Find Out How Farmers Are Killing Bugs—Without Chemicals

Biopesticides produced through liquid culture fermentation are a safe alternative.
A bioreactor that's being used to develop a fermentation processes for producing fungal biocontrol agents for field testing against weeds and insects. (Photo: Mark Jackson/Crop Bioprotection Research Unit/USDA-ARS-NCAUR)
Feb 21, 2013
A former Gourmet staffer, Lawrence enjoys writing about design, food, travel, and lots of other stuff.

Insects destroy millions of dollars worth of agricultural crops every year. While that’s bad news for farmers and consumers, many people are also uncomfortable with the widespread use of chemical pesticides.

Biopesticides—which are grown from fungi, insects, or other plants—could provide a solution to this delicate balancing act. However, due to the costs associated with the production of fungal spores, their price exceeds that of regular chemicals.

Traditionally, biopesticides are often grown on grains or other solids, but the USDA’s Agricultural Research Service (ARS) has come up with a process called liquid culture fermentation that can use less expensive sources such as soybean flour or cottonseed meal. 

“At ARS, we have scientists all over the country and many of them are looking to find natural enemies of insects, weeds, and plant diseases,” Mark Jackson, a microbiologist with the ARS Crop Bioprotection Research Unit in Peoria, Illinois, tells TakePart. “And when they find these organisms, one thing that has to be determined is if it is economical to mass produce them.”

Jackson’s speciality is microbial physiology and his approach has been to look at how liquid culture fermentation can be used to mass produce biological control agents. “In the case of microbial biocontrol agents like fungi, they still have to be living to be able to carry out their control mechanism,” says Jackson. “Because what happens is they actually infect and kill the weed or insect.”

“I’ve been working on this project since about 1989 and we work with our other researchers to not only determine how we can produce this economically, but whether it can be stabilized in a form that the farmer or homeowner can use,” he says.

The researchers use a bioreactor tank that Jackson says is similar to a fermentor, not unlike what’s used in the beverage/alcohol or pharmaceutical industries. “If you can produce it in a 100-gallon tank it’s pretty easy to move that up into a 1,000 or 10,000-gallon tank,” says Jackson. “The engineering has been developed for these other industries and, in terms of the harvesting of the cells, a lot of that technology is already engineered and available industrially. So from our standpoint the bioreactor offers the most economical approach.”

One form of the insect-killing fungi Jackson’s lab has tested is Isaria. “It produces a form in liquid culture that’s kind of like a yeast and so it’s something you can spray on insects,” says Jackson. “It turns out that these work very well in controlling a number of different soft-bodied insects.”

“The other form of the fungus, and this was sort of a novel discovery, is Metarhizium which can produce micro sclerotia, a kind of resistant form of the fungus,” he adds. “This opens a lot of doors to controlling insects that are in the soil and was a discovery that I think has a lot of potential in the future for producing a form of the fungus that can be used very easily in the soil or in aquatic environments.”

“It has properties that allow it to persist in the soil and remain viable and because of that it’s ideally suited to controlling insects in that environment,” says Jackson. “And there are a lot of soil-dwelling insects, from the white grubs that you have in your lawn to a number of agriculturally important grubs like corn root worms, wire worms, and many other very serious pests. Because we can scale up the process using the bioreactors, quantities can be produced that would be sufficient to satisfy the market demand for them.”

Jackson says that it’s difficult to predict how soon all this can happen due to EPA registration and a number of other issues, but he doesn’t think there will be a lot obstacles.

That’s very good news for our environment and those of us concerned with the use of chemical pesticides.

Do you think the government should commit more funding to the development of biopesticides?

Lawrence Karol is a writer and editor who lives with his dog, Mike. He is a former Gourmet staffer and enjoys writing about design, food, travel and lots of other stuff. @WriteEditDream | Email Lawrence |

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