While most people probably associate bees with their nettlesome sting, the insect is critical to sustaining life on earth, pollinating 80% of all flowering plants and some three-quarters of this country's fruits, nuts, and vegetables. The loss of the bee population would be devastating to U.S. agriculture.

Watching bees fly from flower to flower in your garden might have you thinking that's not much of a concern, but colony collapse disorder, or CCD, is a large and growing threat and it has not only beekeepers and farmers worried, but those likely most responsible for it: the agri-giants like Bayer, Dow Chemical (DOW), and Monsanto (MON).

Honeybees in particular are suffering from the malady, which even the Agriculture Department is forced to admit is likely the result of overreliance on pesticide use, though it lists it after other possible causes such as disease, nutrition, and stress.

CCD is the lack of adult honeybees present in a hive even, though there is a live queen. Moreover, no dead honeybee bodies are found around the hive, there's still honey in the hive, and immature bees are present. The colony becomes like some bee ghost town.

Some bee farmers report losing as much as 90% of their hives from the disorder with estimates ranging as high as one-third of all colonies having been lost since 2005. Because certain virus-transmitting parasites have frequently been found in hives hit by CCD, the chemical makers are quick to point to them as the cause of the collapse and a report issued last month by a USDA panel that included representatives from Bayer, Dow, and Syngenta (NYSE: SYT), said that while pesticide use could be a concern particularly in high dosages, "it is not clear, based on current research, whether pesticide exposure is a major factor associated with U.S. honey bee health declines in general." 

Yet the European Food Safety Authority, which apparently doesn't have such a vested interest in protecting the corporations as does the USDA, has found chemicals like Bayer's clothianidin and imidacloprid, along with Syngenta's thiamethoxam, an "unacceptable" danger to bee populations. 

The three chemicals make up what are known as neonicotinoids, nerve agents that are used to treat about one-third of the U.S.'s planted crops. Together they are used to treat 94% of U.S. corn, 100% of canola, three-quarters of all sorghum, and two-thirds of our sugar beet crop. A number of recent studies also point to the "neonics" as a prime suspect in CCD.

Critics also highlight the proliferation of genetically modified crops, particularly Monsanto's MON810 corn that has been altered to kill insects that try to eat it, as another culprit killing off bees. Austria, France, Germany, Greece, Hungary, and Poland have gone so far as to completely ban it, with the latter doing so particularly because of its connection to CCD.

Naturally the chemical manufacturers say the concerns are overblown, with sufficient study in the field proving the chemicals' safety. Yet in a bid to contain what damage might be done to their investment, the chemical makers have also begun studying bee health in earnest themselves. Bayer has opened "bee care centers," Syngenta is funding research into CCD, and Monsanto even purchased the leading bee research firm Beelogics. 

While such investments would seem to show concern for the health of bees, it's also pretty much a case of the fox guarding the henhouse. Beelogics was one of the leading researchers into CCD, and now one of the possible culprits owns it. I think Monsanto cares not so much for the research conclusions per se but rather its work in genetically modifying the bees themselves. It is seeking patent protection for its RNAi-based -- meaning the bees' genetic code -- treatment, which raises the obvious threat of what happens to the beekeepers whose bees get crossbred with Monsanto's? If history with its seeds is any guide, it will go after them legally for violating their patents. 

Ultimately, Monsanto and the other biotechs need more than just a stinging rebuke from investors for their role in causing the collapse of bee colonies and the threat it poses to our food supply.