by Ron Whitehurst, PCA, and co-owner Rincon-Vitova Insectaries, Inc.
DEFINITIONS ARE CRITICALLY IMPORTANT
We sometimes hear people talk about “biologicals” as if the word is interchangeable with biological control. It is an example of lack of understanding about the full meaning of biological control in the transition away from conventional chemical control. Agreement on the vocabulary for agroecology, insect ecology and biological control is essential for productive conversations and successful pest management.
We like to use definitions from Biological Control by Natural Enemies (1974) by Paul DeBach modified by Huffacker and Dahlston to include antagonists of plant pathogens. These align with those used by David Headrick, Professor of Agricultural Entomology, Biological Control of Agricultural Pests, Vertebrate and Insect Pest Management in the Plant Protection Science Program at Cal Poly San Luis Obispo.
In a recent personal communication, Dr. Headrick wrote:
“Definitions are critically important, and I am particularly frustrated by the blurring of the lines on what is and isn’t biological control throughout the industry. I agree with the definitions of biological control that you have provided below. It is important to consider the difference between natural control and human-aided biological control, with biological control being the use of populations of natural enemies (imported or naturally occurring) to control or reduce populations of pests with various methods.”
Our mentor Everett J. “Deke” Dietrick favored Paul DeBach’s terms and ideas. Deke, Paul, Blair Bartlett and a few other eminent biocontrol entomologists shared a love of not just biological control, but also enjoyed a long friendship and lively discussions while searching for the perfect skin diving cove between Laguna and Cabo Pulmo. Such conversations animated their lunch hour handball games at the Riverside Citrus Experiment Station (now UCR) as well as field trips including with Evert Schlinger, Robert van den Bosch, Fred Legner, Dan Gonzales, and others. This cadre of biocontrol entomologists helped Deke develop the clarity and confidence to leave the University of California and become the first consultant in California relying solely on biological control by natural enemies to manage pests. This was before the invention of the term “IPM or Integrated Pest Management”. He called what he and enthusiastic consultant associates did for farmers “Supervised Control”.
The birth of IPM and EBPM (Ecological-Based Pest Management) and the ‘Path of a Paradigm’ will be a later deep dive in this series for those interested in a sufficiently broad conceptual framework for talking about transition. But first, let’s agree on the terminology.
RECOMMENDATIONS FOR DEFINITIONS:
Biological control, when considered from the ecological viewpoint as a phase of natural control, can be defined as the action of parasites, predators, and pathogens and antagonists in maintaining another organism’s population density at a lower average than would occur in their absence. [DeBach, 1974]
- Note: It can be measured, human manipulation is not implicit and it does not include plant selection for resistance to pests. Biological control by natural enemies is central to transition from chemical input-dependent systems. When monitoring shows that there are enough natural enemies so that biological control is working, the complexity of phenomena may be too costly to measure and assess what actions are critical. The greater the biodiversity, the greater the complexity of interactions, the greater likelihood of a good ratio of natural enemy populations over pest populations. (See monitoring)
Applied biological control is the study, importation, conservation, and augmentation of natural enemies for the regulation of population densities of other organism’s abundance below the level of economic injury. Applied biological control can be achieved in differing degrees of economic importance which have been distinguished as partial, substantial or complete.
Natural control (sometimes called naturally occurring biological control) may be defined as the regulation of populations within certain more or less regular upper and lower limits over a period of time by any one or any combination of natural factors. [DeBach, 1974]
Augmentative biological control is the mass collecting or rearing and release of natural enemies (predators, parasites and pathogens) to control pests in a timely seasonal or inundative manner to prevent population increases, or to suppress a pest population, sometimes called inundative releases to differentiate from colonizations.
Classical or importation biological control is the foreign exploration, importation and colonization of natural enemies of a pest of exotic origin that lacks natural enemies to suppress their populations.
Conservation biological control is about conserving natural enemies either by reduction/elimination of toxic pesticides or enhancing/modifying the environment to invoke/enhance/supplement natural control.
- Note: This is a useful definition that covers all of the newer terms like ecological pest management in regenerative organic agriculture, farmscaping, biodiversity-based agriculture, and so on, that work by conserving biological control.
Biological control monitoring consists of skills and tools to assess the ratio of the pest and natural enemy populations to indicate whether biological control is increasing or decreasing. Each farming and cropping system has relevant observable phenomena that can be identified, counted, recorded, and compared with samples from other sites or time scales. Sometimes visual inspection, sticky or pheromone traps are sufficient. Sometimes a sweep net is essential and sometimes a vacuum insect net is the only way to observe the presence of important natural enemies. Identification of organisms follows monitoring of the insect ecology. The required accuracy in counting sample contents and the precision in identification depends on the level of consequence for cost-effective decision-making.
Biological action level is the density of key pests relative to the biological control at a particular stage in the crop cycle and the pest cycle that suggests that the application of one or more natural enemies will help ensure that the pest population stays below economic injury levels.
- Note: David Headrick explains that the timing of applications of natural enemies, i.e. the biological control action levels, has to be carefully thought through and monitoring has to be more intensive than for chemical control action levels.
Economic injury level is the number of insects (amount of injury) that will cause yield losses equal to the cost of insect management – generally used for pesticide application decisions.
Chemical action level or threshold is the pest density at which the pesticide application should be done to prevent an increasing pest population from reaching the economic injury level.
Beneficial organisms in the context of SPM are predators, parasites, and pathogens and their antagonists contributing to biological control. The term does not typically include fish, amphibians, birds, reptiles, and mammals, but it can.
Natural enemies in the context of SPM refers collectively to all of the predators, parasites, and pathogens and their antagonists that reduce numbers of pest insects and mites, and may include fish, amphibians, birds, reptiles, and mammals, e.g. bats and other rodents. Organisms can have key roles as predators and may also transport beneficial parasites and pathogens in biodiversity-based farming systems. [UC-IPM]
Biologicals are products derived from naturally occurring microorganisms, plant extracts, insects or other organic matter that may be categorized as 1) biostimulants to enhance plant growth and productivity, 2) biopesticides to protect plants from pests, or 3) biofertility or plant nutrition products.
Note: A “biological” is an input whereas “biological control” is its larger sense a characteristic of the ecosystem. Biologicals are often products viewed as alternatives to chemical pesticides. They may still disrupt biological control by negative impacts on natural enemies.
Biopesticides are certain types of pesticides, 1) biochemicals, 2) microbials, and 3) Plant-Incorporated-Protectants (PIPs) derived from such natural materials as animals, plants, bacteria, and certain minerals. [US-EPA]
Biological control entomology is the applied branch of zoological study dealing with insects and loosely including other arthropods (e.g. spiders and mites) for the purpose of controlling pests through conservation, importation, colonization and augmentation of beneficial organisms. Biological control deals principally with insects because most pest species are insects and most insect pests have natural enemies.
Biological control phytopathology and entomo-pathology are branches of study dealing respectively with the interaction between pathogens and plants and between pathogens and insects.
Biodiversity-based farming systems rely on re-designing the site-, space-, and time-specific practices and production approaches to create a high biological diversification and intensification. It is knowledge-intensive with outcomes of greater productivity and fertility from less exogenous inputs, and greater resilience to external impacts. This approach introduces a paradigm shift in expectations. It requires integration of interconnected processes, including influences of chemicals and/or low and very low short low-frequency waves, as well as integration of organization levels in ecological systems, such as landscape level populations and communities. [Duru, et. al. 2015]
Biological input-based farming systems rely on external biological more than chemical inputs to increase efficiency in combination with incremental substitution changes or system adaptations, such as organic fertilizers, and low-risk biological and botanical pesticides that mimic natural phenomena in biodiverse agroecosystems. This approach may integrate conservation, colonization and/or augmentation biological control [Duru, et. al. 2015]
Chemical input-based farming systems rely on external chemical inputs and technologies for improved efficiency and yield, that often include the use of Haber-Bosch-based nitrogen, potassium, and phosphorus fertilizers and chemical pesticides that optimize yield while limiting pollution. This approach may integrate conservation, colonization and/or augmentation biological control. Prohibition of nitrogen run-off may lead to use of cover crops in sensitive areas or in landscape features to prevent water pollution. Larger farm sizes and economies of scale may be required to afford the cost of technologies, such as sensors, spray equipment with targeting ability, drones, robots, satellites, cultivars and animal breeds. [Duru, et. al. 2015]
Efficiency/substitution approaches are economically driven practices within a chemical or biological input-based farming system. They are often top-down, developed by companies selling products or advisors that have evaluated products to meet expectations of greater profits by greater efficiency and use of technologies and innovations that reduce costs. [Duru, et. al. 2015]
Integrated Pest Management (IPM) IPM is an ecosystem-based strategy that focuses on long-term prevention of pests or their damage through a combination of techniques such as biological control, habitat manipulation, modification of cultural practices, and use of resistant varieties. Pesticides are used only after monitoring indicates they are needed according to established guidelines, and treatments are made with the goal of removing only the target organism. Pest control materials are selected and applied in a manner that minimizes risks to human health, beneficial and nontarget organisms, and the environment. [UC-IPM]
Sustainable Pest Management (SPM) is an agroecological approach within a spectrum of continual improvement to prevent, minimize, and manage pests in ways that protect human health and are environmentally sound, socially equitable and just, and economically viable. Pests are managed by combining biological, cultural, physical (including the use of new technologies that can improve detection, precise interventions, and plant resistance to pests), and, only when absolutely necessary, chemical tools, in a way that minimizes economic, health, and environmental risks.
Organic as a labeling term indicates that the food or other agricultural product has been produced by approved methods. USDA organic regulations require the application of a set of cultural, biological, and mechanical practices that foster cycling of on-farm resources, promote ecological balance, and conserve biodiversity. These include maintaining or enhancing soil and water quality; conserving wetlands, woodlands, and wildlife; and avoiding use of synthetic fertilizers or pesticides, sewage sludge, irradiation, and genetic engineering.
Regenerative agriculture has been called a land management philosophy. It involves the development of biodiversity-based farming systems focused on agroecological principles and practices that
- minimize soil disturbance;
- cover soil by mulching and multi-species cover crops or pasturage to prevent erosion and minimize weed growth;
- rotate crops to increase nutrient cycling, soil fertility, and water retention;
- increase plant diversity to conserve wildlife, pollinators and biological control and increase soil microbial abundance;
- keep living roots in the soil as much as possible to protect soil microbes and retain water and nutrients; and,
- integrate animals into the farm as much as possible that adds nutrients and builds soil organic matter.
It draws on knowledge from agroecology, agroforestry, organic practices, and holistic and rotational grazing. It offers increased yields and profit, improved watersheds, and enhanced ecosystem services, such as restoration of small water cycles, carbon drawdown and potential for accreditation for carbon and “eco” credits, resilience to climate instability, and better health and vitality for farming communities.
Regenerative organic encompasses organic farming and then raises the bar, prioritizing building soil health as a way to fight climate change. A holistic system, regenerative organic sees the well-being of earth, humans and animals as interconnected. High standards for animal and worker welfare are critical. It does not mean that the farm has Regenerative Organic Certification; it means that the farm is striving to apply these principles. [Patagonia Provisions]
Regenerative Organic Certification (ROC) is a label that can be added to organic certification for farms that meet higher standards in three areas: Soil Health & Land Management, Animal Welfare, and Social Fairness. Producers can choose to meet a beginning set of criteria (Bronze), an intermediate (Silver) or the highest achievable level of regenerative organic production (Gold). There are additional fees for ROC certification.
Real Organic Project (ROP) is a label that can be added to organic certification for farms that grow their plants in healthy, living soil and raise their animals humanely and on pasture to help consumers differentiate farms that are growing their animals and crops to both the letter and spirit of the certified organic standards. There is no fee for ROP certification.
Demeter Biodynamic Certification is a label that indicates that a comprehensive organic method has been used that requires the creation and management of a closed system minimally dependent on imported materials, and instead meets its needs from the living dynamics of the farm itself. The standard reflects the characteristics of biodiversity-based farming systems. There are fees to become certified.
REFERENCES
DeBach, P., Biological Control by Natural Enemies, Cambridge University Press, 1974.
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
Huffaker, C.B. and D. L. Dahlsten, “Scope and Significance of Biological Control”, in Bellows, T. S. and T. W. Fisher, Ed: Handbook of Biological Control, Academic Press, 1999.
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