12
Feb
Eliminating Pesticides Increases Crop Yields, Debunking Myth of Pesticide Benefits
(Beyond Pesticides, February 12, 2021) Being many decades down the path of chemical-intensive agriculture, growers and other land managers (and all the industries that influence them) have come largely to ignore the efficacy of healthy, functioning natural systems to maintain ecological equilibrium, i.e., not letting any one pest or disease proliferate. Recent research points to an example of such ecosystem efficacy. The study, by researchers in California and China, sought to evaluate whether increased population densities of fungi might be suppressing nematode populations in California production fields frequently planted with the cole crops (such as brussels sprouts and broccoli) they favor. The research finds that a diverse population of fungi in soils is highly likely to be effectively killing nematodes that threaten such crops. This is not the first time Beyond Pesticides has covered the potential of fungi as an effective control for agricultural pests.
Thirty years ago, these nematodes were dealt with by application of soil fumigants and nematicides, because at sufficient population levels, the nematodes can destroy cole crops. During the following three decades, state-mandated monitoring showed that use of those chemical controls was diminishing and, by 2014, had been eliminated — even as yields rose. The co-authors point out that it is California’s relatively robust pesticide-use reporting program that surfaced information on the amounts of fumigants and nematicides used to control cyst nematodes since the early 1990s. The plummeting use of these compounds during that period suggested to the scientists a decline in nematode disease pressure, and prompted them to investigate why this unusual trajectory was happening.
The study evaluated nematode populations in 152 crop fields in 2016, finding that 62% of the soils harbored no detectable cyst nematodes, and only a few samples reached populations sufficient to cause any crop damage. The researchers used cyst nematodes as bait, and determined that broadly present hyperparasitic fungi were likely biologically suppressing the nematodes below a damaging level.
University of California-Riverside Department of Microbiology and Plant Pathology scientist and study co-author James Borneman, PhD commented, “The results from our baiting analysis combined with advanced molecular tools gave us a detailed depiction of the possible nematode-parasitizing fungi in these soils, which then provided a plausible explanation for this dramatic decrease in pesticide use.â€
The widespread availability of toxic pesticides makes possible the prevailing, chemical-intensive land management systems whose effects are broad and complex. Conventional agriculture spends copious time and billions of dollars ($9B in 2012, e.g.) on pesticide products, and countless more on labor to apply toxic chemical compounds to kill pests and “contain†diseases. These research results demonstrate how faulty the use of fungicides — which in 2012 amounted to 105 million pounds in the U.S — is likely to be. These compounds destroy fungi that provide a variety of beneficial and economically valuable ecosystem (and crop) services. Fungi decompose and recycle nutrients, improve moisture retention, and even act as biological controls for some fungal diseases. Many other pesticides, including glyphosate (which is an antibiotic) threaten microbial life, as well.
As Beyond Pesticides has written, “Microbial communities in the soil (and in other ecosystems) contribute to plant growth and health. In soils, those communities include bacteria, fungi, earthworms, and other invertebrates that break down organic matter and make nutrients available to plants. Bacteria and fungi engage in reciprocal exchanges of nutrients with plants, providing soluble forms of plant nutrients.â€
The subject research emphasizes the errant nature of chemically killing these organisms, and underscores a larger point: chemical-intensive farming and land management destroy these essential communities that, instead, could actually support and benefit growers. Organic farmers, landscapers, gardeners, and others responsible for managing land and landscapes, by contrast, feed soils and create favorable environments for the soil biota that make nutrients available to plants (primarily through decomposition), help suppress overpopulation, and provide other services.
Conventional agriculture has, for decades, treated soil as little more than an “empty matrix†into which inputs can be poured, and crops derived as “outputs.†Thus, growers will use, for example, soil fumigants — highly toxic gases injected or dripped into the soil to sterilize it. (These chemicals literally “empty†the soil of biotic communities.) Genetically engineered, or other, seeds are then planted; synthetic, petrochemical fertilizers are added to the soil; and soil, seeds, and plants are doused in pesticides and herbicides. From this, food is grown, harvested, and consumed. Something is very wrong with this approach.
Beyond Pesticides maintains that the solution to agricultural pest and weed problems is not the approach just described, which leads to an endless series of searches for the next chemical knock-down, which leads to resistance and the subsequent search for another pesticide, and another, and another. The solution is a system that takes land management out of this entropic pattern, which is the antithesis of regenerative, organic approaches that mimic and cooperate with natural systems, in which all parts must function well together for optimal results. In such systems, soil is respected and treated as a living ecosystem of components that, together, support and enhance biological life. A transition to such an approach is desperately needed.
The near-global dominance of chemical-intensive agriculture has had many impacts, not least of which is that food producers are, and/or feel, “locked in†economically to chemical management of pests and diseases. The science, public health, and advocacy communities are, more and more, teaching and persuading growers, landscape managers, legislators and policy makers, and the public — not only about the crisis of toxic pesticides (which impact human and ecosystem health, the food system, farmworker well-being, and biodiversity), but also, about the economics of organic, nontoxic approaches. Beyond understanding the threats of pesticides, some stakeholders are advocating for a revisioning of agriculture that embraces systems that cooperate with and support healthy, natural ecosystems and the services of which they are capable.
To go “meta†for just a moment: in 2014 Fred Kirschenmann, PhD, delivered a talk to Beyond Pesticides’ 32nd National Pesticide Forum. His remarks were excerpted in a Pesticides and You article, and this excerpt is worth revisiting: [Our current predicament] is “built on a prior notion coming out of the [E]nlightenment when we began to see ourselves as somehow being separate from nature — that we had not only a right, but a responsibility, as René Descartes put it, to become the masters and possessors of nature. We began to see ourselves as being somehow separate, not a part of what Aldo Leopold referred to as the ‘land community’ or the ‘biotic community.’ Our responsibility was to dominate it. [B]eing that we saw ourselves as separate from nature, we somehow saw ourselves as being sort of isolated. Therefore, what we did and also our conscience was oriented to our fellow humans. We take care of or care for them, to the extent that some of us want to do that for fellow humans, but that doesn’t extend to the rest of the biotic community because the humans are somehow special. . . . Aldo Leopold said one of the most important statements on ecological conscience: ‘A land ethic, then, reflects the existence of an ecological conscience, and this in turn reflects a conviction of individual responsibility for the health of the land. Health is the capacity of the land for self-renewal.’â€
Beyond Pesticides continues to work for the adoption of organic, regenerative agricultural and land management systems, which represent the safe and sane way forward out of the toxic quagmire in which farmers, landscapers, and others now operate. Please learn more and get engaged in this important effort. Beyond Pesticides stands ready to assist state and local efforts.
Source: https://apsjournals.apsnet.org/doi/10.1094/PHYTOFR-07-20-0009-R and https://phys.org/news/2021-02-ultimately-beneficial-fungi-effective-pesticides.html
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
