Bees have a vital role to play in food production and agriculture. They are extremely good pollinators of crops and contribute substantially to New Zealand’s multi-billion dollar agricultural economy.
Pollination is essential for plants to produce fruits and seeds, and to assist with nitrogen regeneration in clover pastures. Because healthy bee populations are so important for the productivity of New Zealand agriculture, we need to protect them.
Fortunately, our honey bee population continues to grow. New Zealand now has a total of around 880,000 registered beehives – almost double the figure of six years ago. This does not mean that we can be complacent. There is still work to be done to protect bee health.
The Ministry for Primary Industries released findings of the 2018 NZ Colony Loss and Survival Survey in April. The survey shows that hive losses averaged 10.2 percent. This is lower than overseas rates, but indicates that we still need to address the issues that are damaging our bee populations and dedicate resources to fixing them.
The leading causes of bee loss are attributed to queen problems, varroa mites, starvation and wasps, according to the annual survey.
Colony deaths from queen problems accounted for over a third of losses during the 2018 winter season. The parasitic varroa mite – which feeds on bees – accounted for almost 20 percent, followed by starvation and wasps.
Queen problems were mainly due to drone-laying queens and queen failure. Both problems were more pronounced in older queens.
The varroa mite, first detected in New Zealand in 2000, has destroyed most wild bee colonies. Without treatment, most colonies die within six months of becoming infected. The mite caused our registered beehive numbers to drop to around 250,000 hives in the mid-2000s. Numbers only started increasing a decade ago. Since then, it’s increased more than three-fold. Managing the mite is vital, especially for those that have become resistant to treatment.
Wasps kill honey bee colonies in winter by robbing their honey stores and/or by seeking protein to feed their own young.
Starvation may be a symptom of excessive competition for nectar and pollen sources and is symptomatic of the rapid increase in colony numbers.
The challenges for beekeepers include competition for apiary sites and overcrowding. Loss rates were highest in the upper North Island and the middle of the South Island, with the lowest rates in the lower North Island.
On average, losses attributed to suspected toxic exposure comprised of 1.9% of losses among commercial beekeepers, compared with 2.4 percent the previous year.
Having many dead bees in or in front of the colony is indicative of exposure to environmental toxins such as plant toxins and chemicals. The survey does not distinguish between naturally occurring karaka poisoning and agrichemicals. Exposure to toxicity was qualitatively lower among large commercial beekeepers.
Taking care when spraying around bees – or arranging for hives to be moved will help protect them.
The report shows that we have to make sure our bees are well-fed and protected from pests. But, overall, our bee population is thriving – which is good news.
The survey is critical not only because it informs us on bee health, but because it allows us to make better choices to protect our bee population and to track changes on colony loss and survival for the future.
As a champion of bees, Agcarm will continue to work with the bee industry and the wider agricultural sector to help ensure a healthy bee population.