On March 28, How the World Works referenced a Der Spiegel article citing data from one relatively small study that offered shallow support for thinking there might be a connection between the spread of genetically modified Bt corn and the widely publicized mass death of honeybees around the world (referred to as "colony collapse disorder").

Pro-agricultural biotechnology journalists like Reason magazine's Ron Bailey quickly scoffed at the theory, and in fact, eagerly used its flimsiness to bash anti-GM activists who are probably over-eager to seize upon any scientific finding that supports their own fierce opposition to genetically modified crops. But the long-established bias of the pro-GM boosters made their own dismissals equally suspect.

The New York Times reporter, Alexei Barrionuevo, responsible for bringing colony collapse disorder (CCD) to national attention didn't do a whole lot to assuage fears when, in a follow-up piece looking at the scientific rush to figure out what was going on, he devoted one sentence to the topic: "[Scientists] have also set aside for now the possibility that the cause could be bees feeding from a commonly used genetically modified crop, Bt corn, because the symptoms typically associated with toxins, such as blood poisoning, are not showing up in the affected bees."

But now comes the most convincing argument I've seen so far, courtesy of the American Farm magazine (with thanks for the tip to the very pro-GM GMO Pundit) and Galen P. Dively, a professor at the University of Maryland who specializes in integrated pest management. Dively sums up the available research -- and there has been quite a bit on the possible effects of Bt corn on honeybees -- and states that "while this possibility has not been ruled out, the weight of evidence based on a multitude of studies argues strongly that the current use of Bt corn is not associated with CCD."

But he concludes:

Although there is no evidence thus far of any lethal or sub-lethal effects of the currently used Bt endotoxins on honey bees, insecticidal products expressed by other transgenes in crops may need extended field testing on a case-by-case basis to assess the longer term consequences of sub-lethal changes in colonies and subtle modifications in bee behavior.

This isn't the first time Dively has plunged into a Bt corn controversy. He was previously one of three authors of a study that concluded after two years of research that "the impact of Bt corn pollen from current commercial hybrids on monarch butterfly populations is negligible."

Does that put professor Dively in the "everything is all right with GM crops" camp? Perhaps. But if a campaign against GM crops is going to be based on the evidence, then so far, the disappearance of the world's honeybees might not be the best fodder for the crusade.