From http://www.forbes.com/sites/jonentine/2014/02/05/bee-deaths-reversal-as-evidence-points-away-from-neonics-as-driver-pressure-builds-to-rethink-ban/:
Quote:
A split has developed in the research community as to the potential link of neonics to bee deaths. Just this past week, entomologists at a New Orleans conference released details from a soon-to-be published field study that concluded that neonics may not be as harmful to bees as portrayed in the media because they are not being expressed in plant pollen or the plant?s reproductive parts at levels that are high enough to hurt the bees.
?When we look at the literature and the Internet, what it says is that neonicotinoids applied as seed treatments are then taken up into the plant and expressed in the pollen and in the nectar,? said primary researcher Gus Lorenz, an extension entomologist with the University of Arkansas. ?Well, that?s not so much what we found.?
The researchers evaluated treated corn, soybeans and cotton. When they tested soybean flowers and cotton nectar, they found no traces of neonics at all. They did find microscopic traces of neonics in corn at what the EPA and toxicologists say are insignificant impact levels, with the highest having a mean of 2.3 parts per billion. To put that into perspective, one part per billion equals one second in 32 years. ?It?s not being expressed in the reproductive parts of the plants,? concluded Dr. Lorenz.
Yet those direct field observations conflict with some laboratory-based studies in leading journals and others in pay-to-play type publications in which bees treated in the lab with neonics are then released into the environment. In a French based study published in Science, a small percentage of free-ranging honeybees whose brains were doused with the neonic thiamethoxam got confused, failing to return to the hive. Another Science study, focusing on bumblebees, found those exposed to high doses of the neonic imidacloprid had reduced colony growth rates and produced significantly fewer queens to found new colonies. Just last month, research in the low-impact journal Excotoxicology concluded that bumblebees exposed to imidacloprid were somewhat worse at gathering pollen than untreated bees although the nectar foraging efficiency of treated bees was not significantly different than the controls. Last year, the European Food Safety Authority (EFSA) released three studies, none conclusive, raising questions about the potential role of neonics in bee health.
While concerning, the way some of the research was conducted raises caution about how much weight to place on their findings independent of real world confirmation. For example, the French thiamethoxam study came under sharp criticism because bees do not encounter the chemical by having their brains directly exposed. Any pesticide, if misapplied to crops, could collaterally impact bee function; that?s one key reason why farmers, at the urging of scientists, phased out organophosphates. But that doesn?t answer the question driving the current regulation frenzy: Are neonicotinoids as they are used in the real world the driving force behind bee deaths?
The US Agriculture Department and the EPA convened a working group two years ago to address that very question. Their report, issued last May, put activists back on their heels. It concluded that neonics, while a contributor, were way down the list of possible causes. They cited as the primary drivers colony management, viruses, bacteria, poor nutrition, genetics and habitat loss. By far the biggest culprit?the report called it ?the single most detrimental pest of honeybees??was identified as the parasitic mite varroa destructor?the likely cause of the 2004 die-off.
05 Jul 2014, 11:36 pm
I never said it was one particular case,there are many factors.
