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NEW ZEALAND BEEKEEPER, JUNE 2017
research around the world that could have helped beekeepers. They said they were aware of at least two German universities already researching the use of RNAi to control varroa. Bee testing and risk assessment in ecotoxicology I next met with Dr Maria Teresa Almanza. Her group is part of the Environmental Safety work that is conducted on site. Dr Almanza has nine staff and a dedicated lab conducting bee testing for Tier 1 studies. Her team is also doing work on testing bumble bees (bombus terrestris) and solitary bees using the red mason bee (Megachilidae osmia spp). She describes bees as “little biological black boxes” that are just beginning to teach us how they function. Currently the team is also doing a lot of work renewing pesticide registrations for the European Food Safety Agency, which means ecotoxicity testing of honey bees. Dr Almanza also said that Bayer was now testing the tank mixture as per the label recommendation, which I welcomed as it includes spray tank adjuvants. We toured Dr Almanza’s laboratory where they showed me their present methods for complying with OECD Guidelines. We then discussed the limitations they had experienced. They showed me their testing methods for the OECD 213 Acute oral and OECD 214 Dermal Test and the brood test for honey bees.
• bumble bees: larvae testing is not possible as the bumble bee caps the larvae cell, opens it for feeding and then recaps it. Note that bumble bees always lay their eggs only in clean new wax cells. Varroa control Bayer has its varroa control products business in the Bayer Animal Health division. I met Dr Klemens Krieger, Head of Special Projects, Bee Health. Bayer is looking for new acaricides suitable to control varroa, but none have been discovered to date. A key issue is that all treatments have some adverse side effects, and at low rates to protect bees they do lose some effectiveness. The other issue is that the worldwide market for varroa control products is very small when compared with other animal health markets, so it is a challenge to get resources. Dr Krieger confirmed that later in 2017, Bayer is going to release the Bayer PolyVar Yellow 275 mg beehive gate i . This is an acaricide embedded in a polymer entrance gate, which the bees pass through on entering the hive and are coated with flumethrin to control adult varroa. Results to date have shown excellent varroa control for periods up to five months. Dr Krieger does not know at what stage market release will occur in New Zealand, but he expects it will happen. Bayer had hoped to release three beehive gate products, one containing flumethrin and one of which was to contain coumaphos in order for beekeepers to have three products to manage resistance to any one chemical. Unfortunately, they have some challenges continued...
We discussed the limitations of the dermal test, as it does not represent actual pesticide spraying and is of academic interest only. The OECD field test 75 Honey Bee (Apis mellifera L.) Brood Test under semi-field conditions in a tunnel house (see photo on previous page) has proven to be very reliable based on Bayer’s global experience. Bayer had been experiencing problems with the OECD guidelines for chronic pesticide testing of brood. They were experiencing high larvae death rates at day 8 with no explanation, and the test was not providing consistent results when subject to multiple testing using the same materials. Bayer expressed concerns about the method and test design, and feels that the fragility of the egg and larvae are contributing to their problems. They will continue the testing but expect major changes for the method. Their goal is to develop a robust modelling approach to simulate hive, crop and environment. They are struggling with Tier 3 studies as it is impossible to reduce severe disruption of the hive. As for the other pollinators, the bee tests are not often suitable. Examples include: • red mason bee: acute oral testing is not possible, as the bee can choose not to feed for some days. Larvae testing is not possible, as the bee seals the egg with pollen and nectar sufficient for larvae growth and development and never
reopens the cell until the bee hatches. Also, the red mason bee lays cells on top of each other: the first laid is the last to hatch
Bayer’s Chief Beekeeper Hivemaster Peter Trodtfeld with the old apiary house at the Hofchen Research Farm. The apiary house is no longer used.
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