New Zealand Beekeeper May 2017

MAY 2017 | VOLUME 25 No. 4

Manuka honey definition and export requirements released Ministry for Primary Industries

GWA honey dew honey Steve Howse Varroa treatments Dr Pablo German

What’s the use of pollen? Dr Linda Newstrom-Lloyd Beekeepers on the front line of surveillance Frank Lindsay

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NEW ZEALAND BEEKEEPER, MAY 2017

TABLE OF CONTENTS

Varroa treatments: mode of action and resistance

Manuka honey definition under the spotlight MPI begins consultation on science-based definition for manuka honey and new export requirements Education and Skills for Jobs Focus Group under way 11 Photo essay: flooding at Te Aroha, Waikato 13 What we have learned about giant willow aphid honeydew honey 15 4 6 9 Myrtle rust found on Raoul Island trees

19 23

What’s the use of pollen?

Apiculture health and safety programme formed AgriSea gets grant to study bees’ nutritional needs Waikato field day a great success

31 34 35

From the colonies

NIWA seasonal climate outlook 39 Beekeepers at the front line of surveillance 41

Front cover: Flooding again inundated parts of New Zealand as a result of cyclones Debbie and Cook in April 2017. Jo Telfar took this photo of beehives on her Te Aroha, Waikato property. See photo essay on page 13.

EDITORIAL/PUBLICATION (excluding advertising): Nancy Fithian 8A Awa Road, Miramar, Wellington 6022 Mobile: 027 238 2915 Fax: 04 380 7197 Email: editor@apinz.org.nz ADVERTISING INQUIRIES: Certa Solutions, PO Box 2494, Dunedin 9044. Phone: 0800 404 515 Email: beekeeper@certasolutions.nz PUBLICATIONS FOCUS GROUP: Frank Lindsay 26 Cunliffe Street, Johnsonville, Email: lindsays.apiaries@clear.net.nz DEADLINES FOR ADVERTISING AND ARTICLES: Due on the 6th of the month prior to publication. All articles/letters/photos to be with the Editor via fax, email or post to Nancy Fithian (see details above). Articles published in The New Zealand BeeKeeper are subject to scrutiny by the Apiculture New Zealand Management Team. The content of articles does not Wellington 6037 Ph: 04 478 3367

The New Zealand BeeKeeper is the official journal of Apiculture New Zealand (Inc.). ISSN 0110-6325 Printed by Certa Solutions, PO Box 2494, Dunedin 9013, New Zealand ApiNZ website: www.apinz.org.nz

necessarily reflect the views of Apiculture New Zealand. © The New Zealand BeeKeeper is copyright and may not be reproduced in whole or in part without the written permission of the Publisher, Apiculture New Zealand (Inc.). CONTACTS TO THE NEW ZEALAND BEEKEEPING INDUSTRY: Rex Baynes, AFB PMP Manager PO Box 44282, Lower Hutt 5040 Email: rbaynes@ihug.co.nz Ph: 04 566 0773 American Foulbrood Management Plan www.afb.org.nz

MANAGEMENT TEAM: Chief Executive Officer Karin Kos Email: ceo@apinz.org.nz Secretary Natasha Thyne Email: info@apinz.org.nz Accounts and Subscriptions Pauline Downie Email: memberships@apinz.org.nz PO Box 25207, Featherston Street,

AsureQuality Limited Phone: 0508 00 11 22 www.asurequality.com EXOTIC DISEASE AND PEST EMERGENCY HOTLINE 0800 80 99 66 www.biosecurity.govt.nz

Wellington 6146 Ph: 04 471 6254 APICULTURE NZ BOARD REPRESENTATIVES: Dennis Crowley

Barry Foster Stuart Fraser Sean Goodwin John Hartnell Ricki Leahy

Pollinator Incident Reporting Form: http://www.epa.govt.nz/Publications/ Pollinator_incident_reporting_form_2014. docx

Peter Luxton Russell Marsh Paul Martin Bruce Wills (Chair)

NEW ZEALAND BEEKEEPER, MAY 2017

MANUKA HONEY SCIENCE DEFINITION UNDER THE SPOTLIGHT CHIEF EXECUTIVE’S REPORT Karin Kos, Apiculture New Zealand Chief Executive The Ministry for Primary Industries’ long-awaited release of its scientific definition of mānuka honey has seen a lot of activity behind the scenes as members work through what it will mean for them, their businesses, their customers and for our industry overall.

That has meant seeking information from our members, and we’re very appreciative of those ApiNZ members who have openly shared their lab test results with the group. Another important aspect of the public consultation is MPI’s workshops being held around the country. You’ll see these outlined on page 6. I encourage you to attend and make the most of that opportunity. We are only going

We were pleased that MPI opened up the science definition for industry review and consultation which ends soon, on 23 May. To make the most of this, Apiculture NZ has established an expert review team, made up of our Standards, Compliance and Regulatory Focus Group, along with a number of science advisors. This group has been busy undertaking due diligence on the definition and at the end of this process will deliver an industry-wide ApiNZ submission to MPI.

Apiculture New Zealand shares MPI’s objective in having a robust definition that will give consumers confidence that they are purchasing authentic mānuka honey sourced from New Zealand. Having a clear, tight and widely endorsed approach to the identity of New Zealand mānuka honey will also give our international partners confidence in our ability as an industry and country to protect the integrity of this product.

FACTS AND STATISTICS

Mānuka Honey Science Programme 2014-2017

MPI SCIENCE DEFINITION

1 ST

3 independent experts from New Zealand, Australia and

government in the world to invest in a robust science programme to develop a scientific definition for any type of honey

Canada conduct peer review of key aspects of the science programme

12 More than

Nectar, leaf and pollen samples collected from over 700 plants representing 29 species from 12 regions

804 honey samples collected from the past 7 production years: approximately 120 New Zealand beekeepers, honey producers and 16 other countries

scientific organisations provided expertise to the programme

A combination of five attributes

test results produced and over 1,000 statistical analyses performed 10,000 Over

in New Zealand and 5 States in Australia

( 4 chemicals, 1 DNA marker from mānuka pollen) are required to authenticate monofloral

different honey types collected and tested 20 Over

and multifloral mānuka honey

18 different data sets representing over

11,000 honey samples from industry and MPI funded work were used to help scope the programme

14 chemical attributes Investigation of previously identified

Plant samples collected during 2 flowering seasons :

MPI starts Mānuka Honey Science Programme in 2014

new laboratory test methods developed

8 pilot projects funded to identify suitable approach

NEW ZEALAND BEEKEEPER, MAY 2017

ApiNZ Chief Executive Karin Kos and Life Member Pauline Bassett flanked by Clare and Tane Bradley of AgriSea. Photo: Rachel Scrimgeour, AgriSea.

FAREWELL TO TERRY GAVIN Terry Gavin, a past president of the National Beekeepers Association and life member, passed away in Whangarei in April, aged 87. Contact details for Terry’s family are: Gavin Family PDC Private Bag, Titoki Whangarei 0172 Ph: 09 433 1893 or John: 021 408 450 Our condolences go out to the Gavin family and to his many friends in the industry. We will publish a remembrance of Terry’s life in an upcoming edition of the journal. Pat and Terry Gavin at the first New Zealand Apiculture Industry Conference, Wanganui, 2014. Photo: Frank Lindsay.

to get one shot at this and it’s important we get it right—that means being proactive and upfront with our views and concerns. It also means taking the time to put in your own submission through MPI. We know there will be challenges with implementing the definition. Our approach has been to look at solving those challenges in the best interests for the future of the New Zealand mānuka honey industry. The value of field days Over the last few months, I’ve been privileged to attend and speak at a number of field days organised by local hubs and which have attracted large numbers of people, mostly hobbyists and new beekeepers. I’ve been hugely impressed with the quality of the days, the speakers, the relevancy and practical

nature of the topics and the enthusiasm of passionate people willingly sharing their knowledge and wisdom. These field days present a great opportunity to meet and hear from members, get members on board and for the ApiNZ Hubs to showcase the industry in a positive and supportive light. At the ApiNZ Waikato Hub field day in Thames, I particularly enjoyed talking to a father and son about the career opportunities this industry presents, including our upcoming apprenticeship scheme. At times we hear about the negative aspects of our industry’s growth. However, if these field days are anything to go by, there’s certainly a lot of positives in being part of a dynamic primary industry, one that people want to be a part of, and get great enjoyment from, whether it’s their hobby or business.

NEW ZEALAND BEEKEEPER, MAY 2017

MPI

MPI BEGINS CONSULTATION ON SCIENCE-BASED DEFINITION FOR MANUKA HONEY AND NEW EXPORT REQUIREMENTS

Ministry for Primary Industries

On Tuesday 11 April, the Ministry for Primary Industries (MPI) released a scientific definition to authenticate New Zealand mānuka honey, which is essential to maintaining New Zealand mānuka honey’s premium position in overseas markets.

Have your say Consultation on the proposals closes on Tuesday, 23 May 2017 at 5 pm.

The definition was part of a consultation package setting out proposed new requirements for the export of bee products. “The proposed definition and export requirements are important for the continued growth of our important export honey industry,” said Deputy Director-General, Bryan Wilson. The definition uses five attributes (four chemicals and a DNA marker) that, when present in honey at specified levels, provide clear evidence that the honey is New Zealand mānuka honey. “It is important that a cross section of people from the apiculture industry, and the public, have their say on these proposals,”Mr Wilson said.

Stakeholder workshops will be held throughout the country from 4 May to 18 May. To register for any of the workshops below, visit: www.mpi.govt.nz/honeyconsultation Location: Date: Venue: Palmerston North Thursday 4 May 10.30 am–1 pm Convention Centre 354 Main Street, Palmerston North

Claudelands Corner of Brooklyn Road and Heaphy Terrace, Hamilton

Hamilton

Friday 5 May 1 pm–3.30 pm

Expo Hall 7 Rust Avenue, Whangarei Emerald Hotel 13 Gladstone Road, Gisborne Trafalgar Centre 13 Paru Paru Road, Nelson

Whangarei

Tuesday 9 May 11 am–1.30 pm Thursday 11 May 1 pm–3.30 pm Monday 15 May 10.30 am–1 pm Wednesday 17 May 11 am–1.30 pm Thursday 18 May 1 pm–3.30 pm

Gisborne

Nelson

Sixty 6 on Peterborough Function and Events Centre Corner Peterborough & Durham Street Christchurch Central

Christchurch

The Orchard Garden 576 Dunstan Road, RD1, Alexandra

Alexandra

MPI is aiming to bring the new requirements into effect in late July 2017. For more information For a copy of the Science Summary Report, visit: www.mpi.govt.nz/manuka-honey

MĀNUKA HONEY SCIENCE DEFINITION The Ministry for Primary Industries

NEW ZEALAND BEEKEEPER, MAY 2017

TEST FOR MULTIFLORAL MĀNUKA HONEY The test for multifloral mānuka honey requires all of the five attributes. If the honey fails to meet 1 or more of the attributes, it is non-mānuka.

TEST FOR MONOFLORAL MĀNUKA HONEY The test for monofloral mānuka honey requires all of the five attributes. If the honey fails to meet 1 or more of the attributes, it is not monofloral mānuka honey – see test for multifloral mānuka honey.

TEST #1: CHEMICAL TEST

The following chemicals all need to be present:

A combination of five attributes (4 chemicals,

3-Phenyllactic acid at a level greater than or equal to 400 mg/kg

3-Phenyllactic acid at a level greater than or equal to 20 mg/kg but less than 400 mg/kg

1 DNA marker from mānuka pollen) are

2’-Methoxyacetophenone at a level greater than or equal to 1 mg/kg

required to authenticate monofloral and multifloral mānuka honey. These attributes can be identified using two laboratory tests.

2-Methoxybenzoic acid at a level greater than or equal to 1 mg/kg

4-Hydroxyphenyllactic acid at a level greater than or equal to 1 mg/kg

TEST #2: DNA TEST

DNA from mānuka pollen (*DNA level required is less than Cq 36, which is approximately 3 fg/µL)

SUMMARY OF PROPOSED REQUIREMENTS in the Draft Animal Products Notice: General Export Requirements for Bee Products for participants in the honey export chain

MARKET (doesnotapply toNZ)

BEEKEEPER

EXTRACTOR

PACKER

EXPORTER

Official Assurance countries

Honey is fit for purpose (e.g, no sugar feeding during harvest season, no AFB, no brood comb extraction) If not currently on the MPI beekeeper list, you may need to be listed in order to export

Only source beeproducts from beekeepers who are listed or are exempt from listing by the Notice

Any claims about mānuka content must comply with MPI’s mānuka honey definition Ensure other marking and representation on packages are true to label and not misleading

Comply with requirements in relation to the labelling, marking and representation of monofloral or multifloral mānuka honey Comply with requirements in relation to information to be included in export certificate requests raised for monofloral or multifloral mānuka honey consignments

Operate under a Risk Management Programme (Animal Products Act)

Check and sign each harvest declaration from a beekeeper

Mark each honey super with an MPI accepted form of identification

Honey is not adulterated after extraction

Provide transfer documentation for transfer of bee products to another operator (AP e-Cert)

Keep traceability records (apiary site, movement of hives and where necessary, supers)

Honey packed in retail packages prior to commencement of Notice with mānuka on the label may still be exported to a country that does not require an official assurance for up to 6 months after date of commencement of the Notice

Keep records for at least 4 years and make them available to MPI within 24 hours of a request: eg: harvest declarations, transfer documents, test results etc If honey is tested before the Notice comes into effect, the results can only be used for official assurances if the laboratory performing the tests was MPI-recognised for the relevant approved test method

Provide harvest declarations (for every delivery to operator who extracts honey)

Operate under a Risk Management Programme (Animal Products Act)

HAVE YOUR SAY consultation on

proposed changes closes on Tuesday, 23 May 2017 at 5pm. Visit www.mpi.govt.nz

If you are going to export honey, test samples in an MPI recognised laboratory and then check the test results meet MPI’s mānuka honey science definition

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EDUCATION AND SKILLS FOR JOBS FOCUS GROUP UNDER WAY FOCUS GROUP REPORTS: EDUCATION AND SKILLS FOR JOBS Stuart Fraser, Chair, ApiNZ Education and Skills for Jobs Focus Group

When the first meeting for this focus group was held in April, I was very appreciative of the depth of thinking that had already taken place within the industry in relation to our future training needs.

Ceremony for Apiculture Level 2 Training tauira

We have a great team on board, and will be looking to expand our contacts to ensure the industry gets the best possible platform to build upon. One of the critical issues facing our industry is the shortage of skilled people in our industry and the availability of ongoing training pathways for people. Our aim is to produce a National Standard for Training that we can all be proud to be a part of in future. I should admit here to being somewhat overly ambitious around a potential timeframe for preparation and potential delivery options, but am reconsidering this because of the wealth of experience available to call upon. The focus group will meet as frequently as possible prior to the ApiNZ conference and beyond, to ensure we get as much information together as the industry can offer. We are also looking to other industry experiences to make sure we pick the very best training options available. I wish to thank the focus group team for their open-minded and positive approach to our first of many productive meetings.

The Waikato Māori Beekeepers Charitable Trust recently held a small ceremony to acknowledge the tauira that participated in the Apiculture Level 2 Training. Chair Kyle Hunter was especially pleased with the effort made to travel great distances for the training over a period of many months. Trustee Karleen Turner Puriri provided inspiration by highlighting the range of opportunities beekeepers have to innovate, add value by getting closer to the customer and contribute to the future of the industry. The Trust committee thanked the tauira for their dedication. A special thank you was also made in recognition of the mahi contributed by the team at the Waikato-Tainui Nursery and support from Te Puni Kokiri, Primary ITO, Waikato Raupatu Lands Trust, Coast to Coast Queens, Whaimanawa and head trainer Warren Yorston. The success of the training that targeted Māori land owners has been the establishment of whanau enterprises focused on working broadly across apiculture.

The Waikato Maori Beekeepers Charitable Trust, with Minister of Maori Development Te Ururoa Flavell. Sitting, left to right: The Hon Te Ururoa Flavell, Matua Taki Turner. Standing, left to right: Michelle Paki, Bob Pene, Uncle Barm Turner, Avie Tuteao, Aunty Tilly Turner, Kyle Hunter, Warren Yorsten, Karleen Turner Puriri, Tammy Tauroa, Lee Tane.

Karleen Turner Puriri (Trustee), Aunty Tilly Turner (Nursery Manager), Michelle Paki (Trustee), Kyle Hunter (Trustee), Warren Yorsten (Trainer), Avie Tuteao (Trustee), Amanda Pu (Trustee) Lee Tane (Waikato Raupatu River Trust). Photo supplied by Karleen Turner Puriri.

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MPI/BIOSECURITY

MYRTLE RUST FOUND ON RAOUL ISLAND TREES

Media release from the Ministry for Primary Industries, 4 April 2017

The Ministry for Primary Industries (MPI) and the Department of Conservation (DOC) are working together to address a confirmed find of the fungal plant disease myrtle rust on Kermadec pōhutukawa trees on Raoul Island.

Myrtle rust (Austropuccinia psidii), also known as guava rust and eucalyptus rust, is a fungal infection that could have serious impacts on a wide range of plants in the myrtle family. If it were to enter mainland New Zealand, it could affect iconic New Zealand plants pōhutukawa, kānuka, mānuka and rātā, as well as commercially-grown species such as eucalyptus, guava and feijoa. MPI’s Director Readiness and Response, Geoff Gwyn, says myrtle rust spores can carry long distances on the wind, however, the Raoul Island location is very remote from mainland New Zealand. “It’s over one thousand kilometres to the northeast of Northland and access to the island is strictly controlled and only by permit. Those visiting Raoul Island are mainly scientists and maintenance people, mostly working for DOC. “DOC staff discovered the small number of affected trees and safely transported samples back to New Zealand for testing, following strict biosecurity protocols,”Mr Gwyn says. “Our focus right now is to do what we can to protect the unique Raoul Island ecosystem from this disease, and to prevent the further spread of the fungus to mainland New Zealand. “We’re working closely with DOC, iwi and local authorities on a range of options and will do everything feasible. We will be taking the advice of a number of technical experts in this field, including in Australia where they have experience in dealing with myrtle rust.” Mr Gwyn says strict precautions are in place to make sure people, equipment and samples being brought back to mainland New Zealand pose no risk of transmitting infection. New Zealand already has stringent biosecurity measures to protect against myrtle rust introduction, including a complete ban on imports of cut flowers and foliage from myrtle species from New South Wales, Queensland

Myrtle rust (Austropuccinia psidii) on leaves of the Kermadec pohutukawa on Raoul Island.

and Victoria. Myrtle rust is well established along the eastern seaboard of Australia and in New Caledonia. Anyone believing they have seen myrtle rust on plants in New Zealand should call MPI on 0800 80 99 66. Do not attempt to collect samples as this may aid in the spread of the disease. Reference Ministry for Primary Industries. Serious fungal plant disease found on Raoul Island trees. Media release, April 4, 2017. Retrieved April 4, 2017, from http://mpi. govt.nz/news-and-resources/media- releases/serious-fungal-plant-disease- found-on-raoul-island-trees/

A close-up view. Photos courtesy of the Ministry for Primary Industries.

continued... continued...

NEW ZEALAND BEEKEEPER, MAY 2017

PHOTO ESSAY

FLOODING AT TE AROHA, WAIKATO Jo Telfar took these photos of her beehives and other land around Te Aroha in the aftermath of cyclones Debbie and Cook, which delivered a one–two punch in mid-April.

Further information about myrtle rust • Look out for this distinctive yellow/ orange fungus on leaves and young plant stems. Report it to MPI on 0800 80 99 66. • Carefully note the location. Photograph the rust AND the affected plant/leaves. As myrtle rust only affects certain plants, we can rule it out by seeing the plant. • DO NOT TOUCH the plant or rust. Do not take a sample. Touching it can spread it. • Call through your sighting to MPI on 0800 80 99 66. • bright yellow/orange powdery patches on leaves; • brown/grey rust pustules (older spores) can appear on older lesions; • leaves may become buckled or twisted and die off. For more information, go to http:// www.mpi.govt.nz/protection-and- response/finding-and-reporting- pests-and-diseases/pest-and-disease- search?article=1484 • Symptoms to look out for are:

Jo’s son Joshua Martin out helping his mum with the bees, which he often does. Jo said, “You can see how close the floodwaters came to our hives (that were closely watched)”.

Below: Jo took this photo on 17 April, after Cyclone Cook blasted Waikato for a second time, adding to the flooding problems. Jo remarked, “We captured only a couple more [photos] this morning as it was bright sunshine and as soon as we got to this site, in rolled the black clouds and it pelted down! The floodwater you can see is usually all pasture. The Waihou River runs straight through this farm and of course due to the cyclone, flooded a large part of Te Aroha and surrounding farms”.

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WHAT WE HAVE LEARNED ABOUT GIANT WILLOW APHID HONEYDEW HONEY RESEARCH Steve Howse, Analytica Laboratories The giant willow aphid arrived in New Zealand in the last five to 10 years, and produces a honeydew collected by bees which they turn into honey. This honey often contains crystals of the complex sugar melezitose, which makes it hard to extract using conventional techniques, and is less useful for bees to use as a source of food for the hive. Using an alternative extraction technique, there is potential for it to be a unique honey that rivals European forest honeys.

The giant willow aphid (GWA) is an unwelcome import to New Zealand that appears to be here to stay. Articles in The New Zealand BeeKeeper since 2015, often by or involving Dr John McLean from Gisborne, have described the impact that the GWA is having on hives (McLean, 2015; Foster, 2016, 2017). Judging by the buzz of activity in the willows growing on our property in the central Waikato, this season will be no different! At Analytica we have been involved in testing honey that has been made by bees collecting GWA honeydew. While we have not carried out any large-scale studies on this matter, we thought it would be useful to share some observations about what we have seen, and heard. By sharing, we hope we can contribute to the industry’s learning to best manage the impact of this insect pest. As with other articles on this subject, I again acknowledge the valuable input provided when writing this by Dr John McLean. We are fortunate to have the benefit of John’s enthusiasm and enquiring mind at work for the benefit of our industry in New Zealand. John did a presentation on the topic at the 2016 Apiculture Conference on Tuesday, 21 June 2016, which can be accessed via https:// apinz.org.nz/news/conference-videos/ Figure 1. Colony of giant willow aphids with several winged adults collected March 23, 2015. Photo: Dr John McLean.

Figure 2. A honey bee and bumble bee feeding on honey dew from the giant willow aphid at Te Rahu nursery. Photo: Steve Pawson, SCION Research.

Giant willow aphids produce honeydew by feeding on willow trees The giant willow aphid (Tuberolachnus salignus) is an insect that lives by sucking the sap from willow (and poplar) trees. In the same way that a mosquito sucks blood from a person, or a passion vine hopper sucks sap from a tutu plant, the aphids effectively insert a feeding tube into the stem of the willow tree and start gulping up the sugary sap flowing in there. Plants naturally have sugars in their sap (along with amino acids and other things useful for plant growth). In the case of willows, some old research (Mittler, 1958) states that the sap contains sugar in the form of sucrose. In the process of digesting the sap, the aphids use some of the sugar for their own growth, and convert some into a more complex sugar

called melezitose as a way of managing osmotic pressure in their digestive tract. The aphids excrete the digested sap as a sugary honeydew, which is very attractive for hungry bees and wasps (especially in late summer and autumn when other sources of feed are getting scarce). The melezitose is a key thing in this process— while simple sugars (glucose, fructose, and sucrose) are a good source of nutrition for bees, melezitose is, unfortunately, indigestible for them. Features of honey made from giant willow aphid honeydew Without going into a lot of detail, following are some observations that honey producers have made to us about honey made from GWA honeydew, or that we have observed ourselves at Analytica. Some of them need

continued...

NEW ZEALAND BEEKEEPER, MAY 2017

Implications of having giant aphid honey willow The beekeeper and extractor are affected most by this honey. • Melezitose is not digestible for bees. Therefore, any honey they make from GWA honeydew will be of less use for feeding the hive, with energy also being needed to clean out crystals from cells. Perhaps 30% of the honey in heavily crystallised GWA honeydew honey will be unusable by bees. • It is disappointing for a beekeeper to find that the weight of their honey boxes does not translate into the amount of honey they expect in the drum, if there are a lot of melezitose crystals in the comb. • Extractors use a lot of time and energy keeping their filters clean when dealing with frames containing the honey. If the taste and smell of the honey is not what customers are expecting, it could damage the brand of the seller. Of course, people have a wide variety of tastes, and what may be unpleasant for one person could be something another person loves. Just talk to people from the USA or Europe about Vegemite or Marmite! If there are melezitose crystals in drums of honey that are being traded, the buyer will end up with some of the weight of the drum being unusable. A simple way of checking for this is sending a sample of the liquid honey from a drum to a laboratory for melezitose testing. If the results show that there is more than 14% of melezitose in the honey, then there is a high risk of having crystals in the honey, which will affect the overall value of the drum. An alternative test is for salicylic acid, which is a natural component of willow sap. According to Dr John McLean, if you have more than 15 mg/kg of salicylic acid in honey, then you are likely to have melezitose crystals to deal with. High yeast counts in the honey can increase the risk of fermentation, and are considered to be a sign of the honey being unsanitary. You can ask a microbiology lab to carry out a Yeast and Mould Test. The test is relatively inexpensive and will give you useful information. A result of > 200 CFU/gram would result in the honey being considered unfit for human consumption in some countries, and of course a result of close to zero is ideal.

some more investigation, but it will be helpful to get more feedback from people in the industry to confirm or deny or add more detail. 1. In the comb GWA honey is quite crystallised, making it hard to extract using conventional extraction techniques, and crystallises easily. As I understand it, people running extraction plants are getting very good at identifying frames of GWA honey after frustrating days changing filters in recent seasons. 2. GWA honey crystals don’t melt out with gentle warming like other honeys. This is again due to the melezitose, which will form crystals if there is more than 14% of it in the honey. I have heard of one extreme example where a drum of honey had 100 prone to clogging up extraction filters because the melezitose in the honey

kg of crystals in the bottom of it, which the owner could not liquefy using any normal technique like heating or stirring. 3. The honey has a distinct smell and taste, which many Kiwi beekeepers don’t seem to like. However, Dr John McLean has provided samples of GWA honeydew honey to European honey tasting experts who have enjoyed its flavour, so it is very much a case of ‘horses for courses’. 4. Yeast counts in GWA honey may be much higher than would normally be expected, leading to risks of fermentation and perhaps product rejection by customers. The honeydew being collected by the bees is sitting on willow leaves and out in the open—a great environment for natural yeasts and moulds to grow in.

Figure 3. Residual melezitose sugar in ‘extracted’ wet. Photo: Dr John McLean.

NEW ZEALAND BEEKEEPER, MAY 2017

AN ALTERNATIVE APPROACH TO EXTRACTING GWA HONEYDEW HONEY Dr John McLean

I extract small samples of GWA honeydew honey at home by scraping the capped honey from the frames, heating it to 72°C in a stainless-steel bowl that is sitting in a water bath, and allowing it to settle overnight. The following morning, the wax with bee pieces, etc., can be lifted off and the honeydew honey is easily decanted without any need to filter. The melezitose crystals stay as a gloopy mass in the bottom of the bowl.

The challenge is how to develop a higher volume extraction method which follows these principles. Professional Italian honey tasters rated GWA honeydew honey extracted in this way as better tasting than manuka honey! Recently a Swiss gentleman I spoke with expressed his preference for “forest honey” such as this. Another famous example is honey which is prepared from the honeydew of aphids feeding on conifers in the German Black Forest.

Figure 5

Extraction of willow honeydew honey

Water bath 75 o C

References Foster, B. (2016, March). Willow aphid trial in Bay of Plenty. The New Zealand BeeKeeper, 24 (2), 14–15. Foster, B. (2016, October). Combatting the giant willow aphid threat. The New Zealand BeeKeeper, 2 4(9), 19. Foster, B. (2017, February). Giant willow aphid research kicks off. T he New Zealand BeeKeeper, 25 (1), 9. Mittler, T. E. (1958). Studies on the feeding and nutrition of Tuberolachnus salignus (Gmelin) (Homoptera, Aphididae). II. The nitrogen and sugar composition of ingested phloem sap and excreted honeydew. Journal of Experimental Biology, 35 , 74–84. McLean, J. (2015, August). Have you seen willow honeydew honey this season? The New Zealand BeeKeeper, 23( 7), 6–7. McLean, J. (2015, September). [Letter to the Editor]. Melezitose sugar. The New Zealand BeeKeeper, 23 (8), 11. FIgure 4. Colony of giant willow aphid on a willow branch collected May 30, 2015. Note the very large adult aphid with the black tubercle on her back near the middle of the colony. No males are known for this species and the adults give birth to live young, a process termed parthenogenesis. Caption and photo: Dr John McLean.

Cool overnight

Top view and underside view of a hive tool scraping of willow honeydew honey from a comb.

Lift off wax and debris Strain

Honey

debris melezitose

Figure 6

Waikato Honeydew Honey 2016 Prepared by decanting, no filtering.

capping

willow honeydew honey

melezitose

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VARROA TREATMENTS: MODE OF ACTION AND RESISTANCE PEST AND DISEASE CONTROL Dr Pablo German, Chief Technical Officer, Pheromite E-mail: pablo.german@pheromite.com

How do the different varroa treatments kill the mites? Why do they kill the mites and do not kill the bees? Can mites become resistant to a particular treatment? Do we care about answering all these questions?

In the presence of tau-fluvalinate and flumethrin, only mites with specific mutations in the voltage-gated sodium channel are able to survive and continue reproducing. The relatively high likelihood of a single mutation in a single gene to occur, explains why resistance to tau-fluvalinate and flumethrin has been broadly reported around the world. In fact, several single mutations in the voltage-gated sodium channel have been identified that produce tau-fluvalinate- and flumethrin-resistant varroa mites. Amitraz The synthetic chemical widely used for treating varroa mites is the contact pesticide amitraz (Apivar®). The evidence of the mode of action of amitraz on varroa mites comes from insects and other mites and points to effects on octopamine receptors. The role of octopamine in insects and mites is similar to the role of noradrenaline in humans, which is to trigger the fight-or-flight response. When you are startled by something, your body releases noradrenaline, which binds to the noradrenaline receptor present in tissues and organs throughout your body. Your heart pumps faster, your muscles release quick sources of energy, and you get ready to fight or flee. A similar stress response occurs in insects and mites when octopamine is released, which binds to the octopamine receptors. Amitraz seems to act by binding to the octopamine receptor(s), which leads to an acute stress response with different effects in insects and mites. Figure 3. Amitraz.

Most beekeepers do care for several reasons. First, we have the natural curiosity of wanting to understand how things work. Second, the more we know about our varroa mite enemy and the weapons we use, the better we will be able to fight against it. Third, we want to understand what secondary effects the treatments may have on the bees. Finally, the mode of action can give clues about the ability of the mites to develop resistance against the treatments. In spite of the importance of this topic, there are no good summaries on how different treatments affect the mites. There are also unsupported opinions circulating on the Internet. In this article, I review the scientific literature and summarise the mode of action of different varroa treatments as the knowledge currently stands. Some of the treatments act as the chemicals are absorbed within the body of the mite, others have direct physical effects upon contact, and others stimulate defensive behaviours from the bees. Tau-fluvalinate/flumethrin The synthetic chemicals tau-fluvalinate and flumethrin (Apistan® and Bayvarol®) belong to the family of pyrethroids that includes a large number of insecticides used domestically and in agriculture. Figure 1. Tau-fluvalinate.

Figure 2. Flumethrin.

neurons. The inability of the channel to close and reset the neuron to the resting state leads to paralysis and death. Imagine if all your muscles contracted at the same time: you wouldn’t be able to move and breathe. The reason why tau-fluvalinate and flumethrin are such powerful weapons against varroa is that these compounds have a high affinity for the varroa mite voltage-gated sodium channel. Interestingly, a recent study reported that tau-fluvalinate has even higher affinity for the honey bee voltage-gated sodium channel. The established safety profile of flumethrin in bees suggests that the bees have detoxification mechanisms that prevent the harmful effects. The high affinity for one single target makes tau-fluvalinate and flumethrin very effective at killing the mite, while at the same time being relatively safe for humans. Unfortunately, this high affinity for one single target also enables mites to become resistant to tau-fluvalinate and flumethrin with a single DNA mutation in the voltage-gated sodium channel. Random mutations occur all the time, so one single DNA mutation in one gene is an event likely to occur when thousands of mites are breeding in one single beehive.

They work by producing an over-excitation of the nervous system of the mite. In particular, they bind to the voltage-gated sodium channel, present on the membrane of

continued...

NEW ZEALAND BEEKEEPER, MAY 2017

What happens when mitochondria in the mite are disrupted? Mitochondria are present within cells and carry out cellular respiration and energy production. When the mitochondria are disrupted, the cells cannot function. This probably leads to neurotoxic effects by disrupting the mitochondria in the neurons and inhibition of respiration. Formic acid seems to cause mitochondria disruption by the physico-chemical effects of low pH. It has been suggested that the bees have higher metabolic and buffering capacity against the acid, which explains why formic acid affects mites more than bees. This mode of action suggests that resistance is not likely to occur as several changes would be needed in the mite. No mite resistance to formic acid has been reported. Oxalic acid Oxalic acid is the other common organic acid. As opposed to formic acid that kills mites with the acid vapours, the main way in which oxalic acid kills mites seems to be by direct contact. Figure 6. Oxalic acid. There were some reports that oxalic acid may damage the mouthparts of the mite. However, there is no scientific evidence for this and the origin of this concept seems to be a manipulated picture published on the Internet. What we do know is that oxalic acid needs to be in direct contact with the mite and is distributed around the hive via bee-to- bee contact. Given that oxalic acid has been shown to affect mitochondria in mammals and that mitochondria are sensitive to acids, it is possible that oxalic acid also affects the varroa mite by disrupting or affecting mitochondrial function. In any case, a physico-chemical mode of action would explain why there have been no reports of mites resistant to oxalic acid. Sugar dusting There is evidence that sugar dusting with powdered sugar helps increase mite fall and reduce mite numbers. Sugar dusting seems to act in two ways. First, it affects the mite’s

Most beekeepers have noticed that amitraz is slower at killing mites than flumethrin, for example. The reason for this seems to be that by causing this stress response, the mite does not die immediately but its behaviour is completely altered, which leads to death later on. Amitraz is said to act by sub-lethal effects rather than by lethal effects. Humans, and in fact all vertebrates, do not have octopamine receptors, which is the reason why amitraz is relatively safe for humans. The relatively slow and low onset of varroa mite resistance to amitraz—when compared to resistance to flumethrin for example— seems to indicate that amitraz acts on more targets than just one type of octopamine receptor. Indeed, resistance to amitraz has been reported in fewer cases than the previous two miticides, and studies have shown that the level of resistance is lower as well (the dose of amitraz needed to kill amitraz-resistant mites is not that much higher). In fact, amitraz is still the most effective miticide used in the USA, despite resistance having been reported two decades ago. This seems to point to the fact that one single mutation in one gene is not enough to provide resistance. Although point mutations in amitraz-resistant organisms have been identified, evidence from a cattle tick indicates that resistance to amitraz occurs both by mutations in the octopamine receptor and enhanced metabolism in getting rid of amitraz. In spite of the lower resistance to amitraz by the varroa mite, alternating amitraz with other treatments is still necessary. Thymol So far we have only talked about synthetic chemicals. Other chemicals present in nature are known as ‘organic’. Plants, in particular, constantly have to evolve ways to survive against pests. Hence, it is not surprising that several chemicals from plants have insecticide and miticide effects. In contrast with synthetic chemicals that are generally designed against one particular target, plants have to fight against many different pests at the same time. This makes their chemicals more broad spectrum, usually affecting several targets. Essential oils have been shown to have insecticidal effects and thymol, derived from thyme, is most commonly used against the varroa mite. As with previous treatments, most of what we know about how thymol works comes from evidence on insects. Similar to amitraz, some essential oils also appear to have neurotoxic effects by binding and affecting the function of octopamine receptors. In addition, thymol binds to

Figure 4. Thymol.

tyramine receptors, which are related to the octopamine receptors but whose function is not entirely understood. There is further evidence that thymol affects the function of gamma-aminobutyric acid (GABA) receptors in insects, which are also important for nerve signal transmission. The presence of multiple targets for thymol makes it more difficult for resistance to occur. In fact, there are no published reports of mite resistance to thymol. This does not mean that resistance to thymol is impossible. One way in which resistance could arise would be by improvement in the detoxification system of the mite. Therefore, it is still best practice to alternate thymol with other treatments. Formic acid Other popular miticides used against varroa are organic acids. Formic acid is a volatile acid that works in the hive as a fumigant.

Figure 5. Formic acid.

Initially it was observed that formic acid affects respiration in the mite and this was linked to previous studies suggesting that formic acid inhibits cytochrome c and the electron transport chain in the mitochondria. In addition, formic acid was also suggested to have neurotoxic effects in flies. Later studies seem to suggest that formic acid kills insects, and probably varroa mites, by disrupting the mitochondria in the cells.

NEW ZEALAND BEEKEEPER, MAY 2017

ability to cling to bees and they fall off. Second, it stimulates bees grooming themselves and grooming each other, which also produces mites to fall off. Given the physical mode of action, resistance to sugar dusting is not possible. However, sugar dusting has been said to have a small effect in reducing mite levels and may only be useful as a complementary method together with other methods. Food-grade mineral oil There is very little literature on the use of food-grade mineral oil (FGMO) for varroa control. However, some beekeepers like to use it either by fogging with thermal insect foggers or with cords. FGMO only affects phoretic mites (mites on bees) and it needs to be applied often to have any effect. Regarding the mode of action, some comments on the Internet point to the oil blocking the pores in the mite’s cuticle and preventing gas exchange, which affects breathing. The cuticle of the mite seems to make it more susceptible than bees. If this physical mode of action is correct, resistance is very unlikely. It is possible that the oil also stimulates bee grooming behaviour.

The synthetic chemicals are absorbed by the mite and tend to affect one single protein target, such as the voltage-gated sodium channel (flumethrin and fluvalinate) and octopamine receptors (amitraz). This specificity on single targets makes it highly likely that the mites will develop resistance by mutations in those targets, as has indeed been reported for all of them. In addition, mites can also develop resistance with detoxification enzymes that degrade or get rid of these chemicals from the body. The organic chemicals act by absorption or direct contact and seem to act by physico- chemical effects on more than one target, making them less specific against varroa mites. This is a logical consequence of the fact that these chemicals are synthesized by plants to fight against different types of insects and pests and not against mites in particular. Indeed, thymol seems to act by affecting octopamine, tyramine, and GABA receptors, formic acid disrupts the mitochondria in cells, perhaps as a consequence of low pH, and oxalic acid may also act by affecting mitochondrial function. The action on more than one target or by physico-chemical effects that disrupt cell structures makes resistance to these treatments less likely. In fact, there are no reports of resistance to these treatments. However, alternation with other treatments is still recommended. Finally, the less-popular icing sugar and food- grade mineral oil treatments seem to affect the mite by physical effect due to the direct contact and by stimulating bee grooming behaviours. This means that resistance to these treatments is very unlikely to arise.

A gorgeous frame of honey. Photo: Jo Telfar.

Conclusion The mode of action of different varroa

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treatments has not been studied in detail for most treatments. However, we can still get an idea from studies in insects and other mite species. Different treatments have different modes of action: either chemically after being absorbed, physically by direct contact, or by stimulating defensive behaviours from the bees.

Treatment

Mode of Action

Resistance?

Flumethrin/fluvalinate Voltage-gated sodium channel

Yes

Amitraz

Octopamine receptor

Yes

Thymol

Octopaminergic system, tyramine and GABA receptors

Less likely

Formic acid

Mitochondrial disruption, neurotoxic

Less likely

Oxalic acid

Mitochondrial function

Less likely

Sugar dusting

Grooming, affects ability of mites to hold on to bees

Not likely

Food-grade mineral oil

Suffocation, grooming

Not likely

Table 1. Various treatments, their mode of action and likelihood of varroa resistance.

References Complete article with references is available on request from the author: pablo.german@pheromite.com

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