As growers seek to combat pest resistance, regulations on environmental and worker safety become more stringent and consumers demand safer and more sustainable products, biopesticides are enjoying an increasingly prominent role in crop protection programs.

In fact, they are the fastest growing category of crop inputs, and several large agrichemical companies have made investments through acquisitions and partnerships.

The evolution of biopesticides as a trusted and reliable tool in a grower’s toolbox would not have been possible without advances in science, technology and manufacturing processes that have, in many cases, made biopesticides as effective or more effective than chemical treatments, especially when used together in integrated pest management programs.

Most growers have heard the term biopesticides or biologicals, but may be unclear on their modes of action and when and how to use them successfully. Biopesticides are naturally occurring microorganisms (microbials– e.g., bacteria and fungi) and natural substances such as insect pheromones, fatty acids and some plant extracts, with a non-toxic mode of action.

They are well regulated by the Environmental Protection Agency in the Biopesticide, Pollution and Prevention Division. Not all things “natural” are safe, so the EPA has a process for ensuring that only the lowest risk products are registered as biopesticides.

The pipeline of new chemical pesticide active ingredients from the large agrichemical companies is small and very few new chemistries are being launched. It requires 10-12 years to bring a new chemical pesticide to market and costs close to $300 million. Hence, there will be a relative paucity of novel active ingredients in the next 10 years and beyond.

In contrast, more new biopesticide active ingredients are being registered every year, providing an exciting opportunity to fill the gap.

Biopesticides offer several key benefits that are driving their growth and adoption.

1. Resistance management – Most of today’s chemical pesticides are single site of action, working in one way on the pest, weed or plant pathogen. Therefore, pests can develop resistance quickly after repeated use. Biopesticides typically have novel and complex modes of action, which means that pests and pathogens are unlikely to develop resistance. As such, biopesticides can extend the life of chemical products when used in rotation or tank mixtures.

For example, fungicides have been used for several years in corn and soybeans for plant health. Researchers postulate that the increase in yields from fungicide use in corn and soybeans is due to control of undetected low levels of plant pathogens. Using a biopesticide in a tank mix with a chemical fungicide can increase yields even more, stopping the development of resistance and synergizing the chemical mode of action.

Marrone Bio Innovations has several years of field trial and grower use data with a biofungicide (extract of giant knotweed) added to a chemical fungicide (together in the tank or applied earlier in the season), which boosted yields by approximately five bushels per acre in corn and two in soybeans. Another example involves seed treatments.

There are reports that pests are developing resistance to seed treatments containing neonicotinoid chemistry (note: this chemistry is controversial for its effect on pollinators and has been restricted in Canada and banned in Europe). Adding a biopesticide as a component in a seed treatment can manage resistance and increase crop yields.

Indeed, there are several examples on corn and soybeans. Unique strains and species of bacteria coated on the seed with chemical insecticides and fungicides (Bayer, Syngenta, Valent, Albaugh/Marrone Bio) showed increased yields compared to chemical-only seed treatments.

Our company is developing a bioherbicide that controls glyphosate and other herbicide-resistant palmer amaranth. In our tests, the combination of the chemical with the natural herbicidal compounds produced by our new species of bacteria broke the resistance, resulting in effective control.

2. Synergy with chemical treatments – As part of an IPM program, biopesticides can increase the efficiency of chemical treatments, as described above. The different modes of action result in better control than either alone.

Typically, biopesticide field trials conducted by consultants or university researchers compare a biological standalone to the best chemical treatments, which may include tank mixes. If the standalone biological is not as effective as the chemical(s), often the work stops there and the results reported, “the biological did not work as well as the chemical(s).”

It is critical to integrate the biological into the program and not just assess them standalone. Very often, the IPM program results in marketable yields and quality can exceed chemical-only programs.

However, even if the results are the same as the chemical-only program, the IPM program is enhanced with the ability to manage residues, delay resistance, increase labor flexibility and enhance beneficials.

The key to maximizing the performance of biopesticides and IPM programs is to understand the modes of action of the biological compared to the chemical. Best use is understanding how they work, rather than asking, “do they work?” Many biopesticides are slower acting than chemicals and can take several days to see pest mortality. Some stop feeding, reduce reproduction and inhibit molting.

Counting just pest mortality rather than measuring crop damage, yields or season-long population suppression may mask the overall benefits to the program. Biofungicide use in an IPM program can often result in increased marketable yields while overall percent disease control is less than the chemicals in standalone trials.

3. Managing residues – Increasing restrictions on chemical residues, particularly for exported crops, make biopesticides an attractive choice for pest management. Biopesticides are exempt from residue tolerances and global Codex Maximum Residue Levels, and can be used right up to harvest. If there is a late pest or plant disease that shows up, a chemical may not be an option if the residue or the specific level is not allowed by grain buyers.

4. Safety – Biopesticides generally affect only the target pests or plant pathogens and pose little to no risk to birds, fish, beneficial insects, pollinators, mammals and other non-target organisms. They also pose minimal risk to worker health and do not pollute air or water. Biopesticides are biodegradable and break down quickly in the environment.

Most biopesticides can be applied with the lowest level of personal protection equipment and typically do not require special permitting and large buffer zones.

5. Labor flexibility – Increase worker and grower productivity and reduce labor costs by allowing faster re-entry times. Biopesticides have short worker re-entry times, typically four hours, the shortest interval permitted by law. This allows for spraying in the morning and resuming a normal work schedule in the afternoon.

6. Organic production – Biopesticides are often seen as “organic-only” products. However, 70 percent of biopesticides are used by conventional growers. Consumer demand for organic food exceeds supply, and organic food is the highest growth food segment. There is a shortage of organic corn and soy acres to meet that demand, and growers typically can make more money per acre with organic commodities.

However, organic grain acres are still a very small as a percent of the total acres so using biopesticides in conventional production will reap the benefits described above.

Advances in biopesticides have significantly improved existing products in performance, formulation, ease of use, shelf life and spectrum. In the coming years, the role of biopesticides will evolve from that of an additional tool for pest management to the foundation of pest management programs.

Whether used alone but especially in combination, biopesticides improve grower profitability, promote plant health, control unwanted pests and plant diseases, ensure food quality, and make a healthy contribution to feeding an ever-growing population that demands sustainability.

So where are growers and their consultants to look for information? The innovations in biopesticides are continuing at a rapid pace. The Bioproducts Industry Alliance is a trade group with hundreds of member companies and information about the category.

By Pam Marrone, CEO and Founder, Marrone Bio Innovations Inc.  Pam is pictured above, field-checking the efficacy of one of her biopesticides.

Above: Isolates in the Marrone Bio Innovations lab.