Bee shortage set to sting growers

A decrease in hive numbers because of the varroa mite (right) could have severe impacts on pollination of new plantings.

A shortage of bees to pollinate new plantings could cost tens of millions of dollars in lost horticultural production.

With the varroa mite expected to develop resistance to chemical treatments, the problem of hive losses will be exacerbated, says Hamilton-based HortResearch scientist Mark Goodwin.

The bee shortage also has strong potential to hurt pastoral farming if it reduces grass growth because of less clover to help fix nitrogen in the soil, he said.

Pollination of most flowering plants in New Zealand occurs either partly or fully by insect activity.

A briefing paper - by Goodwin, HortResearch colleague Michelle Taylor and Sandy Scarrow of Fruition Horticulture - looked at the ongoing concerns about bee shortages due to the varroa mite, and increased cropping and horticulture.

An article based on the paper in The Orchardist magazine said beekeepers were facing a variety of major biosecurity and economic threats.

The number of managed bee colonies has already dropped from 340,000 in 1990 to 293,000 last year.

While there was a steady increase in hive numbers between 1995 and 2000 due to good honey prices, there has been a decline since 2000, mainly due to the varroa mite.

It was estimated the anticipated increase in demand for hives would result in a small shortfall of 4200 within 10 years. If varroa had the same impact in the South Island as the North, there could be a 3000-hive shortfall by 2010.

The article also warned that declining honey prices may fall to the point where many beekeeping operations were no longer profitable, and numerous biosecurity threats such as European foulbrood could impact "severely" on the industry.

Under one scenario, the hive shortage in the immediate future could be 48,000 and rise to 73,000 by 2015.

It was expected that over the next 10 years there would be an increase in avocado, brassica, seed-clover, kiwifruit and pear plantings.

Goodwin said there was no formal analysis of the financial implications of hive shortages. But he believed the threats posed meant shortages could result in tens of millions of dollars' worth of horticultural production being stymied.

He also noted the paper's findings did not take into account the likely development of resistance by the varroa mite to chemical treatment or address the effect of a hive shortage on the development of clover in grazing pastures.

Resistance to varroa mite treatment was expected within five years. "We know it's happened everywhere else in the world. When that happens we can expect the [hive] losses to be much bigger than they are currently."

Horticulture New Zealand chief executive Peter Silcock said the entire industry's sales were worth about $4.7 billion a year, with $2.4 billion in exports. "A lot of these exports rely quite heavily on bees for pollination."

The industry was keen to stop a hive shortage developing.

He agreed potential losses of tens of millions of dollars were realistic. "If we don't have the pollination then that is exactly what will happen."

Beekeepers and grower representatives are working to mitigate the risks.

In the meantime, growers are being urged to look at measures such as reviewing the use of chemicals and developing hives themselves.


Hiving off

Peak demand for hives is in November, when an estimated 88,675 are required for pollination nationwide.

With increased planting, it is estimated 103,150 hives will be required in November 2010 and 108,675 by 2015.

Surveys of future beekeeping and planting intentions indicate shortfalls developing and these could grow significantly.