Bee Keeping Post Varroa

September 2007
Until the arrival of the varroa mite, beekeeping had a low but important profile in New Zealand agriculture. Seven years on from the mites arrival Wellington beekeeper Frank Lindsay reflects on its impact and the changing face of the industry.

Frank is a professional beekeeper running 400 hives in the Wellington region.

He supplies bulk honey to the honey packers. He is based out of suburban Wellington. Hes been in the industry for 38 years.

Varroa

It is thought the varroa mite was probably in New Zealand for around two years before it was detected in Auckland in April 2000, but it is not known how it arrived here. It was first found near a shipping container terminal in Onehunga. Live bees usually spread varroa, but there have been no legal imports of live honey bees into New Zealand for at least 40 years. Varroa could have arrived with an illegal introduction of queen bees, or in a bee colony or swarm that established on or in a shipping container.

NZ biosecurity agencies tried to control the spread of the mite by setting up a movement control area across the central north island. This was breached at some point. Frank believes varroa got to Wellington via log brought down from up North for processing in a Wellington timber mill. A hive was found in the log and is thought to have been infected with the mite.

Varroa bee mite spread in New Zealand

Varroa is widely distributed throughout the entire North Island, including many offshore islands in the Hauraki Gulf, and was detected in Nelson beehives in the South Island in June 2006. There is a varroa controlled area now around the Nelson Blenheim area, and efforts are being made to eradicate varroa from the upper South Island but many industry insiders believe that is impractical and unlikely.

Impact on New Zealands bee industry

Varroa is impacting on New Zealand agriculture in two ways:

The varroa bee mite is killing and or reducing the number of bees in managed hives as well as feral or wild colonies. This is having a measurable impact on the beekeeping industry, but it is also potentially devastating for crop pollination and pollination of pasture legumes. It is estimated varroa is costing beekeepers $30 to $50 a hive in control costs alone. Over 2000 beekeepers have given up keeping beehives since varroa arrived in 2000 and all commercial beekeepers in the North Island have suffered hive losses and have had to change their management practices.

Impact on pollination

The apicultural industrys major contribution to New Zealands economy is the pollination of plants, which is worth many times the value of its honey, other hive products and live bee trade. It is estimated that one third of the food we eat relies on honey bees for pollination, and the area of crops reliant on bees for pollination is increasing. If the varroa bee mite becomes established in the South Island this will further compound the problem.

Assessments of the economic impact of varroa on South Island agriculture alone have shown the potential economic impact of establishment of varroa in the South Island to be between $198 and $433 million.

Along with the cost of treating hives for varroa Frank says the industry is also continuing to learn about managing hives with varroa. He says the demise of the wild bee population means theres more nectar available and bees are more inclined to swarm more often. These bees will ultimately die off or return to the hive at some point carrying varroa with them.

Dead Bees Dont pollinate

There''s an ongoing battle for beekeepers with American Foul Brood and what appears to be a new challenge, which is appearing overseas and starting to be seen here, called CCD - which stands for Colony Collapse Disorder.

Theres is ongoing research on what is causing otherwise healthy hives to die but many are now starting to draw the conclusion that it is connected to the use of insecticides on crops.

Tiny amounts of the insecticides used on crops tend to end up in the nectar and pollens. These might not be of sufficient amounts to kill the bees but the poisons can accumulate in the wax and end up having an impact of the next generation of brood stock.

Frank says a common insecticide being used in New Zealand is starting to be linked to hive losses. There have been incidences of bee losses in kiwifruit two seasons ago with direct links to a product that has now been withdrawn from the market.

The reasons that this is starting to appear now are numerous. It may be to do with the misuse of treatments, bees already under stress from varroa, and the large amount of shifting of hives to get them onto various crops or pollination work.