Surveillance and diagnostics key to protect bee industry

  • Surveillance and diagnostics key to protect bee industry image

With over 29,000 registered beekeepers who own approximately 668,000 hives, keeping Australia’s honey bee population healthy is no mean feat.

Australia’s geographic location, a world-class biosecurity system and programs such as the National Bee Pest Surveillance Program (NBPSP) protect the industry from high priority pests that devastate honey bee industries overseas.

The NBPSP is a large industry-government partnership jointly funded by Hort Innovation, the Australian Honey Bee Industry Council (AHBIC), Grain Producers Australia (GPA), the Australian Government and State and Territory governments.

The program currently targets 13 pests that range from giant honeybees at 17-20 mm long to tracheal mites which are less than 0.2 mm in size, and viruses which cause significant disease in colonies.

The NBPSP uses a range of tools and tests to detect these pests.

A lot of surveillance activities are undertaken in the field at ports of high risk concern for the entry of these target pests.

“Several different types of samples are collected and sent to a specific laboratory and highly-trained individuals who inspect the samples or expose the samples to further tests, to detect exotic pests as soon as possible,” said Dr Jenny Shanks, Plant Health Australia’s Manager, Bee Biosecurity.

The types of tools used in diagnostics vary. Beekeepers can do a physical inspection for pests by looking at hive frames or undertaking sugar shakes or alcohol washes. Laboratories have a wider range of diagnostic tools such as microscopes to inspect bees, sticky mats for mites, dissection to remove the trachea of individual bees, and molecular tests for detecting viruses. These tools assist with Varroa species identification and to genetically confirm exotic bee species.

Interestingly, birds can also assist in diagnostics. The presence or absence of pest bees in regurgitated pellets, can be inspected in a laboratory for the presence of bee wings.

“The wings are then inspected for venation arrangement, as wing veins are different between Asian honeybees and European honeybees,” said Dr Shanks.

Government-based laboratories are charged with the inspection of sticky mats. These traps are specifically designed pieces of cardboard with a sticky surface based on the floor of sentinel hives. The hives are then treated with an acaricide, which is a chemical used to target exotic mites only. If there are mites in the hives, once exposed to the chemicals, they fall through the hive and land on the sticky surface of the mat, and become trapped. The mats are removed and inspected under a microscope for the presence or absence confirmation of mites like Tropilaelaps and Varroa mites.

“25,147 sticky mats were inspected by trained Australian laboratories between 2016-2021, and all samples returned negative results for Deformed wing virus (DWV), Acute bee paralysis virus (APBV), and Slow bee paralysis virus (SBPV), ” said Dr Shanks. “

Specialist entomologists such as Alberto Guanilo from Bugs for Bugs Ltd. dissected at least 25,000 adult honeybees between 2016 and 2021, removing the trachea of the bee and inspecting for the presence or absence of a ‘tracheal mite’. This method requires the careful and precision dissection of the trachea from the bee under a microscope. The samples of bees were collected from hives, swarms captured in catchboxes and around port areas, and during floral sweep netting activities by government biosecurity officers. In Tasmania over 4,000 bees have been inspected for tracheal mites.

Dr John Roberts from the CSIRO has developed an exotic virus assay, used on samples of bees collected from hives to inform the presence or absences of harmful bee viruses not currently in Australia. Some of these viruses include Deformed Wing Virus (DWV), Acute Bee Paralysis Virus (ABPV), and Slow Bee Paralysis Virus (SBPV). Between 2019 and 2021, 600 samples of adult bees were provided to the CSIRO lab for testing of these three key bee viruses. All samples over the 5-years have returned negative results for DWV, ABPV, SBPV.

The NBPSP stakeholders and managers are continuously exploring new innovative diagnostic tools to improve detection sensitives and laboratory capacity and efficiency, such as trialling molecular tests for detection of tracheal mite, or the use of eDNA to detect even more information of target pests.