Microbe-managing Mother Nature: From energy to E. coli, microbe management is big business

Recruiting microbes to do the dirty work

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Depending on the country, biopesticides can also let farmers skirt export restrictions. Some retailers, such as Marks & Spencer in the United Kingdom, even set limits on how much chemical residue can exist on food they buy.

"A farmer in Mexico or Chile knows they can use (them) and not get any problems," said Olav Messerschmidt, executive director of the Biopesticide Industry Alliance. "The growth has been good. A lot if it in North America has been because of organic farming. In Europe, there's more environmental consciousness."

Genetically modified foods can improve crop yields without noxious chemicals too, but they have come under fire from consumer groups. Although no one is known to have died from ingesting genetically modified organisms, corporations see them as a marketing negative.

Microbes, of course, can be dangerous to humans as well, but they tend to be safer than chemicals. One of the most popular biopesticides, Bacillus thuringiensis, kills insects by forming a protein crystal that the bugs ingest. The proteins rip through the innards of insects that go through a worm stage, Messerschmidt said, but humans and other mammals have acid-based digestive systems that aren't affected.

"We ingest it all the time," he said. "If you eat fruit with a little soil left on it, it's there."

Proponents assert that naturally occurring pesticides can have a longer life in the market than their chemical counterparts. Often, insects can build resistance to a chemical pesticide in about 20 generations, or three to five years. Many chemical insecticides no longer work in Costa Rica because of the near-constant spraying of bananas.

The microbes in biopesticides, however, emit an array of chemicals that act synergistically, which makes it tougher to develop resistance. Biopesticides can even be mixed with regular chemical pesticides to slow down resistance.

"It would take multiple mutations to overcome," Marrone said. "You can also rotate (biopesticides) with chemicals or mix it in the tank, for farmers that don't want to go cold turkey."

While bugs don't appear to resist the biopesticides, human resistance has prevented these materials from expanding. A couple of decades ago, large chemical companies such as Monsanto began to study the possibility of exploiting naturally occurring organisms, but many chose instead to put their energy behind genetic engineering.

Biopesticides have also faced regulatory barriers. In the 1980s, the Environmental Protection Agency wouldn't approve them for use.

In one celebrated instance, Professor Strobel, discoverer of Muscador, found a microbe for combating Dutch Elm disease. After he announced he would use it, the EPA sent six officers to his house and threatened to shut down the lab at Montana State. The New York Times ran a front-page story on his plight on the same day he was attending his son's college graduation. (Strobel's son now heads Yale University's molecular biophysics department and hunts microbes with him.)

"Talk about irony," he said.

Elsewhere in academia, biopesticides historically had not been accepted among many researchers, who played down their efficacy. But new testing procedures mandated by the EPA in the past two years have begun to show that biopesticides can perform as well or better than chemicals.

More importantly, farmers are buying into the concept.

"They will go with what works," Marrone said. "A farmer in Mexico told me, 'When I used chemicals, it is like the plant is on steroids. It gets pumped up, but then it poops out.'"