13
Aug
“Biopesticides,” with Broad Definition, Challenged as Unsustainable
(Beyond Pesticides, August 13, 2021) Across the pond in the UK, two years of trials with spring and winter wheat varieties have shown, according to the Farmer Scientist Network (FSN), which conducted the study as Crop Health North, that so-called “biopesticides,” alone or in combination with conventional pesticides, can be useful in generating yield and grain quality comparable to those obtained through use of conventional “crop chemistry” (aka, synthetic chemical pesticides). According to Beyond Pesticides Executive Director Jay Feldman, biopesticides are a “mixed bag,” generally poorly understood, and defined differently by various entities and stakeholders. He notes that the term can be misleading and mixes contradictory approaches, adding that, “It’s troublesome when we continue to look for product replacements or substitutions for agricultural practices that are clearly ineffective, and in the process avoid the changes necessary to transition to organic practices,” which represent the real, long-term solution to the problems efforts such as these trials seek to remedy.
The project was sponsored and supported by the Yorkshire Agricultural Society (YAS) through the European Innovation Partnership (EIP-AGRI). YAS collaborated with universities, farmers, research institutes, agricultural organizations, and technology and food testing centers to conduct trials on three farms in the north of England. The wheat crops were monitored throughout their lifecycles, over the course of three harvests, to identify any diseases, and then manage them via chemicals, biological agents, or some combination of the two. The wheat varieties studied were spring varieties Willow and Mulika (in 2017); winter varieties Skyfall and Leeds (2018); and the winter wheat variety Sundance (in 2019).
The EIP-AGRI website notes, “The crops were analysed in terms of disease severity, yield and quality, looking specifically at whether the biological agents were as effective as the chemical compounds, and whether the new biological compounds work with existing agricultural practice. By using three independent sites, the project was also able to test performance on different soils and in varied climatic conditions.”
The project investigators cite the need to find alternatives to synthetic chemical pesticides not only because some of those are disappearing from the market, but also, because the concerns about pesticide use — for human health and environmental integrity — are real and growing, including among farmers. As asserted by YAS on its website and in a video it produced, there is growing worry in the agricultural community about the removal of pesticide products and their active ingredients from the marketplace. There is particular concern among farmers about how to address some fungal diseases that affect wheat; thus, the biopesticides used in the trial were biological alternatives to conventional fungicides. FSN notes that research into viable alternatives is limited and that these wheat trials aimed to address this dearth of information.
In the YAS video, James Standen, Farms Director for Newcastle University Farms, spoke of the importance of looking at “bioprotectant” products for use on wheat crops as farmers “lose active ingredients, with bans coming in for product safety, [and] the Precautionary Principle, and as resistance builds up to various chemicals.” Tom King, UK Regional Base Manager for Eurofins Agroscience Services, added (in the video) that bioprotectant products are most successful in an IPM (Integrated Pest Management) approach.
Essentially, as toxic chemicals are removed from the conventional agricultural toolkit, producers want other substances with which to treat agricultural pests, keeping the whole system in a perpetual “chase” for the next pest “fix,” whether chemical or biological. Apart from the toxicity and other “downstream” issues related to many synthetic control chemicals is the relentless issue of resistance — which all organisms will develop against harmful substances to which they are chronically exposed.
The study sought to compare the efficacy of biological controls (aka, biopesticides, bioprotectants, biologic products, biologic reagents) on disease resistance with that of conventional synthetic pesticides. But how do the investigating organizations define these products? According to Dr. Roma Gwynn, a bioprotectant specialist and director of Rationale (an organization of biopesticide strategists), “Bioprotectants (including microbial and botanical plant protection products) are substances that have been found in nature or derived from it, so they naturally break down and degrade very easily, and therefore you’re having a much lower impact on the environment and on non-target organisms.”
The U.S. Environmental Protection Agency (EPA) says, “Biopesticides are certain types of pesticides derived from such natural materials as animals, plants, bacteria, and certain minerals. . . . Biopesticides include naturally occurring substances that control pests (biochemical pesticides), microorganisms that control pests (microbial pesticides), and pesticidal substances produced by plants containing added genetic material (plant-incorporated protectants) or PIPs.”
Professor Rob Edwards, PhD, Head of Newcastle University’s School of Agriculture, Food and Rural Development and chair of FSN, writes of the “biologic products” used in the trials, “The biologic reagents are micro-organisms used to coat seeds before sowing or [to] spray onto the plant. They work, rather like probiotics in human medicine, to strengthen the plant’s natural resistance. These are relatively new to the UK but likely to become widely available over the next few years.”
Information on biopesticide active ingredients is available in the Pesticide Chemical Search database. (Enter an ingredient name and look under the Regulatory Actions tab for available information, and/or use the Filter by Pesticide Type link on the right side of the page to see a list of all biopesticides. From that list, access information about each ingredient.)
Recent research published in the journal plants calls biopesticides “natural, biologically occurring compounds that are used to control various agricultural pests infesting plants,” but also discusses “biocontrol agents composed of microorganisms including bacteria, cyanobacteria, and microalgae, plant-based compounds, and recently applied RNAi-based technology.” Those researchers identified multiple categories of biopesticides: microbial pesticides, biochemical pesticides, insect pheromones, plant-based extracts and essential oils, insect growth regulators, and GMO (genetically modified organism) products.
Some of those categories of biopesticides may well be compatible with organic agricultural practices, while others would not because they fail to meet the requirements of the National Organic Program, which operates within the U.S. Department of Agriculture (USDA). The USDA website explains that “Organic producers rely on natural substances and physical, mechanical, or biologically based farming methods.” Beyond Pesticides expects that there will be pressure to incorporate the use of biopesticides into the rules for organic production, and believes that could easily undermine the USDA Certified Organic brand and label if a fine-grained evaluation of each kind of biopesticide is not conducted before any such decisions.
Professor Edwards’s claim that the bioprotectants used in the subject trials work, like probiotics in human medicine, to strengthen plants’ natural disease resistance may be true. But this is not the MO of all biopesticides. For example, one category of bioprotectants uses, as noted above, “applied RNAi-based technology” to modify crop plants so they can “neutralize” pests. This is a genetically engineered (GE) technology that uses gene silencing — GE regulation of gene expression in a cell, as is employed in developing Roundup Ready seeds. This tinkering with gene expression is supposed to impact (lethally) target pests when they ingest the GE plant.
But there are significant, and largely unexplored, downsides to RNAi “biopesticides”; as researchers have identified, an “off-target effect is one of the major limitations associated [with] RNAi technology. Off-target effects are describe[d] as the silencing of non-target genes in the same organism or in non-target organisms.” As other scientists identified in the journal Bio-Science: “RNAi pesticide technology . . . produces those small ‘bits’ of genetic material. . . . [which] often have off-target binding elsewhere in a nontarget species’ genome that makes predicting toxic effects and designing maximum-hazard dose assays challenging for the wide range of species potentially exposed. . . . Knowledge gaps in the genomics and physiologies of highly exposed nontarget organisms currently preclude our ability to assess the activity spectrum of RNAi, determine whether toxicity assays will be sufficient in predicting the risks of RNAi-based crops, and explain how these risks may affect food webs associated with agroecosystems.”
In addition, little is known about the persistence of these genetic bits in the environment, nor what their impacts on ecosystems might be. There is something counterintuitive in labeling something a “bio” product (which connotes something “natural”) when in fact it involves genetic engineering — an entirely synthetic process.
Nevertheless, many researchers and agricultural organizations are very interested in the development of new, biopesticide substances or technologies that appear to be relatively “quick fixes” to the perceived problems of disappearing synthetic chemical pesticides and resistance to others. The UK entities involved in these wheat trials have indicated that the next step is to take the products that performed well in the study and figure out how to “optimize their use.”
Beyond Pesticides and other organic advocates recognize that some bioprotectant products may be ecologically sound and nontoxic; indeed, some fungi appear to hold great promise. But the fundamental quest ought not be one of seeking an endless stream of “substitute” products or controls as resistance to conventional pest controls continues to develop. Rather, the central and critical need is making the transition from conventional chemical farming to organic, regenerative agriculture — which involves shifts in both understanding and practices. That transition is the solution to the multiple threats of conventional pesticide use — harmful human health impacts, biodiversity collapse, the climate emergency, and environmental and ecosystem degradation. Development and adoption of GE and other dubious biopesticides represents functional “delay and diversion” from that necessary shift in how food is produced. See Beyond Pesticides Organic Agriculture page.
Sources: https://ec.europa.eu/eip/agriculture/en/news/inspirational-ideas-crop-health-and-pesticide and https://iapps2010.me/2021/08/03/uk-biopesticides-protect-wheat/
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
