Showing posts with label polinate. Show all posts
Showing posts with label polinate. Show all posts

Thursday, April 4, 2013

Mystery Malady Kills More Bees, Heightening Worry on Farms

BAKERSFIELD, Calif. — A mysterious malady that has been killing honeybees en masse for several years appears to have expanded drastically in the last year, commercial beekeepers say, wiping out 40 percent or even 50 percent of the hives needed to pollinate many of the nation’s fruits and vegetables.

A conclusive explanation so far has escaped scientists studying the ailment, colony collapse disorder, since it first surfaced around 2005. But beekeepers and some researchers say there is growing evidence that a powerful new class of pesticides known as neonicotinoids, incorporated into the plants themselves, could be an important factor.

The pesticide industry disputes that. But its representatives also say they are open to further studies to clarify what, if anything, is happening.

“They looked so healthy last spring,” said Bill Dahle, 50, who owns Big Sky Honey in Fairview, Mont. “We were so proud of them. Then, about the first of September, they started to fall on their face, to die like crazy. We’ve been doing this 30 years, and we’ve never experienced this kind of loss before.”

In a show of concern, the Environmental Protection Agency recently sent its acting assistant administrator for chemical safety and two top chemical experts here, to the San Joaquin Valley of California, for discussions.

In the valley, where 1.6 million hives of bees just finished pollinating an endless expanse of almond groves, commercial beekeepers who only recently were losing a third of their bees to the disorder say the past year has brought far greater losses.

The federal Agriculture Department is to issue its own assessment in May. But in an interview, the research leader at its Beltsville, Md., bee research laboratory, Jeff Pettis, said he was confident that the death rate would be “much higher than it’s ever been.”

Following a now-familiar pattern, bee deaths rose swiftly last autumn and dwindled as operators moved colonies to faraway farms for the pollination season. Beekeepers say the latest string of deaths has dealt them a heavy blow.

Bret Adee, who is an owner, with his father and brother, of Adee Honey Farms of South Dakota, the nation’s largest beekeeper, described mounting losses.

“We lost 42 percent over the winter. But by the time we came around to pollinate almonds, it was a 55 percent loss,” he said in an interview here this week.

“They looked beautiful in October,” Mr. Adee said, “and in December, they started falling apart, when it got cold.”

Mr. Dahle said he had planned to bring 13,000 beehives from Montana — 31 tractor-trailers full — to work the California almond groves. But by the start of pollination last month, only 3,000 healthy hives remained.

Annual bee losses of 5 percent to 10 percent once were the norm for beekeepers. But after colony collapse disorder surfaced around 2005, the losses approached one-third of all bees, despite beekeepers’ best efforts to ensure their health.

Nor is the impact limited to beekeepers. The Agriculture Department says a quarter of the American diet, from apples to cherries to watermelons to onions, depends on pollination by honeybees. Fewer bees means smaller harvests and higher food prices.

Almonds are a bellwether. Eighty percent of the nation’s almonds grow here, and 80 percent of those are exported, a multibillion-dollar crop crucial to California agriculture. Pollinating up to 800,000 acres, with at least two hives per acre, takes as many as two-thirds of all commercial hives.

This past winter’s die-off sent growers scrambling for enough hives to guarantee a harvest. Chris Moore, a beekeeper in Kountze, Tex., said he had planned to skip the groves after sickness killed 40 percent of his bees and left survivors weakened.

“But California was short, and I got a call in the middle of February that they were desperate for just about anything,” he said. So he sent two truckloads of hives that he normally would not have put to work.

Bee shortages pushed the cost to farmers of renting bees to $200 per hive at times, 20 percent above normal. That, too, may translate into higher prices for food.

Precisely why last year’s deaths were so great is unclear. Some blame drought in the Midwest, though Mr. Dahle lost nearly 80 percent of his bees despite excellent summer conditions. Others cite bee mites that have become increasingly resistant to pesticides. Still others blame viruses.

But many beekeepers suspect the biggest culprit is the growing soup of pesticides, fungicides and herbicides that are used to control pests.

While each substance has been certified, there has been less study of their combined effects. Nor, many critics say, have scientists sufficiently studied the impact of neonicotinoids, the nicotine-derived pesticide that European regulators implicate in bee deaths.

The explosive growth of neonicotinoids since 2005 has roughly tracked rising bee deaths.

Neonics, as farmers call them, are applied in smaller doses than older pesticides. They are systemic pesticides, often embedded in seeds so that the plant itself carries the chemical that kills insects that feed on it.

Older pesticides could kill bees and other beneficial insects. But while they quickly degraded — often in a matter of days — neonicotinoids persist for weeks and even months. Beekeepers worry that bees carry a summer’s worth of contaminated pollen to hives, where ensuing generations dine on a steady dose of pesticide that, eaten once or twice, might not be dangerous. More

Given that these useful insects polinate many of our food crops we really need to solve this issue as soon as possible. It may be that neonicotinoids need to be banned immediatly before the situation gets worse. We cannot afford to take chances with our food security. Editor

 

Wednesday, March 27, 2013

Neonicotinoid pesticides 'damage brains of bees'

Commonly used pesticides are damaging honey bee brains, studies suggest.

Scientists have found that two types of chemicals called neonicotinoids and coumaphos are interfering with the insect's ability to learn and remember.

Experiments revealed that exposure was also lowering brain activity, especially when the two pesticides were used in combination.

The research is detailed in two papers in Nature Communications and the Journal of Experimental Biology.

But a company that makes the substances said laboratory-based studies did not always apply to bees in the wild.

And another report, published by the Defra's Food and Environment Research Agency (Fera), concluded that there was no link between bee health and exposure to neonicotinoids.

The government agency carried out a study looking at bumblebees living on the edges of fields treated with the chemicals.

Falling numbers

Honey bees around the world are facing an uncertain future.

They have been hit with a host of diseases, losses of habitat, and in the US the mysterious Colony Collapse Disorder has caused numbers to plummet.

Start Quote

It would imply that the bees are able to forage less effectively”

Dr Sally WilliamsonNewcastle University

Now researchers are asking whether pesticides are also playing a role in their decline.

To investigate, scientists looked at two common pesticides: neonicotinoids, which are used to control pests on oil seed rape and other crops, and a group of organophosphate chemicals called coumaphos, which are used to kill the Varroa mite, a parasite that attacks the honey bee.

Neonicotinoids are used more commonly in Europe, while coumaphos are more often employed in the United States.

Work carried out by the University of Dundee, in Scotland, revealed that if the pesticides were applied directly to the brains of the pollinators, they caused a loss of brain activity.

Dr Christopher Connolly said: "We found neonicotinoids cause an immediate hyper-activation - so an epileptic type activity - this was proceeded by neuronal inactivation, where the brain goes quiet and cannot communicate any more. The same effects occur when we used organophosphates.

"And if we used them together, the effect was additive, so they added to the toxicity: the effect was greater when both were present."

Another series of laboratory-based experiments, carried out at Newcastle University, examined the behaviour of the bees.

The researchers there found that bees exposed to both pesticides were unable to learn and then remember floral smells associated with a sweet nectar reward - a skill that is essential for bees in search of food.

Dr Sally Williamson said: "It would imply that the bees are able to forage less effectively, they are less able to find and learn and remember and then communicate to their hive mates what the good sources of pollen and nectar are."

'No threat'

She said that companies that are manufacturing the pesticides should take these findings into account when considering the safety of the chemicals.

Start Quote

Decisions on the use of neonicotinoids must be based on sound scientific evidence”

Ian BoydDefra

She explained: "At the moment, the initial tests for bee toxicity are giving the bees an acute dose and then watching them to see if they die.

"But because bees do these complex learning tasks, they are very social animals and they have a complex behavioural repertoire, they don't need to be killed outright in order not to be affected."

The European Commission recently called for a temporary moratorium on the use of neonicotinoids after a report by the European Food Safety Authority concluded that they posed a high acute risk to pollinators.

But 14 out of the 27 EU nations - including the UK and Germany - opposed the ban, and the proposal has now been delayed.

Ian Boyd, chief scientist at Defra, said: "Decisions on the use of neonicotinoids must be based on sound scientific evidence." More