A Closer Look at Naturally Occurring Pesticides

We talk quite a bit about the safety of pesticides and their federally regulated use by farmers to grow both conventional and organic produce. But we thought it would be a good idea take some time to dig deeper on how farmers use naturally occurring substances or biopesticides (biologicals) for pest control as part of their Integrated Pest Management (IPM) programs—a combination of techniques employed by farmers to ensure secured crop productivity and simultaneous environmentally sustainable pest reduction for conventional and organic crops.

These products have shown to be a handy and safe way for farmers to grow more of the great foods we enjoy. Similar to synthetic pesticides, the US Environmental Protection Agency (EPA) always conducts systematic scientific reviews to ensure that registered biological pesticides will not harm people or the environment. Interestingly, biologicals substances can be as simple as canola oil to more complex as microbial pesticides (some fungi can thwart weed and insects growth in crops—wow!).

To learn more about biologicals and explore advancements in this area of plant protection, we hunted down an expert in plant pathology, Barry J. Jacobsen, PhD, to ask more questions about biologicals and their positive impact on farming, food and our environment. Of note, Dr. Jacobsen helped to discover Bacillus mycoides isolate J (BmJ) the first biological pesticide that works exclusively by inducing plant resistance to diseases (including fungi and viruses). BmJ can be used in both conventional and organic crops and has been proven to help protect many fruit and vegetable crops.

Check out our Q&A with Dr. J below:

Food Insight Q: Can you tell us more about biopesticides and how they work?

Dr. Jacobsen’s A: “Biopesticides are products based on living organisms or metabolic products of organisms (plants, microbes, etc.) that suppress or control pests including, weeds, insects (and other arthropods) and plant pathogens (including bacteria, fungi, oomycetes, viruses and other microbes).

When I was teaching, a key statement in my lectures on biological control and biopesticides was, ‘biological control was the rule not the exception in nature.’ Plant pests are under continuous suppression by other organisms in their environment.

Biopesticides have many different modes of action. These include the production of toxic metabolites, production of substances that change plant physiology that directly or indirectly inhibits pest activity, parasitizing the pest population, production of substances that ‘tie-up’ key nutrients needed by the pest, by preemptively occupying infections sites.

In the case of Bacillus mycoides isolate J (BmJ), it activates the plant’s own genetically-based defense systems for pest protection. In general, plant defense systems work by directly attacking the pest, inhibiting pest feeding or reproduction, by limiting pest infection and establishment or by inhibiting or destroying key pest products required for infection or colonization. Most biopesticides work by multiple modes of action.”

Food Insight Q: Can you tell us more about what your research team does and how you support plant health?

Dr. Jacobsen’s A: “I have been interested in plant disease management using disease-resistant varieties of plants, pesticides, cultural management practices and biological controls for my entire 46-year career. My research program at Montana State University focused primarily on sugar beet and potato disease management using all available tools. In 1994, while working on management of Cercospora leaf spot of sugar beets, we observed some plants in a genetically uniform population that were relatively unaffected by this disease, while adjacent plants were nearly dead. I was interested in microorganisms that live on leaf surfaces and began a program to see if there were native Bacilli bacteria living on un-diseased leaves that might be helping these plants remain unaffected. I was interested in Bacilli because these bacteria produce endospores which allow their survival under harsh conditions and because many of the most successful biopesticide products are Bacilli. Development of a biopesticide for the Cercospora disease was important because there were no resistant sugar beet varieties and farmers were faced with increasing economic losses and fewer tools for control.

We isolated many Bacilli from leaves and characterized and tested them in the greenhouse for control of Cercospora. Of more than 350 Bacilli tested, two provided significant control with the best being Bacillus mycoides isolate J (BmJ). This started a 20-year research project that focused on the mode of action and optimizing use in the field and on use in integrated disease control programs on sugar beets, potatoes and other crops. Among our key findings, we found that BmJ would induce the host plant to “turn on” its own defense mechanisms involving a common plant gene called ‘NPR 1.’ Research demonstrated good to excellent control of diseases caused by bacteria, fungi and viruses on potato, cucurbit crops, tomato, pepper, pecan, banana and sugar beets.”

Food Insight Q: How can BmJ help agriculture now and in the future?

Dr. Jacobsen’s A: “BmJ is a new tool for growers to manage plant diseases. It offers a unique mode of action for use in combination with current fungicides to reduce the risk of pathogen resistance without exacerbating concerns about toxic pesticide residues or undesirable effects on farm workers or beneficial organisms like pollinators.

Because BmJ is Organic Materials Review Institute (OMRI) listed, it also offers a highly effective tool for use in organically grown crops, and it is also the only EPA labeled biopesticide that will control certain viruses. It is important to know that BmJ will not control all plant pathogens under all conditions and that it is best used in integrated management programs.”

Conclusion

The farmer's toolkit is diverse, plentiful and continues to grow. It’s pretty cool to think that there are bacteria that can help plants ward off deadly pests—natural protection from perhaps an unlikely source. Biopesticides allow farmers to continue to be agile and well-equipped as they aim to sustainably and safely grow reliable crops that support of food supply.

Here are the final thoughts from Dr. Jacobsen on what the future holds for BmJ: “I am excited to see that since we discovered the efficacy of BmJ and brought it to market, there has been the identification of many more disease-control applications on several crops not studied by my research program…. It is likely that the efficacy of this product will stimulate the development of new products that work with this same mode of action.”

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