Newly published scientific evidence is bolstering calls for greater regulation of some of the world’s most widely used pesticides and genetically modified crops.

Earlier this year, three independent studies linked agricultural insecticides to colony collapse disorder, a phenomenon that leads honeybees to abandon their hives.

Beekeepers have reported alarming losses in their hives over the last six years. The USDA reports the loss in the United States was about 30 percent in the winter of 2010-2011.

Bees are crucial pollinators in the ecosystem. Their loss also impacts the estimated $15 billion worth of fruit and vegetable crops that are pollinated by bees in the United States.

The studies, conducted in the United States, France, and the United Kingdom, all pointed to neonicotinoids, a class of chemicals used widely in U.S. corn production, as likely contributors to colony collapse disorder. The findings challenged the EPA’s position—based on studies by Bayer CropScience, a major producer of the neonicotinoid clothianidin—that bees are only exposed to small, benign amounts of these insecticides.

The new studies found that bees are exposed to potentially lethal amounts of neonicotinoids in pollen and in dust churned up by farm equipment. They also found that exposure to neonicotinoids can reduce the number of queen bees and disorient worker bees.

An alliance of beekeepers and environmental groups filed a petition on March 21 asking the EPA to block the use of clothianidin in agricultural fields until the EPA conducts a sound scientific review of the chemicals.

Meanwhile, farm chemicals and the biotech industry have come under fire for the problem of pest resistance. Some weeds and bugs have become less susceptible or immune to the chemicals or biotechnology used to control them.

In March, national experts on corn pests published a letter to the EPA describing how rapidly rootworms are becoming resistant to the larvae-killing gene in Monsanto’s genetically engineered “Bt” corn. The letter warns that the EPA should move to regulate Bt corn—by requiring, for example, non-GM buffer zones—with “some sense of urgency.”

In a similarly alarming trend, Monsanto’s “Roundup Ready” soy and corn, which are genetically modified to tolerate the active ingredient in Roundup, are associated with the creation of “super weeds.” The widespread use of these crops has led farmers to vastly increased use of the herbicide, leading to the development of resistant weeds.

The agriculture industry has responded to Roundup’s failure by developing new crop varieties resistant to another pesticide/herbicide, 2,4-D. An ingredient of Agent Orange, 2,4-D is linked to birth defects, hormone disruption, and cancer. Last December, Dow AgroSciences LLC asked the U.S. Department of Agriculture to approve the new varieties for cultivation.