Beyond Silent Spring
Dr. Jonathan Lundgren
May 19, 2022
Despite good intentions, integrated pest management was doomed to fail from its inception. The inherent problem with it is that insect pests are not an entomology problem. But integrated pest management treats them as though they are.
Prior to the 1940s, insect pests strongly influenced human culture. They decided where we lived on the planet (disease transmission), what we ate, when we decided to be outside, and they scurried their way into our vernacular (e.g., “bugs in the system”, “a lousy fellow”, etc). Synthetic pesticides changed all of that.
The discovery that organochlorines killed insects led to the rise of DDT and its kin, and we used it indiscriminately across the land and water. Insecticides were applied as an insurance policy against the possibility of pests, and corporations fed this misperception with great gain. Insect pests became resistant to the pesticides, necessitating more chemistries to be applied.
To reduce the rising use of insecticides and increase their longevity, the Integrated Control Concept was coined (in 1959 by Smith et al.). It established the concept of economic thresholds; insect pests only need to be treated when they exceed a certain population level. And this theoretically should have reduced insecticide inputs.
All of our chips were pushed onto the table. The powers that be decided that IPM was the way to manage a pest problem.
Fifty years later, arguably, the verdict is in. IPM did not deliver on its promises.
We now apply pesticides to more acreage than we ever have. Doses may be a little lower, but their impact is far greater because many of the chemistries are directly and indirectly more toxic to life than even the early organochlorines. They are marketed as things like genetically modified crops and seed treatments. These days, a big part of managing pests is all “in the bag”; insecticides are again used as an insurance policy against insects becoming a problem. Wildlife is declining; insects around the world are in decline; human health is deteriorating rapidly.
A central problem with IPM as it is practiced is that it assumes that pests are inevitable.
Farmers from around the world have taught me that pests are only a problem when your system doesn’t have enough diversity in it, and have too much uniform disturbance.
Insect pests aren’t an entomology problem. Insect pests are a soil problem. They are a problem of a system devoid of life. But most of all, insect pests are a cultural problem.
Recently, a paper by Tooker et al at Penn State revealed that cover crops were more effective than IPM and insecticidal seed treatments in managing pests using biological control on an experiment farm in Pennsylvania. This research is commendable; it adds fuel to the fire that cover crops are a viable tool for managing pests in this region. And Tooker and his team have had important voices in this space.
I think that an even more valuable contribution is that this study examines pest management on a bit more of a systems level. Cover crops and the biological control it supports are identified as the mechanisms behind why the cover crop system functions relative to the PPM and IPM systems. Our experience at Ecdysis Foundation is that this is only part of the story.
Cover crops and biological control only work on farms when they are embedded in an agro-ecosystem that fosters soil health and life. Indeed, they are a part of that system. But if we only focus on these two elements of the system, we will slip into the same hole we did with IPM.
Cover crops, along with no-till and abandonment of pesticides, do a lot more than increase the number of predators on a farm. Covers change the microclimate, making it more difficult for pests to grow. They increase the number of benign herbivores, potentially increasing competition with pests. They alter the physiology of the crop plant, potentially making the crop more resilient to pests. They alter the microbial community, potentially leading to altered symbioses that keep herbivores in check. Etc.
Our science is clear that plant diversity, cover, and minimal uniform disturbance to the soil are inherent in pest suppression. We make our pest problems when we sterilize our farms beyond recognition as ecosystems. We know regenerative food systems work, but we can’t always know all of the mechanisms for why.
In sum, the natural world is complex beyond our ability to understand it. Science is slowly catching up to the farmers that have created viable systems that are devoid of pests. Until then, science needs to take a back seat to faith.