4 months ago | 268 notes | Reblog
mohandasgandhi: Purdue University Study: Honeybee Deaths Linked to Seed Insecticide Exposure Analyses of bees found dead in and around hives from several apiaries over two years in Indiana showed the presence of neonicotinoid insecticides, which are commonly used to coat corn and soybean seeds before planting. The research showed that those insecticides were present at high concentrations in waste talc that is exhausted from farm machinery during planting. The insecticides clothianidin and thiamethoxam were also consistently found at low levels in soil — up to two years after treated seed was planted — on nearby dandelion flowers and in corn pollen gathered by the bees, according to the findings released in the journal PLoS One this month. “We know that these insecticides are highly toxic to bees; we found them in each sample of dead and dying bees,” said Christian Krupke, associate professor of entomology and a co-author of the findings. The United States is losing about one-third of its honeybee hives each year, according to Greg Hunt, a Purdue professor of behavioral genetics, honeybee specialist and co-author of the findings. Hunt said no one factor is to blame, though scientists believe that others such as mites and insecticides are all working against the bees, which are important for pollinating food crops and wild plants. “It’s like death by a thousand cuts for these bees,” Hunt said. […] Seeds of most annual crops are coated in neonicotinoid insecticides for protection after planting. All corn seed and about half of all soybean seed is treated. The coatings are sticky, and in order to keep seeds flowing freely in the vacuum systems used in planters, they are mixed with talc. Excess talc used in the process is released during planting and routine planter cleaning procedures. “Given the rates of corn planting and talc usage, we are blowing large amounts of contaminated talc into the environment. The dust is quite light and appears to be quite mobile,” Krupke said. Krupke said the corn pollen that bees were bringing back to hives later in the year tested positive for neonicotinoids at levels roughly below 100 parts per billion. “That’s enough to kill bees if sufficient amounts are consumed, but it is not acutely toxic,” he said. On the other hand, the exhausted talc showed extremely high levels of the insecticides — up to about 700,000 times the lethal contact dose for a bee. (Continue reading…) Related: Honeybee problem nearing a ‘critical point’: Unusual honeybee die-offs have become so severe that some US beekeepers will qualify for disaster relief funds [Image via]