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Our Vision for Sustainable Pest Management – Part 4: Biological control action levels–examples from the field

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

Pest Control Advisors (PCAs) make their decisions based on monitoring to determine an “action level” or “action threshold”. In other words, they look for signs that it is time to do something to prevent a serious pest problem. To align PCAs with the SPM goals, it is important that they understand the big difference between action levels for the conventional chemical input-based farms most of them are familiar with compared to farm systems that are either biological input-based, such as most organic acreage, or biodiversity-based. 

Treatment action levels on chemical input-based farms, of course, do not apply when chemicals are not an option. A new framework is needed for such farms. PCAs need training in determining “biological action levels”.  Entomology professor David Headrick asks his students at Cal Poly San Luis Obispo to think about two separate thresholds, one for chemicals and a different one for biological inputs. The following slide from his Biological Control class helps illustrate the need for early regular monitoring at low pest densities in order to time a natural enemy release to maintain the pest population at a low density. The timing of applications has to be carefully thought through. It is clear that the Economic Injury Level and the Chemical Control Action Threshold happen at a significantly higher pest density. 

Biological action threshold graph, Professor David Headrick, Cal Poly SLO Biological Control Course Lecture

As Dr. Headrick further explains, “Maintaining pest densities at low levels is most easily and effectively done with biological control agents. That is what they evolved to do – find prey when they’re scarce. It is also the most economically sustainable approach.”

Readers of “ACRES USA – A Voice for Ecological Agriculture” have been informed for decades about the potential for insects to find food and mates through subtle phenomena happening at low population densities. Dr. Philip S. Callahan, a regular contributor to ACRES USA, published Tuning In To Nature in 1975 describing experiments demonstrating insect behavior in response to low electromagnetic energies. He wrote, 

“A sick plant actually sends forth a beacon, carried in the infrared, attracting insects. It is then the insect’s role to dispose of this plant deemed unfit for life by nature…. Early in my career, I studied pesticides, as did all entomologists. But the findings I released…taught me that attempting to poison insects was at cross purposes to nature and would, in the end, prove futile.”

Biological control practitioners would never consider a biological action, such as releasing a few green lacewing larvae, when pest densities are high. Biological action levels must be earlier, at the first sign of a key pest in the season, when successful biological control is achievable. Consideration is also given to various cultural practices that minimize disruption of biological control. Long-range planning for habitat enhancement is another consideration.  Enhancing habitat in the long term can maintain pest levels at such low densities that monitoring does not need to be as in-depth or as frequent as field scouting shows no sign of reaching a biological action level. The focus of field scouting evolves to be more about continuing to enhance and monitor natural biological control.

Biological control entomology intersects not only with agroecology, including soil ecology, conservation biology and population dynamics, but also increasingly with molecular biology and insect-insect and plant-insect communication. Farmers and their Pest Control Advisors will need to be observant of population dynamics at the landscape scale and how insect and plant volatiles affect plant defenses and insect behavior. 

Dr. Joseph Patt with the USDA-ARS received doctorate degrees in both entomology and botany. His research on releasing parasitoid wasps for control Colorado potato beetle in eggplant led him to measure the accessibility of nectar in different potential habitat plants to make sure there was enough space in the floral architecture for the large heads of the wasps that the New Jersey State Insectary produced. Without nectar, the number of required wasps was unaffordable. By comparing 15 different plants and choosing to plant seed dill and coriander that have many flowers with open nectaries, he ensured adequate nutrition for wasp searchability and reproduction. This minimized the number of wasps that had to be mass-produced for a cost-effective program of one row of floral habitat every tenth row. Unfortunately farmers dropped the biological program when the EPA registered a new chemistry with Colorado potato beetle in eggplant on the label. Research funding in this area also disappeared. 

Diagrammatic representation in lateral view of the floral architectures on which E. puttleri and P. foveolatus were evaluated showing position of the nectar glands (in black) in relation to the other floral parts: (1) Umbels with exposed nectaries; (2) Cyanthia with exposed nectaries; (3) Umbels with partially hidden nectaries; (4) Cup- shaped flowers with partially hidden nectaries; (5) Capitula with hidden nectaries. Wasps are drawn to scale and are 3 mm long. Patt, et. al. 1997.

Many observations go into determining the presence of effective natural biological control. However, Pest Control Advisor training has been nested within a Production Agriculture curriculum, isolated from the sciences that explain population dynamics, and insect and plant physiology, biochemistry and electromagnetic communication to enhance biological control. To be aligned with SPM, the curriculum for PCAs must be equally nested within agroecology and the sciences that explain plant defenses and insect and mite behavior.

Dr. Headrick motivates his students to learn how to manage pests on regenerative organic farms by reminding them of the unsustainability of conventional chemical control. He tells them, “Chemicals are great for instant gratification, but not for long-term success in pest management.” This fact leads his students into the whole subject of pesticide resistance.

To be able to forecast whether population densities are approaching action levels, there is much to learn. Then, they have to be able to help farmers understand these concepts. Much research is needed for both areas of pedagogy. Scientists in France are developing learning models and games that teach decision-making about biological action levels. With such limited current training for PCAs, an entry level field scout requires at least two years of mentored field experience to learn basic skills to recognize action levels. Scouting in a variety of crops and farming systems is more challenging. It takes more years to be able to perceive the population dynamics and consider alternative cultural practices and cost-effective, manageable habitat enhancements and communicate with farmers to understand the options.

I enjoy those experiences when someone buys a rundown chemical farm and contacts me wanting to be organic. We start early in the fall to plan. I now know that measuring the upper and lower levels of compaction levels in the soil is critical to deciding on tillage. What characteristics are needed in a ground cover? Is good quality compost available?  Are ants likely to interfere with biological control? Where should this farm start with permanent habitat installations?

Early in the growing season there might be indications that one or more colonizations in perennial crops might help. Pest populations often stay so low that a biological action threshold is never reached and there is no need for augmentative releases or “treatments” with natural enemies. 

Here are a few examples to illustrate how biological control scouts determine a biological action level. 

Farm & location: Sanford, Santa Rosa Rd, Buellton

Size & farmscape: 12 acres between road and steep hillside, across the road from organic farm and Santa Ynez River, east-west river valley 16 miles from coast, diurnal breeze

Farming system, prior crop(s) & years in transition: at least a decade of chemical input-based lima beans, year 1 transition to organic

Crop(s) and key pest(s) & economic threshold: lima beans, two-spotted spider mite, in past would defoliate if not sprayed at least once, usually 3-4 times with conventional miticides

Cultural adjustments: none

Habitat enhancements: two interplantings ‘Beneficial Blend” with 20+ species plus weedy alfalfa, successional sweet corn, sorghum and sunflowers, perpendicular to prevailing westerly wind, 1) 30 ft from west end, 10 ft wide X 40’ long, 2) middle of 12 ac block, 10’ wide X 80’ long, 

Natural enemy colonizations: none

Monitoring method(s) and frequency: visual appearance of necrosis from spider mite damage, live mites and eggs, weekly across in 3-4 places and along perimeter 

Biological action level: monitoring showed the biological control from the interplantings protected most of the block except the south border on the east end  edges along the hill and drive road becoming infested; without natural enemy release, if there were hot, dry weather the mites could spread into the middle of the field protected by the biological control from the interplantings; mites could blow up requiring a spray to protect the whole block 

Action & result: two weekly releases of Galandromus occidentalis and green lacewing along the south border of the eastern half of the block brought the pest mites under control 

Farm & location: Dairy barn outside of Gunnison, Colorado

Size & farmscape: 10 cows, 1,000 sf open front, 3-sided, free-stall barn; manure moved daily to compost yard

Farming system, prior crop(s) & years of transition: organic cows over ten years

Crop(s), key pest(s) & economic threshold: houseflies annoy cows, reduce milk output

Cultural adjustments: more frequent clean-out, bucket trap near compost

Habitat enhancements: n/a

Natural enemy colonizations: monthly releases 10,000 fly parasites beginning at first sign of flies

Monitoring method(s) and frequency: 3X5 index “spot cards” counted weekly. Start with 4 cards and reduce to as low as 2 cards if counts are within 10%. Place one on the warm side and one on the cool side, one upwind and one downwind if there are differences.

Biological action level: average 100 spots/card, over 65’F so flies are active

Action & result: balEnce Fly Spray (beneficial fungus Beauveria bassiana) on surfaces; average spots/wk below 20.

Farm & location: Anonymous, Edna Valley, San Luis Obispo County

Size & farmscape:  Two fields separated by a seasonal creek: 40 acres and 35 acres, sandy loam soil.

Farming system, prior crop(s) & years of transition:  Standard, previously farmed as vegetables, conventional production, but no synthetic pesticides used.  I was hired to manage the crop start to finish using only biological control.  

Crop(s), key pest(s) & economic threshold:  Hemp for CBD, key pests:  western flower thrips, spidermites, noctuid caterpillars, botrytis.  CBD products are supposed to be made from plants without any pesticide residues and with as few contaminants as possible.  In this case having biological control agents on the plant surfaces at the time of harvest was deemed acceptable for the CBD extraction process.

Cultural adjustments:  Typical row crop approach, plastic mulch on beds, 40 inches on center, transplants at 2 foot spacing.  Transplants grown in a greenhouse from certified seeds.

Habitat enhancements: None.

Natural enemy colonizations:  In the greenhouse setting, the following natural enemies were released at standard rates so that they were actively foraging and reproducing on plants before they were placed in the field – a “pre-transplant inoculum”: Orius releases were made for thrips, Stratiolaelaps scimitus (Hypoaspis miles) was inoculated onto the transplant container soil surface for fungus gnats, lacewing eggs for whiteflies and small lepidoptera and Aphidoletes aphidimyza for aphids.  

In the field, subsequent releases were made based on monitoring.  Spot treatments of Neoseiulus californicus was made for spidermite control.  Bacillus thuringiensis was applied as a spray for caterpillar control.

Monitoring method(s) and frequency: Greenhouses were monitored with visual inspections, tap method and yellow sticky cards.  Monitoring was done once a week until plants reached about 8 inches tall, then twice a week until transplanted.  

Fields were monitored with visual inspection and beat sheet.  

Field monitoring was conducted once a week along rows, every 6th row but different rows each time, and always checking the first three upwind rows and two downwind rows each time.  

Biological action level:  All biological control agent releases (greenhouse and field) were made only if the target pest was present.  Thresholds were set “at first sight of pest”, with the idea that pests at low population densities are more easily controlled.  Most mite issues started on the upwind rows, predatory mites were applied as spot treatments.  N. californicus was chosen due to the hot, dry conditions and its ability to feed on prey other than T. urticae.  Bt sprays were applied to the entire field as soon as adult moths were observed being disturbed by the beat sheet monitoring methods.  Lepidopteran eggs were impossible to locate on the dense and trichome-laden foliage and flowers and waiting until feeding damage was readily observed was too late to gain control of the caterpillars.  The concern with caterpillar feeding was not so much the foliage, but the flowers.  When caterpillars fed in the dense flower clusters, they were virtually impossible to see and the feeding damage resulted in Botrytis infections.  Botrytis is a devastating fungal pest and will ruin a crop because it negatively affects the terpenoid extractions.  Closer to harvest, Bt sprays were conducted once a week as per the growers request.  

Action & result: I achieved excellent results with a 100% harvestable crop.  The greenhouse inoculation program was an effective and cost-efficient approach to having natural enemies evenly spread throughout the field and working on pest populations before full exposure to field conditions and new pest populations.  The approach of applying biological control agents on mature plants in the field can often lead to losing many of them during the process.  The Bt sprays were effective, but caterpillar control needs to be re-evaluated and diversified to avoid resistance.  Additionally, making spray applications on the dense flowers can itself lead to conditions that aid fungal growth.  Consistent, systematic, monitoring from crop onset and application of appropriate biological control agents when pest populations were extremely low was the recipe for success.  

Farm & location: Millennium Grove, Santa Paula, CA

Size & farmscape: 5 acres, landfill on long side

Farming system, prior crop(s) & years of transition: biological input-based;  sandy rocky, not organic

Crop(s), key pest(s) & economic threshold: Haas avocado (flowers Feb-May), persea mite; 8% leaf damage can cause defoliation

Cultural adjustments: 3-6 inches mulch, seaweed+high quality compost extract foliar 5X between Feb & June (flowering period), no artificial nitrogen or mineral fertigation 

Habitat enhancements: one “predator food station” every 8-12 trees, 1-2 stations/acre (with 12-20 plants of corn/acre (early, middle, late varieties planted monthly in April, May & June with Johnson grass and/or native creeping ryegrass or other grass with summer through fall flowering); maintain by watering each monitoring visit, cutting some bloom from grass patches when flowers are done to stimulate new flowering for continuous production of pollen blowing onto surrounding trees to maximize reproduction of predator mites

Natural enemy colonizations: none

Monitoring method(s) and frequency: spring & summer every other week, fall & winter monthly. Machlitt method: number of random leaves with one or more persea mite.  Number of Euseius hibisci  mites feeding on Persea mites on 50 random leaves 

Biological action level: Release N. californicus (Nc) predator mites by blower. Number depends on month, heat, humidity: 

  • April-June below 85’F, 25 leaves out of 50 w 1+ Persea, <10 Euseius: 100 Nc/tree first release
  • July-Sept below 85’F,  same levels as above: 150 Nc/tree first release
  • Forecast of Santa Ana winds (<10% humidity):same levels as above:  200-250  Nc/tree if first release
  • Forecast of heat wave over 100’F for 3+ days: no release since Persea die

Action & result: One June release of 100 Nc/tree resulted in <2% leaf damage; monitoring in August showed 15 Euseius/50 leaves; some corn and grass still producing pollen; Persea stayed below action level 

Millennium Grove. Trials of cover crops, grasses, weeds, and occasional corn hills to supply pollen to increase reproduction of predatory mites.

Farm & location: Christmas tree farm, Decatur, Illinois

Size & farmscape: 50 acres edge suburb, riparian native woodland east side, monocropped farm blocks three sides 

Farming system, prior crop(s) & years of transition: biological input-based Christmas trees for 20+ years

Crop(s), key pest(s) & economic threshold: 30 acres in Mugu and Scotch pine trees, pine needle scale, average 5 covered scales per needle on 10% of needles after pruning out the current year’s infested needles 

Cultural adjustments: Pruning infested branches

Habitat enhancements: permanent border of pine trees, mowed grass cover crop, one strip native flowering annuals per ten acres east-west

Natural enemy colonizations: none; Chilocorus lady beetles well established

Monitoring method(s) and frequency: double-sided tape around branch on warmest (south) side of tree, red nymph crawlers stuck on tape or on white paper on a clipboard when branch is hit over the paper once

Biological action level: average more than 1 nymph per tape or on white paper, release Lindorus lopanthae predatory beetles with 40/ac 1st release, 30/ac 2nd release two weeks later, and 1 or 2 more releases if crawlers continue to appear

Action & result: 2022 released total of 100 Lindorus per acre in four releases over 5 weeks during crawler emergence prevented development of noticeable armored scale


Patt, Joseph, George Hamilton, James Lashomb, 1997. Foraging success of parasitoid wasps on flowers: Interplay of insect morphology, floral architecture and searching behavior  Entomologia Experimentalis et Applicata, vol 83


Our Vision for Sustainable Pest Management – Part 3: Incentivize regenerative organic and ban disruptive chemical pesticides

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

“Organic” has different meanings, but the particular meaning that is quite valuable for making state policies is its meaning as “the USDA Organic Label” because it is working to help consumers support the farmers who have moved away from chemical input-based farming. From a farmer’s perspective organic 

The term “regenerative agriculture” also has varied meanings. “Regenerative” is an important term, because it is becoming increasingly recognized to have greater potential for carbon farming and carbon credits that are not as strong a focus in practices required for organic certification. The U. S. House Agriculture Committee recently held a hearing on “Soil Health Practices and Programs that Support Regenerative Agriculture”. “Regenerative organic” was the term they used to describe farming systems that sequester more carbon. There was agreement during the hearing that ‘standards’ for regenerative beyond those developed for the Regenerative Organic Certification label are not necessary. There are many ways to achieve the performance and economic outcomes beyond being organic that are recognizable and highly meaningful for farmers. The consensus advice among those farmers and their consultants walking this road is to just get started and to keep the metrics focused on what soil, leaf and sap analysis shows the crop needs to build soil microbiology and optimum plant health. The baseline is little or no toxic chemical or artificial nitrogen inputs.

“Biodiversity-based” is another useful term to describe a farming system that is getting off of disruptive pesticides. It is used by the preeminent French agricultural research team at INRA, because it is a descriptive rounding out of the concept of a continuum framework for change. The INRA framework and terms are descriptive without making value judgments, with chemical input-based farming systems at one end of the continuum and biodiversity-based at the other end. Biological input-based systems are the ones in-between.

The INRA farming system framework is useful for those reasons, but we also still need to refer to organic and regenerative agriculture if we are serious about getting off of chemical pesticides because organic is how the market supports farmers, and it is measurable and growing, despite red tape, costs, and sometimes frustrating arbitrary standards in the National Organic Program. Regenerative is the term farmers are using to describe the systems changes that are working well for them to transition away from chemical inputs. Finally, a movement is emerging that is being called “regenerative organic” where the economics are favorable and the resilience value is vital. 

Camarillo organic farmer Phil McGrath of McGrath Family of Farmers and his biodiverse habitat border planting.

Transition to organic must be incentivized to scale pesticide use reduction. Public kitchens should be required to spend a gradually increasing part of their budgets on products labeled organic that are grown locally. It is smart to make the most of the developed infrastructure for certifying and inspecting and continuous review of the standards for eliminating use of synthetic pesticides. California’s newly enacted goal of net carbon neutrality by 2045 is going to prioritize investment in organic farms to make more farms sequester more carbon faster. Such farms experience fewer pest problems. The future is bright for achieving ambitious goals, because it is more profitable when farmers learn to grow healthy soils that grow healthy plants that minimize pests.  In a future article we will share more of the science behind that.

The state should incentivize farmers to transition including paying organic fees. Subsidizing the costs to be certified organic is a no-brainer. County jurisdictions can also support local organic farmers. A 2016 survey showed that in counties characterized as an “organic hotspot” the median household income was $2,000 higher and the poverty rate was 1.35% lower (Jaenicke, 2016). Counties may offer favored tax treatment, help with Land Conservation Act contracts, and earn income from carbon farming accreditation. 

Some organic farmers can meet the minimum standards, but are not building the healthiest soil or producing the healthiest plants that resist pests. The standards and inspections do not go deep enough to ensure systemic changes that are considered regenerative or biodiversity-based. The biological inputs allowed in organic can be costly and disruptive to biodiversity and biological control. Yet, organic certification of acreage is a ready benchmark, because it says that the farmer is moving toward a farming system that serves the state’s goals.  Not only should we use the metric of “percent of farm acreage in organic” to measure progress, we should also incentivize farmers to become certified in ANY comparable label, e.g.  Real Organic Project, Regenerative Organic Certification, and the Demeter Biodynamic Certification. Consumers keep learning how and why to support the more resilient biodiversity-based farms that protect people and biodiversity. 

Our goal can be that organic acreage reaches 30% of all California farmland by 2030 from 4% last year, and to 80% by 2040. 

Meanwhile, what do we do with all these toxic pesticides? First, we should develop and promulgate real SPM alternatives and enforce laws that require the consideration of alternatives. Agriculture Commissions provide limited transparency and consistency about compliance with state law to consider alternatives before permitting use of Danger and Warning signal word registered materials. 

Create a Community Support Fund to provide direct protections from Danger and Warning signal word registered pesticides. This includes buffer zones, indoor home air purifiers/filters, tarping of all fumigations, personal protective equipment and other actions that minimize synthetic pesticide exposure for people nearby. There is additionally an urgent need for cancer cluster studies and other exposure programs to identify and help communities burdened with chronic health impacts. Decisions on how the fund is spent are the prerogative of those most impacted by pesticide use. 

Notify interested people of intent to use pesticides via texts or emails at least 72 hours before site-specific intent to use all Danger and Warning signal word pesticides (not just Restricted Materials). A notification program should be done for all products with potential acute or chronic risk to people on and near the site. Access must be available to those not living nearby, e.g. consultants and migrant laborers who need to know when toxic chemicals are planned before traveling to a farm.

Ban neonics. They were supposedly proven to have very low mammalian toxicity, but with time we’ve found that neonics are associated with damage to nerve cells and developmental and reproductive problems, including congenital heart and brain defects in which a large part of the skull is absent along with the cerebral hemispheres of the brain. There are also associations with autism and a disorder involving both memory loss and finger tremor. It is ironic that the macho act of spraying pesticides to kill and dominate pests results in effeminized male offspring. Touted as low-risk because users didn’t die immediately and the disastrous effects on pollinators were buried and suppressed through the influence of manufacturers. The EPA has been captured. Harm to reproductive organs was not studied and the other findings have not been taken seriously. [Omidashk 2022]

Ban glyphosate. FDA scientists determined in 1984 that this active ingredient in herbicides like Roundup is a human carcinogen, but there were internal EPA disagreements about the significance of the finding.  A 2001 study again showed malignant lymphoma in mice exposed to glyphosate. A follow-up study concluded glyphosate exposure can result in liver and kidney damage. A literature review in 2015 showed birth defects, tumors and liver damage at doses below the dose that industry tests deemed safe.  Other animal studies show endocrine disruption, reproductive and developmental damage, including damage to sperm, damage to DNA, and neurotoxicity. [Robinson, 2018] 

Diagram of different negative effects of glyphosate, the active ingredient in Roundup herbicide. Formulated herbicides with glyphosate are 10 to 100 times more toxic than glyphosate,
depending on target species.

Ban pesticides whose toxicity tests have been determined to have been falsified. The toxicity studies on glyphosate and Roundup have been shown in public records requests from EPA to have been falsified, likewise the studies of Chlorpyrifos effects on pollinators that finally led to California banning it. What other tests were manipulated to pass safety tests? The harmful physiological effects of paraquat and rotenone are undisputed, but the epidemiological studies for relationship to Parkinson’s Disease and cardiac disease are mixed. Is the data from necessary two-year animal studies trustworthy? At least 85 pesticides have been banned in China, Brazil, or the European Union that were still used in the U.S. in 2016 and that number has almost certainly increased. 

Ban pesticide formulations that have not been the subject of long-term safety studies. There is strong evidence that adjuvants contained in pesticide formulations can be highly toxic compared to the active ingredient alone. The formulation of  herbicides containing glyphosate have never been the subject of long-term safety studies.The actual product that we are exposed to must be tested, otherwise all safety claims are bogus. [Cox and Zeiss 2022]

Ban all pesticides that make people sick. Consider people who don’t have significant input into the decision about whether to register the pesticide. Farmers put toxins into the environment, the commons, that cause their neighbors harm, using a license from the state.  Financial considerations have been more important to DPR than protecting public health. Or as Will Rogers, Cherokee and cowboy humorist, said, “we have the best government that money can buy.”

Decrease use of and phase out pesticides that may contribute to cumulative effects, gut microbiome disruption, and Toxicant Induced Loss of Tolerance (TILT) in which the nervous system reacts in a wide array of symptoms after low-level chemical exposures. Dr. Claudia Miller professor emerita at the University of Texas San Antonio raises connections to a wide range of public health diseases in numerous peer-reviewed publications, and the professionally acclaimed book, Chemical Exposures: Low Levels and High Stakes reporting on the failure of the regulatory system to fully evaluate and control for the range of adverse effects of pesticides and complexity of their interactions. 

Eliminate all toxic chemical pesticides by 2040 leaving only OMRI-approved products with no exceptions for emergency use for longer than three years. It took decades to finally get rid of methyl bromide after it was banned. 

In conclusion, banning toxic pesticides is easy when we are achieving the economic and resilience benefits of transition to regenerative organic agriculture and biodiversity-based farming systems.  Citizens of California are asking the state for relief from harm. Do not register toxic, hazardous, pesticides that make people sick and cause reproductive harm. Include actions to protect communities, particularly when we are just beginning to meet long-range reduction targets. Our system of evaluating toxicity and negative effects of pesticides is flawed. Particularly if we know these pesticides are causing harm, then the time to ban them is immediately. If the Roadmap aims for a 90% reduction in residues in soil, we need to start now, as the pesticide half-life must be taken into account, with some more persistent than others.  


Cox, Caroline and Michael Zeiss. “Health, Pesticide Adjuvants, and Inert Ingredients: California Case Study Illustrates Need for Data Access”. Environmental Health Perspectives, 130:8, Aug 2022.

Delta Institute and Earth Economics (2017). “Valuing the Ecosystem Service Benefits from Regenerative Agriculture Practices–Farmland LP 2017 Impact Report”.

Jaenicke, E. Penn State Ag Economist. (2016) U.S. Organic Hotspots and their Benefit to Local Economies prepared for Organic Trade Association

Omidakhsh, Negar, Julia E. Heck, Myles Cockburn, Chenxiao Ling, Jerome M. Hershman, and Avital Harari, “Thyroid Cancer and Pesticide Use in a Central California Agricultural Area: A Case Control Study”, The Journal of Clinical Endocrinology & Metabolism, 2022, XX, 1–9

Robinson, C., Antoniou, M., and Fagan, J. GMO Myths and Truths, 2018. Pp 149-162.

Our Vision for Sustainable Pest Management Part 2: Defining how SPM actions relate to each other- Rev 9/23/22 

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


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 Deke’s understanding about biological control drew on countless hours of discussions over many years including on skin-diving trips. Here are UC entomology researchers Everett “Deke” Dietrick (l) with Paul DeBach (center) and Blair Bartlett (r), Moro Beach ~1948.

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.   


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.


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).

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.

Our Vision for Successful Sustainable Pest Management – Part 1: The Centrality of Insect Biodiversity 

by Ron Whitehurst, PCA, with Jan Dietrick, MPH, Co-owners Rincon-Vitova Insectaries, Inc.

Everett J. “Deke” Dietrick
Robert van den Bosch

Appreciation to Deke & Van

We draw on what we learned from our mentor, Jan’s father, Everett J. “Deke” Dietrick, and Robert “Van” van den Bosch who dedicated their lives to biological control of pests, as we envision how SPM can work

In his memoirs Deke wrote: “There were such political challenges to carrying out the research I was doing to promote biological control by natural enemies that at this critical juncture in 1960 when modern organic chemistry was leading the “war on bugs”, I saw an opportunity to start a professional consulting service that sold pest management based on biological control. Having spent 15 years in classical biological control research, I was ready to try to reach growers with the news that biological methods are better than chemical methods.”  

Van summed it up: “The evolution of a rational pest-control strategy very much depends upon the outcome of this conflict…between those who are seeking change and those who want things to remain as they are.” From The Pesticide Conspiracy (1978) p. 91.

Part 1 – The Centrality of Insect Biodiversity

I am honored to have the opportunity to serve on the Sustainable Pest Management (SPM) Work Group advising the California Department of Pesticide Regulation on the development of a Roadmap to transition away from reliance on toxic pesticides. The group has 25 members. There are a few people like me who manage pests without chemical pesticides. There are also several experts in Integrated Pest Management, several who struggle with the idea of losing access to chemical pesticides, several representing farmworkers and a couple representatives of indigenous stakeholders, in this case Pomo Indians and another tribe, as well as toxicology exposure scientists, biodiversity and food protectors, and Houston Wilson, Director of the new University of California Organic Agriculture Institute. 

Good news! After well over a year of meetings, the consensus Roadmap is starting to come together. Meanwhile I have been collecting more ideas from friends about what it needs to be successful. Thanks to 22 friends who took time to give me some feedback, we have a great collection of important ideas that I’m forwarding to the SPM Work Group. Entomologists (professors and researchers) shared what I believe are the most important ideas. Four of them teach biological control to Pest Control Advisors (PCAs) and have a lot to say! Several PCAs and consulting agroecologists shared insights. The thoughts from organic farmer and field research friends Phil McGrath, Larry Jacobs, Steve Sprinkle, and Arianna Bozzolo of Rodale Institute confirm what we know to be true about the benefits and that farmers need help. I’m especially grateful to Annemiek Schilder at the Ventura County UC Cooperative Extension; Jo Ann Baumgartner, Director of Wild Farm Alliance; Daniel Gluesenkamp, Executive Director, California Institute for Biodiversity; and Nik Bertulis, Co-Founder California Center for Natural History, also a Permaculture Designer and Teacher, for their detailed suggestions. If you want to see the discussion draft or just have thoughts about what’s in this blog, let me know.

Out of the gate, my biological control friends agree that Sustainable Pest Management or SPM is a big step up from Integrated Pest management or IPM because it aims for long-term prevention of pests and their damage in a framework of increasing biodiversity. It is achieved by conservation biological control (including habitat enhancement and adjustments in cultural practices) as well as consideration of mechanical controls and use of resistant plant varieties. Chemical pesticides are used ONLY when other methods aren’t adequately managing pest populations. Definitions are critically important, which I’ll post about next. The Roadmap is easier to navigate when we understand what others are talking about! 

Our biological control sector lifts up the importance of increasing biodiversity–not just because it is the way to wean off of toxic pesticides–but also because we want the Roadmap to offer a positive vision of increasingly biodiverse farming systems that are more resilient with fewer problems and less costly inputs. This is what agroecology looks like. 

Experts in agroecology and biological control agree that the goal of the Roadmap is to move along a biodiversity continuum with metrics and targets for both below and above ground biodiversity. Jo Ann Baumgartner has already been traveling this road more on the above-ground level. Check out the publications by the Wild Farm Alliance that help organic farmers comply with the USDA National Organic Standards. The organic law requires that organic farms “foster cycling of resources, promote ecological balance, and conserve biodiversity.” Jo Ann published Positive Organic Indicators and Red Flags–Inspecting for Natural Resources and Biodiversity on Farms to standardize concepts for increasing compliance with the organic standard. Her work is expandable beyond organic to SPM. Another Wild Farm Alliance publication How to Conserve Biodiversity on the Farm: Actions to Take on a Continuum from Simple to Complex suggests what we know from science, that with complexity there is more biological control of pests. I plan on diving dive into this in my seventh post in this series. 

Organic farmers are leading the way to SPM. Every crop in California can be grown organically without artificial toxic inputs. Organic and especially regenerative organic farms have greater resilience to drought and floods and tend to reduce and sometimes nearly eliminate the need for costly fertilizer and pest control. Weeding, mulching, and the possible need for on-farm composting can require more labor. The farmer might need new types of equipment and inputs to build healthier soil and suppress pests, but before long the farm is more profitable and the benefits become evident. The first couple or three seasons building biological balance might keep the farmer awake at night, but, the way one of our customers put it, “Farming is fun again when I left the spray rig in the barn.”  For most organic farms, the focus is on increasing biodiversity within the root zone of the crop plants and then learning what kinds of above-ground biodiversity fit with the cropping system and meet the particular goals. 

The first idea from a few friends was about the necessity for regular landscape scale biodiversity monitoring as part of the principles and practice of agroecology. As Daniel Gluesenkamp, Director of California Institute for Biodiversity (CIB) explains, “We currently don’t even have a baseline inventory for insects. We don’t know how many insect species occur in California, maybe 50,000 to 200,000 with only 40,000 to 60,000 having been described by science.  We have no maps or good site-specific characterizations. We are blind. There are technical challenges in catching/viewing insects, especially the many tiny forms.”  We also need to know the negative impacts that affect non-target vertebrate species–insectivorous birds, birds of prey, amphibians, fish, and predatory mammals that is documented in this film: The great death of insects | DW Documentary. . We want a robust monitoring program rolling out in 2023. Numeric goals and target dates for establishing baselines and databases and monitoring infrastructure must be a top priority in the Roadmap.

CIB is doing DNA barcoding to establish baselines for insects and the Dietrick Institute for Applied Insect Ecology specializes in training women, farmworkers, and students in monitoring insect populations where farmers have installed habitat enhancements for natural enemies. The California Center for Natural History can pilot and train teachers and NGOs to organize citizen scientists to help count non-target animal species. Getting baselines is a costly initial undertaking, whereas the on-going monitoring will not be expensive. What areas need the most help? How well are we restoring biodiversity in priority regions? How does that correlate with pest pressures?

From United Nations Environment Programme, Foresight Brief No. 011, 2019, 
We are “Losing the Little Things that Run the World”

This important work to inventory California’s insects builds on my father-in-law, Everett (Deke) Dietrick’s work with Robert van den Bosch from 1953 to 1960 in the University of California Department of Biological Control cataloging all the insects in an alfalfa field using sweep nets, vacuum nets, and soil/duff samples. Dr. van den Bosch and Everett Dietrick observed that most of the insects in California agriculture could be found in untreated perennial alfalfa fields.

Working on the SPM Roadmap gives me hope. I’m excited to share in upcoming posts more about what I’ve learned with the Work Group. My partner Jan Dietrick is helping me organize our ideas with the input from our friends into a series of articles on the following topics.    

Part 2: Defining how SPM actions relate to each other 

Part 3: Incentivize regenerative organic and ban disruptive chemical pesticides

Part 4: Biological control action levels–examples from the field

Part 5: Regional SPM focus with RCDs, field scouts, food hubs and insectaries

Part 6: New knowledge for pest prevention

Part 7: What has to be different for SPM? [Hint: life]

Part 8: Myths and truths about pest control

Part 9: SPM for city people

Ron Speaks Truth about Pesticides

It started when we joined with Adam Vega for the founding of the Ventura County Coalition Advocating Pesticide Safety (VC-CAPS) in 2018. Adam introduced us to Californians for Pesticide Reform and we started sitting in on the “Alternatives Call”.  A big opportunity came up when Governor Newsom formed a new group under the Department of Pesticide Regulation called the Sustainable Pest Management Work Group with an assignment for a multi-stakeholder group to develop a framework for moving away from toxic pesticide use.  The group got more acquainted in July during its first field trip to farms in Watsonville.

CA Sustainable Pest Management Work Group visits the Driscoll's Research Farm in Watsonville on July 21, 2021.
SPM Work Group at Driscoll’s Research Farm July 21, 2021.

Ron is challenging the compromises society has made with polluting industries. He is calling for honest science to support rational pest management decisions. There is broad representation in the work group from commodity groups, pesticide manufacturers, and environmental justice leaders fighting to protect farm workers.  Ron is an ally of farm workers, a scientist and licensed professional Pest Control Adviser, whose outlook is that our life support system is failing and we have an existential imperative to change or write off our species.

While some around the table in such discussions believe it’s about ensuring that people follow the pesticide label to be safe, Ron cites the long-standing corruption at the US Environmental Protection Agency that registers products and decides how safe they are. They do that by simply asking pesticide manufacturers to supply the results of their trials to measure effectiveness and toxicity. The companies do the trials or they contract with specialized labs.

It’s becoming apparent that he who pays the piper calls the tune. A number of labs have been caught faking the data. The registration of Roundup (glyphosate) is a good example. Monsanto admitted that the toxicity study was flawed and agreed to repeat it, but never did. Monsanto made a science of how to do bad science. What is the extent of this misrepresentation? How many pesticides should have been put into higher toxicity classes—danger instead of warning or caution? Or should it have never been registered because it is just too toxic?  The evidence is mounting that no pesticide is safe when used according to label directions.  As Ron says, “The EPA needs a sticker or a rubber stamp that says ‘Incompatible with Life’ to stamp on applications based on questionable science.  Major industries that pollute and harm living things with impunity need to be shut down.”

The pesticide labels are one problem. The process of permitting at the field level is also in question. There is no way for farm workers and people on or near farms to know when there will be a spray and what the pesticide is. Farm workers have a right to know even if the label is based on fake safety studies.  VC-CAPS new leader Teresa Gomez organized a meeting with the Ventura County Agriculture Commissioner and deputies last week .  It was a positive discussion about how to protect farm workers and their families in the area around local farms. We were encouraged to propose a pilot project for text notification of sprays.

Source: Amadeo Sumano Sept 24 Oxnard 🌍🌍Essentials (🙌💯💯🍓🍓. Saludo de parte de nuestra comunidad campesinas locales 😊💯.
Source: Amadeo Sumano, Oxnard, CA Sept 24, 2021

We believe that if those who want to use chemicals that could poison people, wildlife, soil microbes, bees, beneficials, bats, butterflies–if they were required to notify workers and neighbors in advance, there would be a lot less unnecessary use of toxic pesticides.  The users of toxic pesticides would be motivated to learn agroecological systems that prevent pests and disease, i.e. cultural practices to grow healthy plants that resist pests, habitat enhancements for natural biological control and beneficial releases when nature is a little too little and a little too late.

All this talk may not get us too far, but it’s good to be at the table.


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