The Bug Farm

Ron Whitehurst, PCA and owner Rincon-Vitova Insectaries, Inc.

“Working with these species in a bio-diverse agroecosystem will require specific training and the ability to evaluate the pest-crop-beneficial input dynamic in very diverse locations. Biological control is a cornerstone of IPM.” – Entomologist Lynn LeBeck, Executive Director, Association of Natural Biocontrol Producers 

In biodiversity-based farming systems, also referred to as regenerative organic, farmers reduce inputs and increase profit through building soil and plant health and increasing biodiversity. Sustainable Pest Management (SPM) recognizes that successfully transitioned regenerative organic farms have few pest problems and little or no pesticide use. This is because natural control is achieved by the presence of a pests’ natural enemies maintaining a proportionately high ratio. To support the transition to regenerative organic farming, monitoring and interventions related to biological control is a major field for Research and Extension investment along with development of new effective biopesticides for the Roadmap to achieve its goals. For six decades the centrality of biological control has been understood by leaders of thought about pest management.

In this article we survey contributions to the history of Integrated Pest Management (IPM) to understand why it has not prevented pest infestations, nor reduced the number of new pesticides or the level of their use, and explore what needs to be different when using Sustainable Pest Management (SPM).

1946 EVERETT DIETRICK AND IPM’S FORERUNNER “SUPERVISED CONTROL”  

My mentor, Deke, met Prof Harry Smith and his cadre of biocontrol entomologists when he want to graduate school at UC Berkeley on the GI bill after serving in the Coast Guard in the Pacific Theater. He appreciates Richard Doutt for directing him to the biocontrol team. Deke left Berkeley for a job at the University of California Citrus Research Station and after 12 years doing field research in many crops, he left the university because there was no more funding to do biological control research. He wrote, 

“UC Farm Advisors and county agents in addition to the UC researchers in the Department of Entomology were particularly supportive of pesticides.  Only a very few would carry on a dialog about integrated control and least of all IPM.  Their mantra was to apply pesticides whenever what was left of the natural biological control failed and of course it failed when broad spectrum chemicals were applied.  Integrated control was monitoring and spraying every time the economic threshold was reached.” [Unpublished memoirs]

He built a business mass-producing beneficial insects and selling a service to farmers that he called “Supervised Control”. Deke’s insights and enthusiasm convinced farmers in the Imperial and Coachella Valleys to stop calendar DDT spraying of cotton by selling egg parasitoid wasps (Trichogramma) for cotton bollworm.  Having learned during twelve years with the University of California Department of Biological Control surveying insect ecology on “untreated” farms  in the years prior to “organic”,  his business expanded with a dozen Supervised Control consultants using applied biological control instead of pesticides, successfully persuading farmers of the method’s effectiveness.  

During such conversations with farmers, he often listened for the moment when a farmer was visualizing the interaction of the problem pest and the “natural enemy complex” on his or her farm, as the farmer would eventually ask a question about how the insect ecology worked if you introduced natural enemies. Deke would say, “Food drives all these systems.” As that understanding sank in, the farmer stopped being fearful and began to show curiosity about how to observe insect ecology. Once he or she recognized that both monitoring information and consideration of alternative actions focused on conserving natural enemies, the farmer rarely ever resorted to chemical pesticides again. These are the same principles, features, and pedagogy that direct our company Rincon-Vitova Insectaries today.

1959 PUBLICATION OF “THE INTEGRATED CONTROL CONCEPT”

In a 50th anniversary commemoration of what is considered the “most important” pest control paper of the 20th century, a 2009 article in California Agriculture recognizes the scientists behind the framework that became Integrated Pest Management. The 20-page paper explains the damage from pesticides and proposes the consideration of multiple methods that would be more effective and better protect farmworkers and the environment. The commemorative article summarizes IPM principles without giving full credit to their development in the work of field researchers like Everett Dietrick who developed the applied insect ecology strategies first called “Supervised Control”:

• Recognition that agriculture is part of a larger ecosystem, comprised of all the living organisms of an area and their environment.
• Supervision of insect levels so that chemical applications take place only when and where they are absolutely necessary.
• Promotion of beneficial insects through conservation and augmentation.
• Use of products and application timing to target specific pests, minimizing the effect of treatment on pests’ natural enemies.

Authors of the visionary article, Vernon M. Stern, Ray F. Smith, Robert van den Bosch and Kenneth S. Hagen, are now called ‘the fathers of IPM’. However, Deke would say that the concepts came out of the preceding decade of development of Supervised Control by the larger team of field researchers and consultants. Vern Stern’s primary contribution was that he recognized the collective visionary insights of those around him and led in writing them down.

LICENSING OF PEST CONTROL ADVISORS (PCAS) IN CALIFORNIA

Deke recalled passing the exam in all categories in 1974. He wrote, 

“There was nothing written or questions asked about the ecological basis of pest management and natural biological control. It seems that IPM is all about chemicals and mortality from these powerful pesticides and not about beneficial insects and the interference of the pesticide applications to the work of these biological control organisms. Applied biological control organisms were not covered, nor was there anything suggesting that natural enemies are destroyed in a blowback and resurgence of pests following a pesticide application.” [Unpublished memoirs]

1986 ECOLOGICAL THEORY AND INTEGRATED PEST MANAGEMENT PRACTICE, ed Marcos Kogan

Clara Nichols and Miguel Altieri in their book chapter entitled “Agroecology: contributions towards a renewed ecological foundation for pest management”, explain the theoretical principles about transition in a farming system framework. They state that the desirable attributes of stability and resource conservation “are connected to the higher levels of functional biodiversity associated with complex farming systems.”  It is clear, they say (referring to Southwood and Way, 1970) that insect population stability depends on “the actual density-dependence nature of the trophic levels”, not just on trophic diversity, specifically on who eats who.

“In other words, stability will depend on the precision of the response of any particular trophic link to an increase in the population at a lower level.” 

They also had this to say about biodiversity-based farming systems: 

“Diverse systems encourage complex food webs which entail more potential connections and interactions among members, and many alternative paths of energy and material flow through it. For this and other reasons a more complex community exhibits more stable production and less fluctuations in the numbers of undesirable organisms.”

1994 INTEGRATED PEST MANAGEMENT: THE PATH OF A PARADIGM by James R. Cate and Maureen Kuwano Hinkle. Excerpts from recommendations, pages 30-33:

• The first need is…a clearly articulated definition of IPM that goes beyond use of monitoring and economic thresholds restoring the ecological basis of IPM.
• Regulatory incentives can encourage the development and registration of biological alternative products.
• Pest management should be directed at developing solutions that provide durable, long-term controls [by] a systematic assessment of key pests and the nature of the ecological upset or imbalance that has caused a pest problem.
• Funding of programs needs to be maintained over a decade or more and implementation projects often require three to six-year commitments. 
• Funding needs to be allocated in a way that avoids agency competition, turf disputes, and conflicting purposes [in a] competitive grants program of basic research, mission-oriented research, and implementation grants…
• Adoption by farmers…is best accomplished by having the users be active participants in the development and implementation teams….A team building structure would help to diffuse technological advances quickly and establish a social and cultural receptivity to continued practice and improvement of IPM…
• The advice should not be influenced by the commercial need to generate sales of specific products. 
• Inducements could be in the form of crop risk insurance for users and private crop consultants and in the form of IPM program development incentives to users, particularly during the transitional periods when growers are moving to ecologically based management from chemically based management.
• Inducements could also be in the form of predictive models and information that can be used by consultants and users to forecast pest population models and seasonal growth of crops, pest populations, and populations of biological control agents. 
• Pest management cooperatives could be encouraged with incentives to assist farmers and neighbors in addressing pest problems in area-wide and systematic ways.
• Building on the scientific principles that support an ecologically based IPM, and the original concepts of Integrated Control, IPM is a useful organizing principle around which utilization of all technologies can be integrated—biological controls, host resistance to pests, biotechnology, alteration of the cropping system, etc.— to facilitate natural controls or antagonists of the pest or to create a more unfavorable environment for the pest. By focusing on the basic causes… and appropriately addressing different types of pests, we can manage pest populations so they no longer damage crops, goods and human health.

1996 NAS: EBPM

National Academy of Science report (1996), Ecologically Based Pest Management (EBPM) stated that EBPM “should be based on a broad knowledge of the agro-ecosystem and will seek to manage rather than eliminate pests” in ways that are “profitable, safe, and durable.” Its vision was the transition of agriculture to a total-system approach in an agroecological framework.

1997 NAS: TOTAL SYSTEM APPROACH TO SPM 

National Academy of Science (1997) Proceedings paper, “A Total System Approach to Sustainable Pest Management,” went further in calling for “a fundamental shift to a total-system approach for crop protection [which] is urgently needed to resolve escalatory economic and environmental consequences of combating agricultural pests.”  Successful transition to SPM operates in the context of the type of farming system in which one is working. In the context of a new Roadmap for Sustainable Pest Management, we need to be unambiguous about which “system” we are referring to.

2005 SARE GUIDE TO ECOLOGICAL STRATEGIES

As plants developed inherent protective mechanisms against pests, they were assisted by numerous partners in the ecosystem, including:

A total-system approach was then well described in Sustainable Agriculture Research and Education (SARE) Handbook 7, Manage Insects on Your Farm – A Guide to Ecological Strategies (2005) by Miguel A. Altieri and Clara I. Nicholls with Marlene A. Fritz. They wrote that EBPM (EPM for short)

employs tactics that have existed in natural ecosystems for thousands of years. Since the beginning of agriculture— indeed, long before then — plants co-evolved with pests and with the natural enemies of those pests. 

• Beneficial insects that attack crop-eating insects and mites by chewing them up or sucking out their juices
• Beneficial parasites, which commandeer pests for habitat or food
• Disease-causing organisms, including fungi, bacteria, viruses, protozoa and nematodes, that fatally sicken insects or keep them from feeding or reproducing. These types of organisms also attack weeds.
• Insects such as ground beetles that consume weed seeds
• Beneficial fungi and bacteria that inhabit root surfaces, blocking attack by disease organisms” [page 2]  

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2021 “THE FUTURE OF ORGANIC INSECT PEST MANAGEMENT: BE A BETTER ENTOMOLOGIST OR PAY FOR SOMEONE WHO IS”, by David Headrick

As he explains in this paper, David Headrick, Professor of IPM and Biological Control at Cal Poly SLO, trains PCAs and sees them as a critical link in the transfer of knowledge and skills to the growers for site-specific problem-solving, toward a goal of diverse cropping systems. He also explains that the California State Universities (CSUs) are the primary educational institutions training future PCAs.  So, the CSUs must be included in the discussion regarding implementation. 

Dr. Headrick sees a continuum from chemical-reliant systems to biological-dependent systems, but he supports the framework we have adopted of a continuum of three basic types of farming systems: chemical input-based, biological input-based and biodiversity-based.

There may currently be more progress in other parts of the world where public investments are addressing the climate crisis. INRA, the French National Institute for Agricultural Research, began publishing papers in 2015 about a framework for study of farms in transition. Beginning in 2020, it merged with IRSTEA, the French National Research Institute of Science and Technology for the Environment and Agriculture to form INRAE, the French National Research Institute for Agriculture, Food and Environment, creating a critical research mass and pooling of labs and observatories, technical platforms, data repositories, etc. making it uniquely able to perform valuable research on the preservation and restoration of biodiversity and risk anticipation and management, as well as regional agricultural strategies, water resources, digital agriculture, and more. 

The INRA, now INRAE, framework for characterizing farming systems informs the following discussion:

CHEMICAL INPUT-BASED FARMING SYSTEMS

Deke called these systems Conventional Chemical Control (CCC) to distinguish them from Biological Control by Natural Enemies (BC by NE) systems. He often described very different interventions in such systems belonging to neighbors or family members growing the same crops. “Both are right”, he said, “because what works in a BC by NE system won’t work in a CCC system.” 

At one end of the spectrum are chemical input-based systems under eradication programs for invasive species. Since the pest is usually eventually declared established and the state can no longer conduct area-wide eradication, as Dr. David Headrick explains to his Plant Protection students, “Then it’s biological control to the rescue for a long-term solution to avoid economic losses and having to use insecticides.” This leads to a discussion of the problem of pesticide resistance and how to manage that by alternating pesticides with different modes of action. Since their inception, bio-control entomologists have advocated against total eradication programs, because they practically never succeed and the spraying is highly disruptive. 

Another characteristic of chemical input-based farming systems is the degree to which they are embedded in globalized commodity-based food systems that favor large growers and distributors far removed from consumers and end-users. This allows producers to be invisible and thus less accountable for negative health and ecosystem impacts. The Roadmap toward SPM is timely because opposition to the resulting pollution and lack of accountability is steadily growing. 

BIOLOGICAL INPUT-BASED VERSUS BIODIVERSITY-BASED FARMING SYSTEMS

Distinguishing between biological input-based and biodiversity-based farming systems in the pest management transition continuum is increasingly important. Differences lie not only in the relationship between biodiversity and biological control of pests described above.  We now have insights that increasing biodiversity is correlated with accelerated timelines and community tipping points when sufficient multiple species are growing together. Beneficial increases in measures of soil health, carbon sequestration, plant fertility, pest resistance, water penetration and water-holding capacity, and resilience to climate impacts all result.  Past understandings of risk to benefit ratios and economics are shifting toward a wider scope of valuable characteristics not always found on typical organic farms that are biological input-based systems. 

Biological input-based systems (most organic acreage in California) are still usually relatively simple systems and not evolved to provide much in the way of the above-described biodiversity benefits compared to what is experienced in regenerative farming systems that build on the best practices for soil aeration, hydration, protection and fertility with well-developed and conserved soil microbial biodiversity and habitat enhancements for natural enemies.  Biological input-based farming systems are a middle area of the continuum between chemical inputs and biodiversity-based systems that have more complexity and more resilience with fewer inputs.

The “efficiency/substitution” paradigm analyzed by INRAE scientists, especially when it prioritizes “alternatives” without the end-goal of biodiversity, limits the language and patterns of thinking in contrast to a more biodiversity-based paradigm for transition. Successful consultants in regenerative agriculture within our network quickly recognize the limiting belief that soft chemical or biopesticides are essential for SPM.  Experts holding the paradigm of “efficiency/substitution” are understandably averse to setting goals for transition to organic, because from a farming system perspective it is far from perfect with some strict prohibitions that are not pragmatic. 

However, there is no doubt that the organic label from a policy and economic perspective will drive adoption of SPM. The federal government is investing in transition to organic and the state must do so as well by removing all fees and inspection costs, by providing a full day of expert consultation toward an Organic Farm Plan, and by requiring the public kitchens purpose increasing percentages of local organic products. Organic farming systems are not the objective, but rather a stepping-stone on the path to regenerative biodiversity-based farming systems. The marketing value of the organic label cannot be squandered. It is the ideal metric for incentivizing accelerated soil carbon sequestration and advancing SPM. Buyers can be educated and also in some cases required by their institutions to seek out those inquisitive, determined, pioneering organic farmers that have at least begun to care for the soil and wildlife, have stopped toxic chemical inputs, and are on the path to profitable biodiversity-based farming systems. 

Hence, the SPM Roadmap must feature the recognized co-benefits of biodiversity PLUS the following: 

1. Biodiversity-based systems offer long-term success that is unlikely when “alternatives” and substitution of soft chemical and biopesticides are disproportionately spotlighted in the middle part of the farming system continuum. 
2. The organic label is the most powerful metric to drive consumer investment and rapidly scale transition regardless of the scientific rationale of the standards or the net value to farmers of inputs and practices. If there are anomalies or absurdities in the Organic Standard, they can be fixed while focusing investment in transition to organic. 
3. Regenerative organic agriculture is trending and is powerful in featuring incentives beyond the basic organic label, because of its focus on soil carbon and potential carbon or eco-credits, not to mention it providing the greatest economic and ecological resilience or the farmer. 

BEWARE OF ‘ALTERNATIVES’

We don’t want alternatives. We want to do what is actually most effective for the long term. The limiting paradigm of “efficiency/substitution”-based agriculture and the limits of a “sustainable agriculture” framework are discussed in two papers from the preeminent research team at INRA [Duru et.al. 2015; Therond, et.al. 2017]. In the Duru paper the limiting aspect of the “efficiency/substitution paradigm” relative to the “biodiversity paradigm” is discussed. Framing transition in an “alternative or substitution mindset” will increasingly limit capacity to do what is most effective in the long-term. “Substitution thinking”, in fact, has already led to unfarmable land because of climate impacts. That is just the beginning of the difficulties that lie ahead.

“Efficiency/substitution” farming systems are often held up as “Best Management Practices” in a hierarchy of recommendations in UC-IPM publications with conventional chemical control presented FIRST and biological control presented as a chemical substitution or alternative. As such, the University of California imposes a top-down hierarchy of upside-down guidelines resulting from partnering with the companies selling patented products for profit.  The aim of these companies, and the researchers funded by them, is increasing efficiency and reducing costs and pollution by comparing a lower-risk alternative with a chemical control in a chemical input-dependent farming system test plot. Where is the biodiversity-based control?

At the meetings where Pest Control Advisor’s pay to receive Continuing Education Units, they generally hear product representatives and Farm Advisors sharing new information about which product killed more pests and what additional crops a pesticide produce label now covers. There is nothing on a chemical label about approved use of a product on a farm in transition away from being chemical input-based, such as potentially spot spraying based on a modified action level. Experts teach that their findings are uniformly applicable across all farms. By contrast, what if there were CEUs given for PCAs to learn how to recognize or build a biodiverse, problem-free system anticipating no need for alternatives to chemical pesticides?

I made a proposal recently to talk about biological control and cover crops that was rejected by DPR for CEUs. Our General Manager with nearly two decades of experience helping customers manage pests biologically was required to take twelve hours of courses in production farming and IPM centered around pesticide laws and regulations. She can now take the PCA exam and little to no questions will reveal the depth of her knowledge about SPM. The current dominance of the “efficiency/substitution” paradigm needs to change.  The pendulum seems to swing back and forth regarding acceptance of CEU’s for ecological approaches.

Farmers who demand urgent availability of “alternative” products before agreeing to consider changes in their practices are seriously hurting themselves. Climate impacts and particularly water shortages will teach them that they should have prioritized transition and said goodbye to pest management tools that hold them back.  The Roadmap should nowhere even faintly suggest that “alternative” inputs are the end-goal for SPM when we know that durable transition is attainable by increasing above- and below-ground biodiversity with its co-benefits, including low incidence of pest problems. 

In the words of Dr. Annemiek Schilder, Director of the Ventura County University of California Cooperative Extension office, 

“In the end, it is all about increasing biodiversity across the system, from the soil and roots to above-ground plant parts to the landscape and region, to increase efficacy and resiliency/robustness of the agroecosystem. There is a lot we don’t know, especially how soil health affects plant health….Within this, there needs to be a focus on understanding ecological principles, interactions and population dynamics of beneficial and pest species, as well as the role of and how to measure farm biodiversity. Also, is all biodiversity good or do we need specific components for a pest/disease-suppressive system?”

Dr. David Headrick, Entomology Professor at Cal Poly San Luis Obispo also encourages research that helps discriminate about how to diversify the cropping pattern: 

“In thinking about the tactic of diversifying the farmscape, I hope that the SPM workgroup can appreciate and acknowledge that diversification of an agroecosystem occurs on a spectrum.  On one end of the spectrum you can have the addition of a single plant to a monocrop; on the other end of the spectrum you can have hedgerows and insectary plantings in a polyculture farmscape.  It would be wrong not to acknowledge the efforts of current growers in Salinas in diversification.  Twenty years ago, the standard method for aphid control in row crops was an early application of Metasystox-R, an extremely dangerous systemic organo-phosphate.  But now many of them plant sweet alyssum to attract syrphid fly predators and get excellent control of aphids. This is thanks to the work of Eric Brennen with the USDA-ARS at his organic research farm in Salinas, and others.  By adding one additional plant – increasing the diversity of the cropping system – they have an excellent tool that invokes the natural aphid control provided by naturally occurring syrphid flies.”  

“So, on one end of the spectrum, we can have a single plant increasing the diversity of a monocrop that eliminates the need for one of the worst insecticides.  To me that is remarkable, worthy of note and is a significant step on the Roadmap toward Sustainable Pest Management and should be acknowledged as such.  This example also shows the successful collaboration of the research and grower communities.  At first, the alyssum was planted in several rows throughout the field, but growers were concerned about reduced productivity.  Dr. Eric Brennan, USDA/ARS Research Horticulturist and specialist in organic and climate-smart farming in Salinas, has been extending research done by Bugg et. al. (2008) showing that alyssum plants could be placed randomly in the fields at much reduced numbers and still maintain excellent aphid control without compromising productivity.”

The guiding principle that lifts SPM beyond IPM is that natural control is the end goal for successful transition. To help understand why this is so, we need to understand how living organisms communicate with each other in diversified agroecosystems. The interconnectedness has never been much of a feature in the practice of IPM. Nature exercises forces that must be part of the SPM knowledge base. The glimmer of knowledge available about heterospecific and conspecific communication in soil and above-ground food webs helps us appreciate pure entomological research AND respect intuitive ways of knowing. Our ignorance about natural phenomena is boundless compared to the tiny, usually biased glimmer we get from peer reviewed papers. 

For example, underlying plant-insect communication, we now know that by monitoring soil and especially also plant sap, practitioners can assess a plant’s health and capacity to resist pests. We can develop biological action levels for customized foliar nutrient and biostimulant sprays or side-dressings that shift the bioavailability of key nutrients to enhance plant defense mechanisms. Dr. Phillip A. Callahan spent decades researching and reporting on these phenomena showing that a healthy plant emits molecules and low energy electromagnetic waves that essentially repel pests while unhealthy, nutritionally out-of-balance plants attract pests. Dr. Tom Dykstra, a student of Dr. Callahan, founded a lab to continue this study and its application in agriculture.  

As I discussed in Part 6: “New knowledge for pest prevention” other research shows that molecules emitted by healthy plants continue for up to five days to protect neighboring plants [Sharma, et. al 2017]. Healthy plants can detect certain terpenoid molecules that cause an influx of calcium ions and membrane depolarization that can impact an herbivorous insect’s chewing ability.  It requires a lively soil biology for plants to access the calcium, sulfur and other minerals that are there in the soil and have such a widespread effect on the entire ecology including insect physiology. 

Moreover, complex plant communities of at least eight species support each other in the root zone to bump up nutrient cycling and fertility. Arbuscular mycorrhizal fungi around plant roots stimulate systemic tritrophic interactions in the soil ecology. Plants living in such lively root systems emit molecules that consistently direct insect behavior. For example,

“All plants synthesize a suite of several hundred terpenoid compounds with roles that include phytohormones, protein modification reagents, anti-oxidants, and more. Different plant lineages also synthesize hundreds of distinct terpenoids, with the total number of such specialized plant terpenoids estimated in the scores of thousands. Phylogenetically restricted terpenoids are implicated in defense or in the attraction of beneficial organisms.” [Pichersky and  Raguso, 2017].

These molecular and bioelectromagnetic phenomena of living ecosystems are important for carbon farming as well as the SPM knowledge base.

The implications of the complexity in biodiversity-based systems seem miraculous. It is a challenge to measure or model the complexity that should characterize living ecosystems. It is generally not a straight-line linear correlation between diversity and systemic functionality such as where tipping points of biodiversity accelerate all healthful functions in the plant, including the amount of deposition of soil organic carbon, nitrogen availability, and molecules involved in defense mechanisms. This hyphal/molecular/bioenergetic/epigenetic world is the boundary where SPM can leave IPM behind.

Board Certified in multiple entomology specialties, my mentor Everett Dietrick studied the scientific literature, attended and sometimes presented at top scientific conferences, and maintained close communication with researchers around the world, but he frequently said that his own repeated observations were equally applicable compared to the knowledge base available in the scientific community. From decades of sweeping with a standard sweepnet and the D-Vac Vacuum Insect Net that he co-invented, his comprehensive monitoring of a field in the farmscape context often yielded exceptional intuitive insights about population dynamics and strategies to tip the balance in favor of natural enemies. Strong training to develop deep curiosity about relationships in the natural world and personal capacity for other ways of knowing will make SPM more successful than IPM in pesticide use reduction. 

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Altieri, Miguel A. and Clara I. Nicholls with Marlene A. Fritz. Handbook 7, Manage Insects on Your Farm – A Guide to Ecological Strategies. Sustainable Agriculture Research and Education (SARE), 2005. 

Bugg R.L., R.G. Colfer, W.E. Chaney, H.A. Smith, J. Cannon. 2008. Flower flies (Syrphidae) and other biological control agents for aphids in vegetable crops, University of California, Division of Agriculture and Natural Resources.

Callahan, Phillip (1965-1975). 36 published papers summarized on The Free Library page “Electromagnetic communication and olfaction in insects”.

Duru, M., Therond, O., Martin, G. et al. How to implement biodiversity-based agriculture to enhance ecosystem services: a review. Agron. Sustain. Dev. 35, 1259–1281 (2015). https://doi.org/10.1007/s13593-015-0306-1

Dykstra, T. How Insect Pests Identify Unhealthy Plants. Regenerative Agriculture Podcast with John Kempf. 

Headrick, David. The Future of Organic Insect Pest Management: Be a Better Entomologist or Pay for Someone Who Is, Insects 2021, 12(2), 140; https://doi.org/10.3390/insects12020140

Nichols, Clara and Miguel Altieri, “Agroecology: contributions towards a renewed ecological foundation for pest management” in Ecological Theory and Integrated Pest Management Practice, ed Marcos Kogan, 1986.

Cate, James R. and Maureen Kuwano Hinkle, Integrated Pest Management: The Path of a Paradigm. Audubon Society, 1994.

National Academy of Science-National Research Council, Ecologically Based Pest Management (EBPM)-New Solutions for a New Century, 1996.

Pichersky, Eran and Robert A. Raguso, Why do plants produce so many terpenoid compounds? New Phytol 2018 Nov;220(3):692-702. doi: 10.1111/nph.14178.

Sharma, E., Anand G., & Kapoor, R. (2017). Terpenoids in plant and arbuscular mycorrhiza-reinforced defense against herbivorous insects. Annals of Botany, Volume 119, Issue 5, March 2017, Pages 791–801, https://doi.org/10.1093/aob/mcw263

Southwood, T. R. E., and M. J. Way. 1970. Ecological background to pest management. Pages 6–28in R. L. Rabb and F. E. Guthrie, eds. Concepts of pest management. North Carolina State University, Raleigh, NC.

Therond, O., Duru, M., Roger-Estrade, J. et al. A new analytical framework of farming system and agriculture model diversities. A review. Agron. Sustain. Dev. 37, 21 (2017). https://doi.org/10.1007/s13593-017-0429-7

Van Lenteren, J., Sharad C. Phatak, James Tumlinson. “A Total System Approach to Sustainable Pest Management,” National Academy of Science – Proceedings paper,1997. 

Warnert J. 2009. The 50th anniversary of a great idea: Landmark article on “integrated control” considered “most important” pest control paper of 20th century. Calif Agr 63(4):160-161.

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