The onset of autumn always brings heightened advertising for grub control products for lawns. With the winter of 2007-2008 not far off, however, comes an urgent reminder from beekeepers about Colony Collapse Disorder (CCD), which wiped out tens of thousands of hives of bees across North America last winter and spring.

That desire for a grub-free lawn has placed some homeowners and landscape contractors in direct conflict with the bee industry. And even as new highly touted research points to new strains of bee viruses as the cause of the decline, the men and women who tend the hives still point to the world’s most commonly used pesticide.

“The issue is that the primary product used to control grubs contains a chemical compound known as imidacloprid, which is most commonly marketed as Merit,” said Paul Tukey, founder and spokesman for SafeLawns.org, a national nonprofit organization. “Imidacloprid is known to be toxic to bees, and many beekeepers see a direct link to this chemical and the disappearance of bee hives. Many countries are employing the ‘precautionary principle’ and pulling products containing imidacloprid from the shelves. But in the U.S., homeowners and farms are using more and more of it, especially since many competing products (which relied on the compound diazinon to kill grubs and other insects) have already been banned due to their proven toxicity.”

Colony Collapse Disorder is a term coined in 2006 as catch phrase for a disturbing, unexplained phenomenon that caused nearly a quarter of U.S. honeybee colonies to disappear within a few months. Though many thought the problem was limited to western North America, beekeepers across the United States, Canada and Europe also reported the problem that is posing a threat to the world’s food supply.

In addition to the production of honey, honeybees pollinate approximately one-third of the food consumed by Americans, according to a Cornell University study. Among the most common crops that require pollination by bees are nuts, soybeans, squash and cucumbers. Numerous fruits also need bees, including apples, citrus, avocados, peaches, kiwi, cherries, blueberries, cranberries, strawberries, blueberries, cantaloupe and other melons. In all, the bee pollination industry is worth $14-$20 billion.

The cause of CCD is greatly disputed, with the most recent high-profile theory involving a newly discovered disease dubbed Israeli Acute Paralysis Virus (ADPV) that was detailed in a scientific paper released Sept. 4. Many beekeepers, and other scientists,  believe the problem to be related to increased imidacloprid use. In addition to lawn dwelling grubs, other target insects include aphids, whiteflies, thrips, mealybugs and beetles. Products that contain imidacloprid include Admire, Confidor, Connect, Evidence, Leverage, Muralla, Provado, Trimax, Premise and Winne.

Though imidacloprid has been patented since 1988, its use on American crops escalated significantly in the past three years, just as products containing Diazinon came off store shelves. In the case of bees, the imidacloprid apparently does not directly kill the colonies, but may disorient the bees and cause them to disband — at least according to beekeepers who are closely observing bees’ behavior.

“Before last November I knew very little about (imidacloprid),” said David Hackenberg, owner of Hackenberg Apiaries in Lewisburg, Pa., and past president of the American Beekeeping Association. “In the past few months I have come to know more than I want to know about this newer type of pesticide. From what I have learned so far, I am convinced that imidacloprid plays a role in CCD.”

Eric Lane agrees. The California beekeeper said he can trace the origin of Colony Collapse Disorder to 2003, the year imidacloprid was approved for use in his state. He estimates he lost 80 percent of his bees last winter and said he was not surprised, based on his prior research.

“When an adult bee goes out to forage for pollen (on plants affected by imidacloprid), by the fourth day the bee loses the ability to smell,” he said. “Young bees do their normal duties around the hive for five days. Then they go and fill up with nectar and realize they don’t know where home is. Old bees hang around the hive but eventually wander off and die. Young bees fly off and never come home.”

Hackenberg, Lane and many others are calling on farmers and homeowners to eliminate the use of Merit and other products containing imidacloprid, at least until someone can prove that the chemical is not the problem. Bayer AG, the aspirin and chemical manufacturerthat holds the patent on imidacloprid, has reportedly paid for dozens of laboratory tests and sharply denounces any claims that its product harms bees when it is applied according to directions. Research at Penn State and elsewhere, however, has suggested potential links to bee decline and the new pesticide.

“If bees are eating fresh or stored pollen contaminated with these chemicals at low levels, they may not cause mortality but may impact the bees’ ability to learn or make memories,” stated a Penn State report published in December 2006. “If this is the case, young bees leaving the hive to make orientation flights may not be able to learn the location of the hive and may not be returning, causing the colonies to dwindle and eventually die.”

Dr. Jerry J. Bromenshenk, a research scientist at the University of Montana is a member of the nationwide CCD working group of scientists that convened to study the phenomenon last year. Though he said he is still skeptical that imidacloprid is the entire cause of the bee decline, he has testified on behalf of beekeepers who have lost hives due to imidacloprid exposure.

“The problem is that imidacloprid and similar chemicals were supposed to have been used in controlled, specific situations,” he said. “Now we have people drenching it into the soil and applying in by air as a foliar application. In those situations, absolutely, you’re laying yourself open for a bee poisoning event.”

In Florida, where CCD was first observed in 2006, Dr. Jerry Hayes also sits on the CCD working group. As the state’s head bee inspector and expert, he is calling on the government to get more involved with emergency research and funding.

“I’m coming from a government bureaucratic environment here, but the proper course of action would be to get the scientific data that proves this, submit the scientific data to the EPA and then they would have no choice but to pull the products,” he said.

The U.S. government is certainly aware of the problem. In June, Senators Barbara Boxer and Hilary Clinton co-sponsored legislation to protect bees. In a report published that same month by the Congressional Research Service, imidacloprid was named as a likely cause of the bees’ demise.

“The scientists studying CCD note that the doses taken up by bees are not lethal, but they are concerned about possible chronic problems caused by long-term exposure,” according to the CRS report. “As noted by the National Research Council, some studies report sublethal effects of pesticides that may impair the navigational and foraging abilities of honeybees.”

Lawmakers in France and several other European countries have long restricted certain applications of imidacloprid based on evidence that the product harms bees. In Canada, the Sierra Club has taken a particularly strong stand against imidacloprid’s impact on species other than bees. “It has been shown to cause acute health effects, including spasms and thyroid lesions,” the Sierra Club stated. “No chronic toxicity tests have been made available to the public, but we do know that it has effects on mammalian reproduction. The reproductive health of birds is also affected, with reduced egg production and egg thinning. It affects a multitude of beneficial insects, as well as earthworms.”

According to registration papers filed with the U.S. Environmental Protection Agency, imidacloprid is moderately toxic to humans, and manufacturers are required to place a “Caution” or “Warning” designation on product labels. The EPA further classifies imidacloprid as highly toxic to bees and upland game birds.

The most recent scientific study — which was touted as possibly unlocking the cause of bee decline in many national news reports on Sept. 5 — doesn’t carry much weight with many beekeepers. The scientists authoring the report noted that bees affected by Israeli Acute Paralysis Virus are typically found dead outside their hives. In virtually all known cases of Colony Collapse Disorder, the bee carcasses are never found.

“The viruses are a symptom, but not the cause,” said Lane, whose family has been beekeepers since the 1850s. “The imidacloprid breaks down the bees’ immune systems so they’re susceptible to every new virus that comes down the road.”

For further evidence, many observers point to the world’s organic beekeepers — who don’t allow their bees on crops where pesticides are applied. No known organic beehives have experienced Colony Collapse Disorder.

Given all of this information, many American farmers aren’t willing to take any chances and are forsaking all products containing imidacloprid, which puts them in step with European farmers and with the common sense based Precautionary Principle.

“Pollination is so important to us, we agreed not to use these new materials,” said Darren Hammond, farm manager for Jasper Wyman & Sons of Maine, the nation’s largest producer of wild blueberries. “Our primary competitor and all of our outside growers have also agreed not to use these products. We’re not saying there’s definitely a link between bees and imidacloprid; that’s for the researchers to decide. We’re just not willing to take the risk.”

The whole mess leaves many homeowners in a quandary this fall, just as many companies begin advertising promotions for grub control products such as Merit. Grubs, which are the larvae of flying and chewing insects including Japanese beetles and European chafers, cause lawn damage by eating grass roots. Skunks and moles also can make a mess of a lawn when they tunnel and claw in search of the grubs as a food source.

To combat grub infestations, Tukey suggests other approaches that don’t involve chemicals, including the use of naturally occurring beneficial nematodes, which are nontoxic, as well as organic soil management. 

“In acute cases, application of the nematodes may be necessary to control many species of grubs in the lawn,” Tukey said. “The fact is, though, that lawns grown with organic methods are going to be far more resilient to grub damage. Naturally occurring soil organisms will most often keep grub populations in check as long as those organisms are not killed off by chemical fertilizers and pesticides.”

The issue of imidacloprid and bees, according to Tukey, is yet another reason why homeowners should always be careful when considering chemicals in their lawn care and landscaping.

“Time and time again these chemical products have proven to be questionable for either our health, our pets’ health or the environment in general,” said Tukey, author of The Organic Lawn Care Manual. “At SafeLawns.org, we’re committed to promoting organic alternatives that don’t present these same risks.”

Chemicals, nearly all chemicals, pose risks if used improperly; some are problems no matter what.

“For generations, every time a new classification of chemicals is introduced to the public, it comes with unexpected consequences,” said Dr. Bromenshenk. “In the case of imidacloprid, the recent widespread use is a major concern and I don’t think the warning labels go far enough to protect the American public.”

For the beekeeping brethren, no further warning is necessary. It appears, according to Dr. Hayes, that “the bees are trying to tell us something” and the question is, are we willing to listen?

“The last three years, people have just been pouring this chemical on crops and grass,” said Hackenburg, among the first American beekeepers to discover CCD in 2006. “Imidacloprid is approved for everything. All I’m saying is, you go buy this stuff at Wal-Mart to use on aphids or grubs or whatnot, and the little insert from the chemical company says straight out that it, one, makes bugs quit eating, and two, induces memory loss and confusion. Then, three, it gives them a nervous system disorder. And that’s exactly what’s happening to bees. I know many of the scientists refuse to go out on a limb and state emphatically that there’s a link here, but what about common sense? But then I’m just a dumb beekeeper who’s been beekeeping for 45 years. What do I know?”