unnecessary colony death. This does not exclude the judicious use of approved synthetic chemical treatments or the use of synthetic treatments derived from natural products. Responsible short term IVC objectives should aim to support colony/apiary health and sustain business continuity through a period of transition towards a period in time where long term IVC strategies prove to become more effective, reliable and have a broader uptake by industry beekeepers. Long term IVC objectives largely focus on selectively breeding managed honey bee colonies that are productive and self-resilient against varroa. In other words, bees that exhibit varroa tolerance. Varroa tolerance is the ability of a honey bee colony to co-exist with an infestation of the mite (Goodwin & Taylor, 2007). Supporting productive varroa tolerant honey bee colonies to support themselves in their long term fight against varroa is an investment in future honey bee health and a country s honey bee industry. It takes considerable time and concerted effort to achieve and sustain this long term objective. In fact, it may be fair to say that Australian beekeepers may only begin to approach this ideal objective during, say, the first 10 years of post varroa incursion. Industry (all beekeepers including queen bee breeders), government and research organisations can play a significant role within moving towards this objective. IVC assists with this journey by encouraging beekeepers to avoid perpetuating the existence of feeble non-varroa tolerance honey bee colonies with the use of synthetic chemical treatments (M Spivak 2011 pers. comm., 18 June). Beekeepers who proactively embrace and evolve apiary IVC management practices that incorporate a dynamic living with varroa ethos are more likely to increase colony/apiary resilience against varroa. 18

19 The current state of Australia s honey bee stocks in terms of varroa tolerance is largely unknown, despite the likelihood that our stocks would exhibit little, if any, tolerance/resistance. This makes sense, our honey bees have not been exposed to varroa yet. As such, they have not had time to develop specific varroa sensitive hygienic (VSH) behaviour. For the benefit of Australian beekeepers, there is no reason why this process, involving selecting Australian honey bee stocks that exhibit hygienic behaviour, cannot commence immediately within Australia on local and regional levels. This can commence even in the absence of varroa! Selective breeding for hygienic behaviour can be as simple as selecting for honey bee colour. I will expand on this important topic further on in this report, under IVC tools and strategies: Selective honey bee breeding for (varroa) hygienic behaviour (pp 43-45). Importantly, in a period of pre varroa incursion, delay in selecting for hygienic behaviour equates to missed opportunity. It will be a failing of individual beekeepers, queen bee breeders and the Australian honey bee industry to ignore the present need to prepare well in advance with developing honeybee stocks that exhibit hygienic behavioural traits. Photo 9. A successful Varroa-wise USA commercial beekeeper and researcher, Randy Oliver, who practices IVC and has not used BAMs/synthetic chemical treatments over the past decade. (Photo Daniel Martin, Apiary Officer, DPI, Victoria) 19

20 Photo 10. US honey bees exhibiting varroa sensitive hygienic (VSH) behaviour. Worker bees detect that there is a problem with the developing larva/pupa (as a result of the presence of active varroa in the cell) and promptly remove the developing larva/pupa, thereby disrupting the mite s life cycle. Selective breeding for VSH behaviour is an important long term objective and invaluable IVC tool (Photo Daniel Martin, Apiary Officer, DPI, Victoria) 4.6 Key IVC objectives serve to: Reduce the potential for adverse impact on colony/apiary health from varroa Provide the beekeeper with practical, simple, effective and cost efficient colony/apiary mite monitoring skills Provide the beekeeper with an understanding and appreciation of safe/acceptable colony/apiary mite thresholds levels Provide the beekeeper with multiple mite treatment options that are effective and cost efficient over a beekeeper s calendar year Assist the beekeeper with encouraging colony/apiary mite competition Assist the beekeeper in planning ahead for timely effective treatment applications Encourage beekeepers to share information and coordinate timely treatment applications in apiaries that share localities 20

21 Encourage improved beekeeper colony/apiary husbandry practices Enhance the genetic variance of local and regional honey bee stocks, with specific intention to disperse and sustain beneficial honey bee hygienic behavioural traits (e.g. VSH and resistant Russian ) 4.7 IVC tools and strategies IVC tools and strategies can be grouped in to 5 main fields. They include: Know your foe (i.e. varroa) Colony/apiary mite monitoring Timely and judicious treatment applications Development and adoption of beneficial selective honey bee breeding Improved beekeeper colony/apiary husbandry/management practices. (a) Know you foe It s not good enough just to know what a varroa mite looks like. An integral part of successfully keeping bees with varroa involves the full appreciation and intimate understanding of how the mite operates and can successfully exploit its host. For example: Understanding the reproductive life cycle of varroa, and hence understanding varroa life cycle weakness (e.g. during colony broodless periods). This knowledge can be used for planning various IVC treatment applications/management practices that assists with further disrupting the reproductive life cycle of varroa. Appreciating how varroa travels/disperses (e.g. beekeeper assisted movement, robbing of dead-out/weakened colonies, drift within apiaries (i.e. between colonies) and between apiaries, bees absconding (flight over fight mode due to intolerable varroa colony infestation levels). 21

22 Figure 1. Reproductive life cycle of varroa mite. (Sourced from: Ministry of Agriculture and Forestry Biosecurity New Zealand) (b) Colony/apiary mite monitoring: Practical, simple, effective and cost efficient t s a sobering thought for beekeepers to realise and appreciate that varroa population growth rate within a colony that contains brood, if left untreated, will double every month. This exponential growth rate can result in colonies crashing/collapsing very quickly and unexpectantly. What the most successful beekeepers (hobbyist, part-time commercial and commercial) have found is that they can minimise losses by keeping tabs on varroa levels, and never allowing them to rise above a few per cent (mites per hundred bees) at any time of the year (Oliver 2011). A frequent mistake made by beekeepers is that they miss seeing mites (hitchhiker/phoretic mites) on bees in their colony/colonies. This visual assessment is 22

23 seemingly valid, despite the fact that spotting a mite on a bee is akin to looking for a needle in a haystack! This blind assumption often results in the colony/apiary being left untreated. In colonies that contain phoretic mites it is often too late for effective treatment. At this stage, there is likely to be a high presence of mites reproducing within sealed brood cells. Effective monitoring of colony/apiary mite levels is widely considered the No.1 assessment tool for determining safe/acceptable colony/apiary varroa levels. Accurate results from monitoring allow the beekeepers to make treatment decisions based on knowledge of actual infestation levels of mites on adult bees and within worker brood in an individual colony or entire apiary (Lee, Reuter and Spivak 2010). In order to gather an accurate trend (seasonal) snapshot of mite levels it is recommended to conduct monitoring biannually. It is best practice to undertake monitoring during spring and autumn. This is the time when varroa treatment applications are mostly required. Monitoring may be required during summer. For practicality, simplicity and accuracy, the alcohol mite wash has been tested and refined by beekeepers that successfully monitor colony/apiary mite levels. The following photo guide (with footnotes) provides an introductory how-to-do in order to construct your own mite monitoring shaker and undertake mite monitoring using the proven alcohol wash method. (c) Constructing your mite monitoring shaker Photo 13. Components of mite shaker. Simple to make your own! Refer instructions for mite shaker construction on page25. (Photos Daniel Martin, Apiary Officer, DPI, Victoria) 23

24 Photo 14 (above) & 15 (below). Views of the two polypropylene screw-top lids. 1/8 wire mesh/gauze is sandwiched between lid tops which are then melted/welded together. (Photo Daniel Martin, Apiary Officer, DPI, Victoria) 24

25 (c) Instructions for mite shaker construction: Acquire two identical plastic jars (standard peanut butter jars will suffice) with screw-top lids. Note: the lids are made of from polypropylene and cannot be glued. Carefully remove (by safely cutting) the inner section of the closed-end of the screw-top lids to acquire the desired effect (as shown in photo 14). Alternatively, you can acquire a neat cut by applying a heated open-ended tin (e.g. tomato tin of smaller diameter) to the screw-top lids in order to remove/melt-out them solid section of screw-top lids. Note: Take care when cutting or when heating-up and using the heated open ended tin. Cut out a 1/8 wire mesh/gauze and place (sandwich) between the two open screw-top lids (as shown in photo 14). Note: make sure the lid thread faces the correct way (i.e. outwards) so that both jars can be screwed on securely. The lids are made of from polypropylene and cannot be glued effectively. Therefore, you will need to heat weld them together (as shown in photo 15). A soldering gun is best suited for this purpose. You now have a functional mite shaker (as shown in photo 16, p 25). 25

26 Photo 16. Mite shaker the end product. (Photo Daniel Martin, Apiary Officer, DPI, Victoria) 26

27 (d) Mite monitoring procedure using the alcohol wash method Photo 17. Essential mite monitoring (alcohol wash) kit: plastic tub, strainer. ½ cup (125ml) measurer, shaker (as described and pictured in photos 13, 14,15 & 16), isopropyl rubbing alcohol (35% minimum alcohol concentration). (Photos Daniel Martin, Apiary Officer, DPI, Victoria) Photo 18. Prepare all necessary equipment. (Photo Daniel Martin, Apiary Officer, DPI, Victoria) 27

28 STEP 1: Photo 19. Contents of previous monitoring test (dead bees). Responsibly discard alcohol contaminated bees from your previous test. STEP 2: Clean both mite shaker jars thoroughly prior to use, and then pour fresh isopropyl rubbing alcohol into one of the mite shaker jars until it is approximately 2/3rds full. (Photo Daniel Martin, Apiary Officer, DPI, Victoria) Photo 20. It s acceptable to re- use alcohol from previous monitoring tests. If you choose to do this, make sure you pour the previously used alcohol in to the other thoroughly cleaned mite shaker jar through a strainer. This process eliminates the possibility of any mites contaminating the jar from previous tests and hence the possibility of false varroa counts. Make sure you then thoroughly clean the jar that contained the re-used alcohol. (Photo Daniel Martin, Apiary Officer, DPI, Victoria) 28

29 STEP 3: Photos 21 (above) & 22 (below). Shake bees from one brood frame in to the plastic tub. Note: Field bees will mostly fly out of tub immediately, leaving behind predominantly nurse bees which are likely to carry a greater quantity of phoretic mites. (Photos Daniel Martin, Apiary Officer, DPI, Victoria) 29

30 STEP 4: Photo 23. Make sure the queen is not in the tub if you have not previously located her on the frames prior to shaking the bees in to the tub. (Photo Daniel Martin, Apiary Officer, DPI, Victoria) STEP 5: Photo 24. Scoop ½ cup (125ml) of bees (approximately 300 bees) from the tub. (Photo Daniel Martin, Apiary Officer, DPI, Victoria) 30

31 STEP 6: Photo 25. Pour bees in to mite shaker jar containing the isopropyl rubbing alcohol (Photo Daniel Martin, Apiary Officer, DPI, Victoria) STEP 7: Photo 26. Screw the two mite shaker jars together firmly. (Photo Daniel Martin, Apiary Officer, DPI, Victoria) 31

32 STEP 8: Photo 27. Briefly maintain bees in bottom jar to soak in alcohol. (Photo Daniel Martin, Apiary Officer, DPI, Victoria) STEP 9: Photo 28. Invert shaker so bees are in now in the top jar. Shake vigorously for approximately20 seconds. It is essential to maintain vigorous shaking motion in order to keep the alcohol swirling with bees in top the top jar. (Photo Daniel Martin, Apiary Officer, DPI, Victoria) 32

33 STEP 10: Photo 29. Reduce vigorous shaking slowly to a slight jiggle in order to allow the alcohol to drain through the bees and down in to the bottom jar. (Photo Daniel Martin, Apiary Officer, DPI, Victoria) STEP 11: Photo 30. Raise bottom of jar to view any mites that have been dislodged from bees (indicated by green arrows). Photo Daniel Martin, Apiary Officer, DPI, Victoria) 33

34 (e) Interpreting field mite monitoring results for determining mite infestation levels (%) on colony/apiary adult bees. Interpreting field monitoring results is a simple mathematical process, as described by Oliver (2011) below. For a single colony: 1. Count the number of mites in the bottom of the jar 2. Divide the number of mites in the jar (sampled from 300 bees) by 3 to give the mite infestation percentage (mites per 100 bees). For example, if there are 12 mites present in the bottom of the jar:12 divided by 3 = 4. Therefore, this equates to a 4% mite infestation level for the colony sampled. For a larger apiary: 1. Sample (same as above for a single colony) across the apiary from 8 colonies. Sample every fifth colony in an apiary until the 8 colonies are sampled (this procedure is valid for apiaries with 24 to 84 colonies) (Lee, Reuter and Spivak 2010). Note: if the apiary contains more than 84 colonies it would make sense to adjust the number of colonies sampled. For example, if the apiary contained approximately 160 colonies, it would be advisable to sample 16 colonies total. 2. Calculate the mean percent mite infestation for the apiary. Oliver (2011) further importantly suggests: Always know your mite levels to avoid being surprised/caught off guard Sampling a few hives in each apiary throughout the seasons gives you an indication of the pace of mite population build-up. Attempt to keep levels below 6 mites (2%) during summer, and lower in autumn. Strive to maintain no more than 1 mite in a sample from a breeder queen colony. Commercial beekeepers would be wise to have a minimum of two mite monitoring shaker jar handy for use, so one can be settling on top of a hive whilst sampling has commenced from the next hive. 34

35 However, when interpreting results from sampling adult bees the beekeeper should be mindful that mites within brood cells have not been sampled. Results from extensive field trials and research conducted by Lee, Reuter and Spivak suggest that: the number of mites on adult bees can be multiplied by 1.8 to correct for the number of mites in worker brood. To simplify and err conservatively on the side of overestimation, we recommend using a correction factor of 2, or doubling the adult bee infestation level to estimate the mite infestation in a colony. If there is no brood, then no correction factor is needed. If there is an abnormally high amount of worker or drone brood relative to adult bees, there is a possibility the correction factor could lead to an underestimate of total mite load. (Lee, Reuter and Spivak 2010). Table 1. Number of mites found in a sample of 300 adult bees and the corresponding colony mite density after the correction (doubling) factor is applied, and the number of mites found in eight 300 adult bee samples and the corresponding apiary mite density after the correction (doubling) factor is applied. (Source from: Lee, K, Reuter, G & Spivak, M 2010, A Standardised Sampling Plan to Detect Varroa Density in Colonies & Apiaries ) 35

36 (f) Treatment applications Within this section of the report my intentions do not include recommending particular varroa treatment products. Nor is it appropriate that I expand on merits of one treatment type over another. Rather, and more importantly, I will discuss how various treatments can be responsibly used within IVC, and have been proven to be effective within IVC in the USA. IVC may include, but is not bound by, the use of all 3 main categories of treatments. These include: 1. Synthetic chemical treatments (e.g. Apistan miticide strips). 2. Synthetic treatments derived from natural products (e.g. formic acid, oxalic acid, thymol gel). 3. Organic treatments (e.g. essential oils). All 3 treatment categories and individual specific treatments have their positives and negatives. Importantly, in particular reference to synthetic chemical treatments, reducing treatments to only those necessary is imperative to keeping costs down, reducing hive contamination, and slowing the development of mite resistance to new miticides (Lee, Reuter and Spivak 2010). Oliver (2007) expands on the positives and negatives of synthetic chemical treatments by mentioning that: They are smart in that they eliminate the need for the beekeeper to understand the mite. They are easy to apply, relatively safe to use, and generally don t get into the honey to any degree. They are relatively inexpensive both in material cost, and for the labor required for application. If the public gets a notion that they are tainting honey, we could kill the market for several years. If we find out that their residue in the combs is harmful to bees, we might have to junk the combs. If you don t notice when mites have developed resistance, your colonies can crash in a hurry. As long as we use them, we are inadvertently breeding for virulent mites that spread by mainly by killing colonies. (Oliver 2007). 36

37 Informed treatment product choice is an important component of IVC. IVC provides a range of varroa treatment options for the beekeeper, and in doing so, does not lock the beekeeper in to blanket (whole of apiary) calendar treatments using only a single treatment product. This is particularly important where there is a beekeeper preference for initial use of synthetic chemical treatments. Australian beekeepers are likely to react quickly (understandably) to a varroa incursion, with the majority of beekeepers selecting synthetic chemical treatments in order to protect their business interests. However, the message from overseas experience from decades of use/misuse of synthetic chemical treatments s clear; Beekeeper beware! There is no purpose in continued application of a treatment that is losing its effectiveness and/or may lead to the wider detriment of colony/apiary heath (short and/or long term).this is a cost inefficient exercise. When varroa becomes established in Australia there may be a case for the use of synthetic chemical treatment products whose mode of action spans more than one mite reproductive cycle (~ 12 days), thus killing phoretic mites as they emerge from the safety of brood cells (Oliver 2011). It is recommended that Australian beekeepers seriously consider their decision to prolong the use of synthetic chemical treatments beyond a tipping point that will inevitably lead to mite resistance to synthetic chemical treatments. IVC, with colony/apiary mite monitoring playing a major role, assists beekeepers to select multiple treatment applications that best suit their apiary operations over short and long term periods. Effectively, IVC serves as a lever, allowing the beekeeper to initiate a shift (transition) over a period of time towards using softer treatments (i.e. synthetic treatments derived from natural products) as opposed to synthetic chemical treatments. Like many US commercial beekeepers, the Australian beekeeper will be afforded opportunity to move away from their dependence on synthetic treatments. By using an IVC toolbox that contains multiple varroa treatment product options the beekeeper: Avoids perpetuating week colonies/apiaries that are dependent on synthetic chemical treatments that will inevitably become ineffective against varroa (due to resistance). Encourages mite competition within a colony/apiary, thereby increasing the effectiveness of various treatments. Rotational use of treatments (especially synthetic chemical treatments) assists with this process. Provides flexibility to beekeeper to use specific treatments that are legally permitted for use within a colony whilst the bees are on a honey flow. Reduces the risk of hive product (honey, pollen, wax, propolis) contamination, particularly from chemical residues (very important for domestic and export market integrity). Reduces the risk of comb contamination, particularly from chemical residues, that may exacerbate future problems associated with delayed brood development (and hence increased varroa reproductive life cycle opportunity within capped brood cells) and colony viral and pathogen loads. 37

38 Photo 31 (above) & 32 (below). Mite-Away Quick Strips (controlled release formic acid gel pads) - an effective synthetic treatment (derived from a natural products) if used correctly according to the approved label Directions for Use (DfU). (Photo Daniel Martin, Apiary Officer, DPI, Victoria) 38

39 Photos 33 (above) & 34 (below). Application of Mite-Away Quick Strips (controlled release formic acid gel pads) - an effective synthetic treatment (derived from a natural product) if used correctly according to the approved label DfU. (Photo Daniel Martin, Apiary Officer, DPI, Victoria) 39

40 Photo 35. Apiguard (thymol gel)) - an effective synthetic treatment (derived from a natural product) if used correctly according to the approved label DfU. (Photo Daniel Martin, Apiary Officer, DPI, Victoria) Photo 36. Application (using hive tool) of Apiguard (thymol gel)) - an effective synthetic treatment (derived from a natural product) if used correctly according to the approved label DfU. (Photo Daniel Martin, Apiary Officer, DPI, Victoria) 40

41 Photos 37 (above), 38 & 39 (below). Application of Apiguard (thymol gel)) - an effective synthetic treatment (derived from a natural product) if used correctly according to the approved label DfU. The provided cardboard card used for scooping the thymol gel can remain in the hive as the bees will remove (chew-out) over time. (Photo Daniel Martin, Apiary Officer, DPI, Victoria) 41

42 Encouragingly, overseas, through extensive field trials/research work, treatment product development (particularly with synthetic treatments derived from natural products) has advanced to allow commercial availability of improved user-friendly (including beekeeper occupational health and safety) treatment products that are also non-detrimental to colony health if used correctly according to the approved label Directions for Use (DfU). For good reasons, many Australian beekeepers may have a strong preference for synthetic treatments derived from natural products. However, in the past, overseas beekeepers have often experienced negative results using such approved treatments (e.g. formic acid). This has often resulted from incorrect use of the specific treatment (i.e. incorrect timing, incorrect dosage rates, non-compatible hive temperature for treatment s safe/effective active ingredient release). Unfortunately, this has often lead to other beekeepers shying away from considering the use of treatments within the natural category, preferring to go-it-alone with synthetic chemical treatments/bams. At this point, beekeepers should not be relying on new miticides effecting 95% kills that will be rendered ineffective due to resistance in four years, but rather, requesting and using less lethal miticides and/or synthetic treatments derived from natural products that we can use sustainably for the long term (Oliver 2007). Oliver provides a wise statement with: Beekeepers desperate to save their colonies sometimes resort to desperate measures. Don t let your colonies get to the point of desperation, and don t let desperation cloud your judgment. (Oliver 2007). Over the long term it is widely accepted that the road to successful Australian beekeeping with varroa in conjunction with reduced reliance on treatments involves the development and adoption of selective honey bee breeding programs that encourage varroa sensitive hygienic behaviour (VSH).Transition towards this goal whilst maintaining a viable honey bee industry will require our beekeepers to provide a helping hand to their colonies by implementing responsible and timely IVC treatment applications. For most Australian beekeepers, the varroa treatment learning curve will be very steep one indeed. Our beekeepers, in dealing with the uninvited hive guests, would be wise to adopt best practice IVC treatments whilst capitalizing on varroa treatment mistakes that have been made in the USA over the past decades. Equally as important, Australian beekeepers should consider advanced (in terms of safety and efficacy) IVC treatment applications that are now widely employed in apiary management in the USA. 42

43 (g) Selective honey bee breeding for (varroa) hygienic behaviour As previously mentioned in this report under 4.5 IVC Objectives (pp 18-20), living successfully with varroa in to the future will involve the development and adoption of selective honey bee breeding programs for (varroa) sensitive hygienic behaviour (VSH). VSH bees have a simple tactic for fighting varroa - they simply detect varroa in an uncapped cell, uncap the cell, chew out the parasitized pupa and disrupt the mite s reproductive life cycle (as shown in Figure 2. p. 45) (Oliver 2007). Increased activity of this nature in a colony/apiary should be encouraged (by the beekeeper) in the fight against varroa. VSH is a highly desirable trait that requires serious beekeeper and industry commitment over a prolonged period. Honey bees are not like sheep or cows which can be confined in paddocks for selective desirable breeding purposes. Due to their reproductive life cycle, including swarming, honey bees can have geographically broadened gene pools. It is likely that when varroa establishes in Australia our existing honey bee stock will exhibit little, if any, hygienic behaviour towards varroa. Over time, beekeepers should aim to select and breed from productive colonies that exhibit initial signs of VSH. In other words, non-vsh (non-performing/weak) colonies should not be selected for continued breeding lines. It doesn t appear that lack of production is a necessary fault if one makes a point of breeding only from the strongest and most productive colonies (Oliver 2007). In order to do this, there has to be desirable genetic stock available locally and regionally. Without genetic variance beekeepers will have nothing to work with. In this instance, beekeepers are limited to: Relying completely on the build-up of natural VSH from wild/feral and survivor managed colonies (likely to be waiting for an extended period with few productive colonies!) The legal importation of desirable VSH genetic material. This can be complicated due to presence of identified and unidentified viruses within honey bee colonies from the country of origin. Australian Quarantine Inspection Service (AQIS) is responsible for the development of honey bee importation protocols. AQIS protocols will have to be strictly followed. Pre-determining the need (in the absence of varroa) to employ apiary management strategies that incorporate rigorous selective breeding procedures from their own performing colonies, with particular reference to selecting productive colonies that exhibit pest and disease tolerance/hygienic behavioural traits (e.g. hygienic behaviour towards Chalkbrood disease Ascosphaera apis). In the latter point there is a very strong positive message for commercial queen bee breeders and also beekeepers that raise their own queens. That is, selecting for desirable hygienic behaviour, even pre varroa incursion, has great merit as a proactive varroa preparedness tool. When we have varroa, this mode of selective breeding should continue. The only difference will be that queen breeders/beekeeper 43

44 will then focus on selectively breeding from healthy and productive colonies that maintain consistently low varroa levels Churchill Fellow Tiffane Bates reminds us that: The challenge is to find traits and/or bee stock that can ultimately survive varroa infestation and produce healthy active colonies whilst reducing chemical use. Crucially these bees must also be commercially viable in terms of production and temperament. (Bates 2010). Photos 40. A productive USA breeder queen (indicated by green arrow) selected for varroa sensitive hygienic (VSH) behaviour. (Photo Daniel Martin, Apiary Officer, DPI, Victoria) 44

45 Figure 2. The process of honey bee varroa sensitive hygienic behaviour (VSH). (Sourced from: (h) Testing for hygienic behaviour Hygienic behaviour is genetic trait of honeybees and is used as their main defence against brood diseases, such as American foulbrood (Paenibacillus larvae) and Chalkbrood (Ascosphaera apis) (Reuter and Spivak 2010). The practical nature of testing for hygienic behaviour should allow beekeepers (regardless of number of colonies kept) to readily incorporate the procedure in to existing apiary operations. Testing for hygienic behaviour is not a complex operation. It essentially involves freezing a section of sealed pupae and recording how many dead pupae the bees remove within 24 hours (Reuter and Spivak 2010). High quantities (preferably 100%) of killed brood removed by bees over the 24 hour period indicates a colony that has increased hygienic behaviour. These colonies that exhibit desirable hygienic traits are then recorded as potential future breeder colonies. The following photos (with footnotes) from pp are from my field experiences with Marla Spivak (honey bee research team leader) and the research team from the University of Minnesota. This experience provided me with the basic underlying principles and steps involved in testing for hygienic behaviour. 45

46 Photos 41 (above) & 42 (below). Testing for hygienic behaviour using liquid nitrogen to Freeze kill brood in the field. (Photo Daniel Martin, Apiary Officer, DPI, Victoria) 46

47 As you will notice, the photo-illustrated method involves the use of liquid nitrogen for rapid field killing of brood (in order to simulate the presence of diseased/varroa infected brood). Note: For safety reasons, extreme caution is required when handling liquid nitrogen. An alternative method to using liquid nitrogen: Liquid nitrogen is not readily accessible and/or a practical resource for most beekeepers. Despite this, there is an equally effective alternative method that beekeepers can employ for freeze killing brood. This method simply involves cutting out a section of sealed brood containing approximately 100 capped cells (containing 3-10 day old pupae) on each side of the brood frame and then placing in a freezer at least -23º Celsius for hours (Reuter and Spivak 2010). After hours in the freezer the dead brood section can be returned to the hive by inserting back in to the frame. The hygienic behaviour test can now continue (refer p. 45). Photo 43. Testing for hygienic behaviour - carefully applying liquid nitrogen to brood frames. (Photo Daniel Martin, Apiary Officer, DPI, Victoria) 47

48 Photo 44 (above ) & 45 (below). Sample brood that has been selected for hygienic testing and killed by applying liquid nitrogen. (Photo Daniel Martin, Apiary Officer, DPI, Victoria) 48

49 Photo 46. Sampled brood after 24 hours. High percentage of remaining capped, perforated and chewed pupae indicates a colony that has reduced hygienic behaviour. (Photo Daniel Martin, Apiary Officer, DPI, Victoria) Photo 47. Sampled brood after 24 hours. 100% removal of liquid nitrogen killed brood Indicates highly desirable hygienic behaviour. This colony would be recorded as potential future breeder colonies. (Photo Daniel Martin, Apiary Officer, DPI, Victoria) 49

50 (i) Improved beekeeper colony/apiary husbandry/management practices Varroa is an equalizer for all beekeepers. Effectively, it sorts the men from the boys (and women from the girls!). Varroa knows no boundaries and therefore does not distinguish between colonies, apiaries or beekeepers for that matter. IVC can provide the beekeeper with the tools and skills that are essential for surviving with varroa. Beekeepers can enhance the results of IVC by improving colony/apiary husbandry/management practices. In reality, without varroa, Australian beekeepers are already striving for this goal. There are some basic influences regarding colony/apiary husbandry/management practices that have been proven to be notably beneficial for colony/apiary health when dealing with the added pressure from varroa. Importantly, these influences can be directly controlled by the beekeeper. As photo illustrated below, these included: include: Limiting the number of colonies that are contained in a single apiary. This practice: Reduces the spread of varroa by bees which may naturally drift between colonies Reduces the risk from the spread of varroa by honey bee robbing activity in the event of a colony becoming weekend and/or collapsing from varroa infestation. Photo 48. An apiary in Grass Valley, California. Smaller dispersed apiaries are preferable for limiting varroa drift/spread between colonies/apiaries. (Photo Daniel Martin, Apiary Officer, DPI, Victoria) 50

51 Annual requeening and nucleus colony production. These practices: Maintain existing colonies with productive young queens, thereby enhancing colony varroa sensitive hygienic (VSH) as well as enhancing other pest and disease hygienic behavioral traits Maintains reliable supply of next year s/season s production hives. Increases the genetic variance for future desirable VSH breeding stock. Can allow for the beekeeper to create queenless periods (3 weeks maximum) within existing colonies and nucleus colonies, thereby creating a predictable broodless period that in turn disrupts the reproductive life cycle of any present varroa. In the USA, nucleus colonies that are managed with this practice are termed walk-away splits, inferring that the beekeeper can walk away from the newly created nucleus colonies knowing that they will experience a guaranteed broodless/varroa reproduction free period, prior to requeening. Photo 49. Queen cell production. Queen cells are indicated by green arrows. (Photo Daniel Martin, Apiary Officer, DPI, Victoria) 51

52 Photo 50. An alternative method of queen cell production. Queen cells are indicated by green arrows. (Photo Daniel Martin, Apiary Officer, DPI, Victoria) Photo 51. Requeening existing colonies and queen-righting (providing) nucleus colonies with queen cells. (Photo Daniel Martin, Apiary Officer, DPI, Victoria) 52

53 Photo 52. Requeening existing colonies and queen-righting nucleus (queenless) colonies with queen cells. (Photo Daniel Martin, Apiary Officer, DPI, Victoria) Photo 53. Production of nucleus colonies to replace production hives that have weakened/collapsed due to over-winter unsuccessfully and/or due to losses from varroa. (Photo Daniel Martin, Apiary Officer, DPI, Victoria) 53

54 Drone comb monitoring and drone comb removal/trapping: This practice: Allows the beekeeper to monitoring the presence of varroa levels in drone comb, which is more conducive to the reproductive life cycle of varroa due to the longer period that drone cells remain capped (24 days). Note: Drone comb monitoring is not a reliable method of determining accurate colony/apiary mite infestation levels. This method should only be used as a quick assessment tool if looking for varroa on brood frames where drone brood is present. Interestingly, colonies that exhibit low mite levels in drone brood may actually contain desirable VSH traits that are presently at work in the colony. In this case, it would be unwise for the beekeeper to remove/kill drone brood from this colony. It is preferable to allow the colony s drones to pass-on this desirable trait to other virgin queens. When required, allows the beekeeper to remove significant quantities of reproducing varroa quickly and efficiently. Also assists with spring colony/apiary swarm control, and therefore indirectly assists with minimizing varroa drift between colonies and within apiaries. Photo 54. Varroa present in drone comb. (indicated by green arrows. (Photo Daniel Martin, Apiary Officer, DPI, Victoria) 54

55 Photo 55. Removal of drone pupae for quick visual assessment for presence of varroa. (Photo Daniel Martin, Apiary Officer, DPI, Victoria) Photo 56. Drone pupae with varroa present (indicated bt green arrows). (Photo Daniel Martin, Apiary Officer, DPI, Victoria) 55

56 Photos 57 (above) & 58 (below). Removal of drone comb containing varroa infested drone brood. The frame can then be immediately returned to the hive. (Photo Daniel Martin, Apiary Officer, DPI, Victoria). 56

57 The use of screened/wire mesh bottom boards for varroa control. This practice: Relies completely on natural and/or beekeeper colony assisted mite drop. DOES NOT serve (contrary to widespread belief) as an effective or cost efficient tool for varroa control. Whilst still popular in the USA amongst hobbyists, commercial beekeepers have moved away from the use of screened/wire mesh bottom boards, choosing to return to the use of closed bottom boards. In addition to being ineffective for varroa control, screened bottom boards can also be detrimental to winter and spring colony management (Hendrickson 2011). Photos 59 (above) & 60 (below). Screened/wire mesh bottom boards. (Photo Daniel Martin, Apiary Officer, DPI, Victoria). 57

58 Availability of ample stores (preferably honey) and balanced honey bee nutrition all year round. This practice: Provides the necessary food and nutritional requirements that significantly assists the colony to survive and maintain productivity, and importantly, not suffer from stress (particularly whilst over-wintering and during the spring colony build-up period). Honey bees suffering from stress, with compromised immune system competence as a result of stress factors, can be a recipe for disaster. Varroa added to this equation is a sure recipe for disaster! Photos 61 (above) & 62 (below). Ample pollen stores enhances honey bee balanced nutrition (Photo Daniel Martin, Apiary Officer, DPI, Victoria). 58

59 Providing a dry warm house (hive). This practice: Assists the colony to maintain optimum hive temperature and reduce colony stress during winter. Reduces colony susceptibility to stress from to un-seasonal cold snaps which may cause adult bees to re-cluster, resulting in chilled brood. Assists overall colony health and prolongs adult bee lifespan, which is particularly vital for colony survival during winter. Enhances colony capacity for late Winter/early spring population build-up. Photos 63. Over-wintered hives in the USA. Note: various stages of snow melt on hive lids can indicate colony population strength/colony health status (Photo Daniel Martin, Apiary Officer, DPI, Victoria). 59

60 5. CONCLUSIONS When varroa mite becomes established in Australia there will be a radical departure from pre incursion beekeeping practices. A considerably high percentage of beekeepers (mostly hobbyists and part-time commercial but not excluding commercial) will struggle to maintain healthy honey bee colonies. Many of these beekeepers may decide to discontinue keeping bees. In many cases, varroa mite will make this decision for them. Varroa mite levels within colonies/apiaries remains the priority management issue for beekeepers in the USA (and likely most other countries). This situation will be no different for Australia beekeepers post varroa incursion. 4. Best practice integrated varroa control (IVC) can offer beekeepers the opportunity to implement and develop short and long term apiary management practices that are effective and cost efficient. It is possible to live successfully with varroa! Colony/apiary monitoring methods are essential for determining colony/apiary threshold mite levels and subsequent timing of efficient and cost effective IVC tools and strategies. Synthetic chemical treatments/beekeeper applied miticides (BAMs) will inevitably become largely ineffective for the control of varroa due to mite populations developing resistance. Responsible and judicious use of such treatment products will prolong their efficacy. Development and adoption of selective honey bee breeding programs for varroa sensitive hygienic (VSH) behaviour and holistic pest and disease management are invaluable long-term objectives of IVC and a future investment for healthier Australian honey bee populations. Improved beekeeper colony/apiary husbandry/management practices play a key role in IVC. Dissemination and implementation As a DPI Apiary Officer I have direct communication with 2400 Victorian apiarists. In my professional capacity I intend to: Develop pre and post varroa incursion Varroa-Wise education and training material for Victorian/Australian beekeepers. Pilot the delivery of pre varroa incursion Varroa-Wise education and training to selective Victorian beekeeping clubs/associations. Deliver on-going educational presentations at local, state and national apiary association meetings, field-days and conferences, as well as at agricultural and horticultural association conferences. Regularly contribute to industry journal publications. 60

61 Provide authoritative advice to: - DPI Apiary Officers - Senior Biosecurity Victoria (DPI) staff - Plant Health Australia (PHA) Consultative Committee on Emergency Plant Pests - Australian Honey Bee Industry Council (AHBIC) Varroa Treatment & Preparedness Committee. 6. RECOMMENDATIONS That the Australian honey bee industry unite (pre and post varroa incursion) for the common varroa cause, and in collaboration with government, prepare well in advance for varroa becoming established in Australia. That the Australian honey bee industry, along with other honey bee affiliated industries/organisations (e.g. honey bee dependent pollination industries), welcome and support authoritative advice regarding varroa and integrated varroa control objectives, tools and strategies. Australian beekeepers should avoid becoming overwhelmed with the broad (and often complex and negative) topic of varroa. Becoming overwhelmed will only lead to a sense of helplessness. Rather, beekeepers should proactively arm themselves with correct and current varroa information, with particular reference to best practice integrated varroa control. This should, in most part, involve beekeepers taking ownership of their learning regarding the subject matter. Where possible, beekeepers should proactively seek-out and become involved with DPI Victoria Varroa-Wise education and training programs that may be available in the future. Australian beekeepers should position themselves to learn from, by-pass and move forward from varroa management mistakes that have been blindly made overseas (particularly in the USA) over the past decades. In particular, these mistakes surround the use/misuse of synthetic chemical treatments. Australian beekeepers will need to know their foe (varroa), have a full appreciation and intimate understanding of mite reproduction and behaviour (e.g. how the mite successfully exploits its host), whilst also accepting and adopting a living with varroa style of apiary management when varroa becomes established in their apiaries. Australian beekeepers and queen bee breeders would be wise to initiate and further develop (in the absence of varroa) honey bee breeding programs that focus on rigorous selective breeding for productive colonies that exhibit desirable pest and disease tolerance/hygienic behavioural traits. 61

62 Photo 64. The European honey bee (Apis mellifera) - a pollinating machine! (Photo Daniel Martin, Apiary Officer, DPI, Victoria). Photo 65. European honey bees at hive entrance. (Photo Daniel Martin, Apiary Officer, DPI, Victoria). 62