Biopesticides And Sustainable Ag
December 1, 2008 Most growers working to create a sustainable agriculture system understand that their first line of defense against unwanted pests is not found in the chemical shed. No, the first line of defense is the beneficial organisms — the good bugs — out in the field. That’s why a solid IPM program is one of the linchpins of sustainable agriculture. IPM combines cultural practices (i.e. safe planting dates), biological controls (i.e. predatory insects), and chemical control to keep pest populations low. But, when a pest problem becomes too severe and a chemical must be applied, the grower has two options: a traditional, synthetic product or a “softer” biopesticide.
Among the major benefits of incorporating biopesticides into a sustainable system is that they are generally more environmentally friendly and do not damage the soil, water supply, or the wildlife — including the beneficial insects.
“Their safety to beneficial organisms is one area where biopesticides definitely have a fit,” says Michael Braverman, manager, Biopesticide Program, IR-4 Project, Rutgers University.
Traditional chemicals can kill all the insects they come in contact with, while most biopesticides are insect and disease specific, controlling the unwanted pest while preserving the beneficial insects.
“Give nature a chance,” says Rex Dufour, a pest control advisor and California field director for the National Center for Appropriate Technology and the National Sustainable Agriculture Information Service.
“The beneficial organisms are just like livestock except they’re really tiny,” explains Dufour. “You wouldn’t expect to have a really good dairy herd out in the middle of the desert. These diverse groups of beneficial insects need good nesting habitat and, given half a chance, they’ll provide the services we need.”
In most cases, biopesticides are not meant to replace traditional products, but to be used in rotation, thus lowering the amount of synthetic chemical being applied. Over time, insects and diseases build resistance to synthetic chemicals, and by alternating synthetic chemicals with biopesticides, the efficacy of the synthetic chemical is extended.
Not Limited To Microbes
Unfortunately, when it comes to educating growers about this class of crop protection materials, the famous line from the movie classic “Cool Hand Luke” describes one problem: “What we’ve got here is failure to communicate.”
“Some people interpret biopesticides, often called biorationals, to be biological in a living sense,” explains Braverman. “They misinterpret the word and think biopesticides only encompass microorganisms like Bt (Bacillus thuringiensis) or some other microbial products. This tends to limit the scope.”
While the majority of registered active ingredients are microorganisms, biopesticides include an array of natural products including pheromones and kaolin clay.
Registration And Demonstration
According to Janet Andersen, director of EPA’s Biopesticides and Pollution Prevention Division, 997 biopesticide products have been registered since the division was formed — “at the request of the agrichemical industry” — in 1994.
One of the division’s key purposes is to help expedite the registration of biopesticides because they are viewed as more environmentally friendly than products formulated using traditional chemistry.
In addition to helping expedite registration, Andersen also points out that the division works with the IR-4 Project, co-funding demonstration projects to trial and showcase the efficacy of certain biopesticides. This is a component of the division’s Pesticide Environmental Stewardship Program to educate growers and promote the use of safer pesticides as part of a grower’s IPM program.
Braverman notes that a large number and a broad range of products have been trialed, and funded by the EPA/IR-4 grants. An example includes using fungus and bacterium-based products to control sclerotinia (lettuce drop) in Arizona lettuce.
More “Sustainable” Benefits
While the concept of sustainable agriculture was initially designed for smaller growers who supply local markets, many large growers are adopting similar practices for regulatory, economic, and environmental reasons.
In addition to the environmental benefits of biopesticides, Dufour points out two other factors that are becoming increasingly important to growers. Consumers are taking notice of where and how their fruits and vegetables are grown. “There’s a growing market for produce that is grown on farms that incorporate sustainable practices in their growing systems and farmers are aware of this,” he says.
Another key benefit has to do with regulatory issues, especially as they relate to water quality and runoff. Almost all biopesticides degrade quickly and have absolutely no detrimental effect on the water supply. “Let’s face it,” says Dufour, “Nobody’s monitoring for Bt in our water because it’s a naturally occurring organism.”