然而NRDC的蜜蜂研究專家和律師相信，美國環保署經過調查後，已有證據顯示殺蟲劑和「蜜蜂群衰竭失調症」（colony collapse disorder，CCD）──蜜蜂群相繼失蹤與死亡──的謎團有關，但是他們卻沒有將此訊息公諸於世。這項消息的重要性不容忽略，因為蜜蜂群傳粉攸關美國約九成作物，總值150億美金的商業利益，包括蘋果、桃、梨、南瓜、筍瓜、小黃瓜、櫻桃、胡椒、黃豆、杏仁、腰果和向日葵等，都需要蜜蜂的授粉來生長果實。
自2006年蜜蜂群衰竭失調症問題浮現後，至今美國已有三分之一的蜜蜂被認定為因此症死亡或失蹤。根據2008年5月美國蜜蜂養殖觀察會（Apiary Inspectors of America）公佈的研究調查，2007年9月至2008年3月之間蜂場共損失36%的蜜蜂，往年這段期間損失量是31%。
The nonprofit Natural Resources Defense Council filed a lawsuit Monday in federal court in Washington DC to force the federal government to disclose studies on the effect of a new pesticide on honey bees. Studies on the pesticide, clothianidin, were ordered by the U.S. Environmental Protection Agency from the pesticide's manufacturer, Bayer CropScience, in 2003 when the federal agency granted the company a registration for the chemical.
An NRDC bee researcher and the organization's attorneys believe that the EPA has evidence of connections between pesticides and the mysterious honey bee die-offs reported across the country called "colony collapse disorder," or CCD, that it has not made public. The connection is important because commercial honey bees pollinate about 90 of the country's crops, valued at $15 billion. Apples, peaches, pears, pumpkins, squash, cucumbers, cherries, berries, peppers, squash, soybeans, almonds, cashews, and sunflowers all require or benefit from honey bee pollination.
The EPA has failed to respond to the NRDC's Freedom of Information Act request for agency records concerning the toxicity of pesticides to bees, prompting Monday's legal action. "Recently approved pesticides have been implicated in massive bee die-offs and are the focus of increasing scientific scrutiny," said NRDC attorney Aaron Colangelo. "EPA should be evaluating the risks to bees before approving new pesticides, but now refuses to tell the public what it knows." "Pesticide restrictions might be at the heart of the solution to this growing crisis, so why hide the information they should be using to make those decisions?" Calangelo asked.
The EPA has issued a fact sheet on clothianidin, one of a relatively new class of insecticides known as neonicotinoids that impact the central nervous system of insects. Maryann Frazier, who works with Pennsylvania State University as an extension associate in entomology, says in a paper on neonicotinoids and bees that, "There is conflicting information about the affects of neonicotinoids on honey bees, and different chemicals in this class are known to vary in their toxicity to bees, however the EPA identifies both imidacloprid and clothianidin as highly toxic to honey bees."
The EPA fact sheet says of clothianidin, "It has the potential for toxic chronic exposure to honey bees, as well as other non-target pollinators through the translocation of clothianidin resides in nectar and pollen. In honey bees, the affects of this toxic chronic exposure may include lethal and/or sub-lethal effects in the larvae and reproductive effects on the queen."
In addition, says Frazier, "there is concern about the practice of combining certain insecticides and fungicides." She cites a North Carolina University study found that some neonicotinoids in combination with certain fungicides, synergized to increase the toxicity of the neonicotinoid to honey bees over 1,000 fold in lab studies.
Colony collapse disorder has claimed more than one-third of honey bees in the United States since it was first identified in 2006. A survey by the Apiary Inspectors of America published in May found that losses of honey bees nationwide topped 36 percent of managed hives between September 2007 and March 2008, compared to a 31 percent loss during the same period a year earlier.
The chemical is sold under the brand name "Poncho" by Bayer AG in Germany, where it was banned in May after an unauthorized release that Bayer blames on an "extremely rare" "application error." In fact, Germany banned the entire class of neonicotinoids.
Another Bayer neonicotinoid, imidacloprid, has been blamed in France and South Dakota for colony collapse disorder. In South Dakota, farmers are suing, and the French government has banned the chemical for use on sunflower seeds. Scientists have not yet pinned down the cause of colony collapse disorder but they believe it is linked in part to pesticides.