12 April 2000

MAF field teams begin beehive inspections for Varroa mite

Five field teams of apiarists led by Ministry of Agriculture and Forestry authorised personnel were out in South Auckland today inspecting beehives for the honey bee mite, Varroa jacobsoni.

A field operations headquarters was made operational. Policies have been developed to ensure that such a large-scale survey proceeds in a coordinated manner, with high priority tasks attended to at the earliest opportunity.

The survey got underway within the proposed controlled area, which was put in place last night by the Ministry, after the Varroa mite’s presence was found on three beehives on a South Auckland property on Tuesday. Three other inspected properties also showed signs of infestation.

All the suspected infected premises were non-commercial operations with small numbers of hives, totalling 14, within a 10-km distance from each other. Eight of these hives were dead, with others showing low populations and other typical symptoms of Varroa mite infestation. Two hives on the first property identified were immediately destroyed by the owner.

The pattern on these properties suggests that natural dispersal through bee movements (abandoning and robbing of crashed hives) is the likely means of dissemination. Tracing forwards and backwards from these premises, in particular identifying high-risk movements such as bees, hives and equipment, is taking place.

MAF and the National Beekeepers Association (NBA) are working together to determine how far the mite has spread and options for control. The survey is to be undertaken within the controlled area. High priority has been assigned to visiting and inspecting beehives in the area immediately surrounding the infected premises, in particular commercial premises; the outer perimeter of the controlled area; and high risk traces from infected premises. Reports in response to a MAF request that beekeepers nationally inspect hives looking for signs of Varroa infestation will also be investigated.

At this stage it is unknown how the mite arrived in New Zealand. The evidence suggests it may have been present and undetected for up to five years. Spread is commonly by live bees, and there have been no live bee imports permitted into New Zealand for at least 40 years to protect our bee health status. The mite spreads by natural means very slowly, at a rate of 5 km a year. When first affected, hives have low numbers of mites that are not easily seen. Numbers build up over several years until the hive dies.

Trade implications

Exports of live bees out of New Zealand have stopped, even though some of our major markets of bee products (Canada, Korea and Europe) have Varroa present. Because of this, bee exports are not expected to be halted for long. New Zealand has a large live bee export market with 17, 500 packages of 1kg of bees exported to Canada and Europe in 1999. All bee exports usually go through Auckland International Airport and special requirements, which met OIE specifications will be required, for the export certification of the products.

Once MAF is aware of how far the mite has spread within the controlled area, the Ministry will be looking to reopen exports.

Notice of Movement Controls

MAF is establishing a controlled area under the Biosecurity Act 1993, in order to impose movement controls on things that could cause the spread of the mite.

The things that MAF is controlling the movement of are:

Honey bees (meaning Apis mellifera), including package bees, queen bees, and the whole or any part of any dead honey bee.

Beehives (meaning any thing that is being or has been used for the keeping of honey bees), including nucleus beehives.

Any part of any beehive, including frames, boxes, lids and bases, and supers of honey.

Used beekeeping equipment (meaning any thing that is being or has been used in connection with beekeeping).

There are two levels of control that will apply.

The highest level of control applies to Rodney District, North Shore City, Waitakere City, Auckland City, Manukau City, Papakura District, Franklin District, Waikato District, Hamilton City, and Hauraki District. The controlled items may not be moved into, within, or from these areas without the permission of an officer under the Biosecurity Act 1993.

The lower level of control applies to the rest of the North Island, and any other parts of New Zealand other than the South Island. The controlled items may not be moved from these areas to the South Island without the permission of an officer under the Biosecurity Act 1993.

Any person who wishes to obtain permission to move one of the controlled items should phone (09) 256-9395.

The controlled area will remain in force until the survey has determined the mite’s distribution. There will be further controls on movements of these items from the North to South Islands.

What beekeepers to look for on hives

Infested hives may show the following signs:

Unexpectedly low bee numbers

A patchy pattern on brood frames as would be seen with a heavy sacbrood infestation

Small reddish-brown mites on the bodies of bees, and on uncapped drone pupae

Weak crawling bees, possible with deformed wings

Sudden hive crashes.

For any concerns telephone the MAF Exotic Disease Hotline at 0800 809 966

Background

Varroa jacobsoni is a small, reddish-brown oval mite 1-2 mm long, which is found on the outside of adult honey bees. It can be seen with the naked eye if bees are examined carefully. It is also visible on honey bee pupae, and appears as a dark reddish-brown dot. It is most commonly found on drone pupae. The mite does not affect humans, and has no known host other than the honey bee.

The mite originated in eastern Asia and spread into Europe via Russia. Since the 1980s it has been carried into most other beekeeping regions of the world, killing thousands of colonies. Until now New Zealand and Australia have been considered the only major beekeeping countries free of the mite.

The mite lives by feeding on bee pupae. Infected pupae fail to survive, or may be born with deformed wings. Eventually, the mite population increases to a point where all the bees in the beehive die. This can take up to three years from the original infestation.

The mite spreads naturally from hive to hive by bee contact. However, the rapid spread of the mite worldwide is due to human activities. Modern beekeepers shift their hives long distances to pollinate crops, or gather honey. This enabled the Varroa mite to spread over the whole North American continent within five years of being introduced. Some European countries, which have strictly controlled the movement of bees, have managed to greatly slow the spread of Varroa. Another means of spread is the international trade in live bees. Queen bees are shipped worldwide, and are believed to be responsible for the spread of the mite from Europe to both North and South America.

New Zealand has prohibited the import of live bees for the last 40 years to protect our bee health status. This has led to New Zealand becoming a major exporter of live bees and queens to the Northern Hemisphere. This annual $1.8 million trade is threatened by the discovery of the Varroa mite.