Honey bee losses defy solitary explanations

January 21, 2013

From: Western Farm Press


Harry Cline

Simple, one-word answers make money on Jeopardy. However, suggested solitary explanations as to what’s killing honey bees in North America and Europe are little more than buzzwords. There are so many suspected causes to why bees are dying they are umbrellaed under the term Colony Collapse Disorder (CCD). CCD encompasses everything from the varroa mite to bad beekeeping.


Opinions number almost as many as there are bees in a hive as to why the bee population in North America has declined almost 50 percent over the past two decades while at the same time the bee population is increasing elsewhere in the world, like in Asia where it is up 426 percent and in Africa where it has increased by 130 percent during the same period of time.


Most agree that the varroa mite and as many as 20 viruses it vectors is part of the CCD puzzle. Annette Schuermann, head of the Bayer Bee Care Center in Monheim, Germany said varroa mite losses in the U.S. total 30 percent.


That state of the art research center was opened last June. A similar center is under construction in Raleigh, N.C. and is scheduled to open later this year.


Bayer CropScience is interested in a worldwide bee population for a couple of reasons. Pollinating bees contribute significantly to the production of more than $200 billion dollars or 9.5 percent of the world’s agricultural production. Honey bee pollination is indirectly or directly responsible for one-third of the world’s food production, according to Bayer. And that is expected to increase as the world’s population increases and the consumption of tree nuts, fruits and vegetable grows, many of which require bee pollination to produce. Bayer CropScience is heavily invested in crop protection products for those markets.


Secondly, Bayer is heavily committed to a new class of insecticides called neonicotinoids and they have been widely implicated in honey bee kills. Neonicotinoids are neuro-active insecticides related to nicotine. The development of this class of insecticides began with work in the 1980s by Shell Oil Company and the in the1990s by Bayer.


The neonicotinoids were developed in large part because they are less toxic to mammals than organophosphatess and carbamate insecticides.


Neonicotinoids are the first new class of insecticides introduced in the last 50 years, and the neonicotinoid imidacloprid is currently the most widely used insecticide in the world. Recently, the use of some members of this class has been restricted in some countries due to evidence of imidacloprid effects on honey bees.


Beekeepers actually welcomed the neonicotinoids because there were fewer bee kills than when organophosphates and carbamates were used.


Recently, though, researchers in the U.S. and Europe are saying there is a link between bee deaths and neonincotidoid use. Maybe not directly, but in sub-lethal doses that make bees more susceptible to diseases. Bayer refutes that. Schuermann says if there is a correlation between bee kills and neonicotinoids is due to “incorrect” pesticide applications.

Weather and bee health


The new centers will serve as a scientific and communication platform to consolidate existing and future bee health projects from Bayer companies in cooperation with external partners. They will also foster information sharing and will provide a platform for discussion and new ideas. Bayer believes that this collaboration is essential in order to find sustainable solutions that will improve honey bee health. “The Bee Care Program and the establishment of the Bee Care Centers will bring Bayer’s extensive experience and knowledge in bee health under one roof and will ensure that dedicated resources for bee health are available,” says Wolfgang Plischke, member of the Bayer AG Board of Management responsible for Innovation, Technology and Environment.


Schuermann told a group of growers and journalists visiting the center in Germany as part of Bayer’s recent Vegetable Forum that the company believes there are many factors contributing to CCD. One is the increasing use of bees in agriculture and long distance movement of bees. This, she says, increases the chance of disease and mite spread.


Weather also plays a role in bee health.


Bayer is developing a product to stop mites from entering the hive, thus precluding deadly pathogens from entering. The company is also working with new pesticide application technology to spray pesticides from the bottom of the plant up, rather than over the top. This, hopefully, will reduce pesticide exposure to the bees.


Grass Valley, Calif., beekeeper and popular blogger Randy Oliver, said while beekeepers are thrilled that the switch from organophosphates and carbamates to neoincotinoids have greatly reduced bee kills, there remain several unresolved issues and unanswered questions about these insecticides.


No crop is more dependent on bees than California’s 800,000 acres of almonds. Nearly 1 million hives are trucked into California each winter for pollination services for the state’s almonds. California beekeepers supply the remaining 500,000 hives needed.


Eric Mussen, University of California apiculturist says hive strength has improved over the last few years, and attributes stronger hives to beekeepers who have found ways to overcome losses.


He says beekeepers have found ways to improve hive health and strength. Above average rainfall in 2011 California also provided a higher level of nutrition for foraging honey bees. Mussen said that added nutrition could make a significant difference in honey bee health.

Strong bee colonies


In his 2013 bee supply outlook, Bakersfield, Calif., beekeeper Joe Traynor says getting strong bee colonies for almonds (8 to 10 frames of bees) will be a much tougher task for the 2013 season than it has been in recent years. He cites two reasons for that:


• Loss of the most effective chemical for varroa mite control.

• Poor bee forage last year due to drought conditions in most bee areas.


The most effective varroa control chemical became unavailable in last year when the overseas manufacturer stopped production. Beekeepers that stockpiled the material in 2011 got good varroa control in 2012. “Some beekeepers had to use alternate materials and found their colonies weakened to the point where many perished or were too far gone to nurse back to almond pollinating strength. There is a crying need for effective varroa-control products. The difficulty in controlling this pernicious pest with approved products is causing some beekeepers to improvise their own varroa treatments,” Traynor said.


Drought conditions have left bee colonies in many areas in a weakened nutritional state, making them more susceptible to varroa mites and its associated viruses. “This one-two punch from varroa and drought will result in above average winter losses of bees and overall weaker bee colony strength for almonds,” he said. “Some beekeepers are predicting $200 per colony bee rental prices for almonds for the few growers that haven’t yet contracted for bees or for growers whose beekeepers jumped ship because they didn’t feel they were getting a fair price.”

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