THE ECOSYSTEM MANAGER

A Project-Based Learning Module

Nuisance Biology · Integrated Pest Management · Wildlife Ecology · Historical Wisdom · Emerging Science

NBIO-110 / ECOL-110

Prepared by the Cade Moore Polytechnic Institute (CM-Tech)

Sponsored by the Cade Moore Foundation, 501(c)(3)

From Ancient Egypt to Gene Drives:

How Understanding Biology Can Replace Poison with Wisdom

IMPORTANT DISCLAIMERS AND LEGAL NOTICE

Please read the following disclaimers carefully before proceeding with this module.

This Module Is Educational and Philosophical in Nature

This project-based learning module is designed to introduce students to the broad concepts, history, biology, and emerging science related to nuisance species management. It is intended to develop critical thinking skills, encourage holistic problem-solving, and prepare students for further study in the field. This module does NOT constitute professional training, certification, or licensure in pest control, wildlife management, or any related field.

Not a Substitute for Professional Training or Licensure

The information presented here is based on publicly available research, case studies, and general educational principles. It should not be used as the sole basis for any pest management, wildlife control, or chemical application activities. Pest management is a regulated profession in all 50 states. Most states require specific licenses, certifications, and/or supervised apprenticeships before an individual may legally apply pesticides, handle wildlife, or offer pest control services to the public. Students should consult their state’s Department of Agriculture or equivalent regulatory body for specific licensure requirements.

Pesticides, Rodenticides, and Chemical Agents Are Dangerous

Many of the substances discussed in this module — including but not limited to anticoagulant rodenticides, sodium nitrite, diatomaceous earth, and various insecticides — are toxic, regulated, or both. Improper use of these substances can cause serious injury or death to humans, pets, livestock, and non-target wildlife. The discussion of these substances in this module is purely educational and does not constitute instruction on how to use them. Always follow EPA-registered product labels exactly as written. Always wear appropriate personal protective equipment (PPE). Never apply pesticides without proper training and certification.

Wildlife Handling Is Regulated

Federal, state, and local laws govern the handling, trapping, relocation, and management of wildlife species. Many species — including most migratory birds, raptors, bats, and certain mammals — are protected under laws such as the Migratory Bird Treaty Act, the Endangered Species Act, and various state wildlife codes. Unauthorized handling of protected species can result in significant fines and criminal penalties. This module discusses wildlife management concepts for educational purposes only.

Emerging Technologies Are Experimental

Several technologies discussed in this module — including gene drives, entomopathogenic fungi biopesticides, sodium nitrite toxicants for feral swine, and wildlife contraceptives — are in various stages of research, regulatory review, or limited deployment. Their inclusion in this module reflects their educational value as examples of innovative thinking, not an endorsement of their use. Some of these technologies have not received full regulatory approval. Others may have significant limitations or risks that are not yet fully understood. Students should rely on guidance from licensed professionals, regulatory agencies, and peer-reviewed research before drawing conclusions about any emerging technology.

Case Studies Are for Learning, Not Replication

The case studies and scenarios presented throughout this module describe real-world situations and research findings. They are included to develop analytical thinking and introduce students to the complexity of nuisance species management. They are not step-by-step instructions. The Cade Moore Foundation and CM-Tech assume no liability for actions taken based on the content of this module.

Diatomaceous Earth Safety Warning

Diatomaceous earth (DE) is referenced in this module as a naturally occurring pest control substance. While food-grade DE is generally recognized as safe for ingestion by humans and pets, it is dangerous if inhaled. DE particles can cause serious respiratory damage, including silicosis with prolonged exposure. Always use respiratory protection (at minimum, an N95 mask) when handling or applying diatomaceous earth. Never apply DE in enclosed, poorly ventilated spaces without proper PPE.

Consult Licensed Professionals

Before taking any action to manage pests, nuisance wildlife, or invasive species, consult with licensed pest management professionals, your state’s wildlife agency, and/or your local Cooperative Extension Service. The professionals in this field have years of training, hands-on experience, and legal authority that this module cannot replicate.

TABLE OF CONTENTS

Part 1: Meet Maya — A New Kind of Problem Solver

Part 2: The Oldest Profession You Never Heard Of — 5,000 Years of Pest Management

Part 3: Integrated Pest Management — The Philosophy That Changes Everything

Part 4: Know Your Enemy — Bed Bugs and the Biology of an Invisible Invader

Part 5: Heat, Cold, and Fungus — The New Arsenal Against Bed Bugs

Part 6: Rodents — Mammals with a Strategy

Part 7: The Poison Chain — How Rat Poison Killed a Mountain Lion

Part 8: Barn Cats, Bat Houses, and the Art of Biological Deterrence

Part 9: Feral Hogs — America’s Six-Million-Strong Invasive Army

Part 10: When Wolves Changed the Rivers — The Yellowstone Trophic Cascade

Part 11: Living in Harmony — Beavers, Geese, and the Case for Coexistence

Part 12: The Future — Gene Drives, Cryonite, and Fungal Biopesticides

Part 13: The Big Picture — You Are Not Just Removing Pests

Part 14: Resources for Further Learning and Professional Development

Part 15: Key Vocabulary

Sources and References

A Note to Our Students

PART 1: MEET MAYA — A NEW KIND OF PROBLEM SOLVER

Maya grew up in a household where her grandmother kept a garden that never seemed to have pest problems. While neighbors sprayed chemicals on their tomatoes, her grandmother planted marigolds around the border, scattered crushed eggshells near the lettuce, and hung old CDs from strings to flash in the sunlight and scare birds away from the berry bushes. When a family of mice moved into the garage, her grandmother did not put out poison. She sealed the gap under the door with steel wool, moved the dog food into a sealed container, and within two weeks, the mice left on their own. There was nothing to eat and nowhere to get in.

“If you understand why something is there,” her grandmother used to say, “you can figure out how to make it leave without having to kill it.”

Maya is now studying to become a professional in the field of nuisance species management — what most people casually call pest control. But she wants to do it differently. She has seen the conventional approach: show up, spray poison, send a bill, repeat when the problem comes back. She wants to understand the biology. She wants to know why the pest is there, what it is eating, where it is breeding, and what will make it stop. She wants to solve problems, not just treat symptoms.

This module follows Maya as she learns the science, history, and emerging technologies of nuisance species management. Along the way, you will learn about the biology and behavior of common pests, the ancient wisdom of civilizations that managed nature without synthetic chemicals, the devastating unintended consequences of modern poisons, and the cutting-edge technologies that are redefining what is possible in this field.

This is not just about bugs. This is about understanding ecosystems — and your place in them.

PART 2: THE OLDEST PROFESSION YOU NEVER HEARD OF — 5,000 YEARS OF PEST MANAGEMENT

Humans have been managing nuisance species since the dawn of agriculture. The moment we started storing grain, nature showed up to eat it. The strategies our ancestors developed were remarkably sophisticated — and many are still relevant today.

Ancient Egypt (circa 3000 BCE)

The ancient Egyptians were among the earliest civilizations to practice organized pest management. They discovered that domesticated cats were exceptionally effective at controlling rodent populations in grain storage facilities. This was not an accident — cats were specifically valued for their hunting ability, and their importance in Egyptian society was reflected in the reverence afforded to the cat-headed goddess Bastet. The Egyptians also used aromatic plant extracts and oils to repel insects from stored grain, and they developed rudimentary traps and water barriers to keep rodents away from food supplies.

Ancient Sumeria (circa 2500 BCE)

The Sumerians of Mesopotamia produced the earliest known record of chemical pest control. They discovered that sulfur compounds could repel and kill insects and mites that damaged their crops. Sulfur fumigation — burning sulfur to produce toxic fumes — would remain a standard pest control technique for thousands of years and is still used in modified forms today.

Ancient China

Chinese farmers developed one of history’s most elegant biological control strategies: they used predatory ants to protect citrus orchards from destructive insects. Workers would place bamboo bridges between citrus trees to help the ants move between canopies, creating a living, self-sustaining pest control system that required no chemicals at all. Chinese agriculture also pioneered seasonal crop rotation and companion planting to disrupt pest life cycles.

Ancient Greece and Rome

Greek and Roman farmers contributed several techniques still recognizable today. The Greeks spread wood ash on cropland as an insect deterrent — a practice some organic gardeners still use. Homer himself described smoke being used to drive away locusts. The Romans developed amurca, a paste made from crushed olives and salt, as an early pesticide effective against ants. Perhaps most importantly, the Romans understood the connection between sanitation and pest problems. They enforced cleanliness codes for water supplies and public areas — an insight that would be largely forgotten in Europe after the fall of Rome, with catastrophic consequences.

The Medieval Lesson

When Roman sanitation practices collapsed in medieval Europe, rodent and flea populations exploded. The result was the Black Death — the bubonic plague, spread by fleas carried on rats — which killed approximately one-third of Europe’s population in the 14th century. Rat catchers became a recognized profession, armed with little more than sticks, planks, and determination. Queen Elizabeth I eventually decreed that public areas must be kept clean — a return to the Roman insight that sanitation is the first line of defense against pests.

The lesson across all of these civilizations is consistent: the most effective pest management starts with understanding why the pest is there and removing the conditions that support it. Poison was always a last resort — not because ancient peoples were sentimental, but because they observed that prevention was more reliable, more sustainable, and less dangerous than chemical warfare against nature.

QUESTION 1

Choose one ancient civilization’s pest management approach described above. (a) Describe what they did. (b) Explain why it worked based on what you understand about pest biology and behavior. (c) Could this approach be adapted for use today? If so, how? If not, why not?

Your Answer:

HINT: Think about whether the approach addresses the root cause (food, shelter, access) or just the symptom (visible pests). The best ancient methods did both.

PART 3: INTEGRATED PEST MANAGEMENT — THE PHILOSOPHY THAT CHANGES EVERYTHING

Integrated Pest Management — commonly abbreviated as IPM — is the modern framework that formalizes what Maya’s grandmother understood intuitively. The U.S. Environmental Protection Agency defines IPM as an effective, environmentally sensitive approach to pest management that uses current, comprehensive information on the life cycles of pests and their interaction with the environment to manage pest damage by the most economical means and with the least possible hazard to people, property, and the environment.

IPM is not anti-chemical. It is anti-lazy. It insists on answering a question before reaching for a spray can: Why is this pest here?

The IPM Decision Ladder

IPM follows a logical sequence, and each step should be exhausted before moving to the next:

Notice that chemical control is Step 7, not Step 1. The conventional pest control industry often inverts this order — spray first, ask questions later. IPM insists on doing it right: diagnose the problem, address the root cause, and escalate only as needed.

Why does this matter? Because when you spray poison as your first response, several things happen. The pest population may temporarily decrease, but the conditions that attracted them remain unchanged. Survivors that are naturally resistant to the chemical pass on their resistance to the next generation. Non-target organisms — including beneficial insects, pets, and wildlife — are harmed. And the customer calls you back in three months because the problem returned. You treated the symptom, not the disease.

QUESTION 2

Maya inspects a customer’s kitchen and finds cockroaches. The customer says, “Just spray everything.” Using the IPM Decision Ladder above, walk through what Maya should do instead, step by step. Why might her approach take longer initially but save the customer money in the long run?

Your Answer:

HINT: Think about what attracts cockroaches: moisture, food debris, warmth, and dark hiding places. If you spray but do not fix the leaking pipe under the sink, what happens next month?

PART 4: KNOW YOUR ENEMY — BED BUGS AND THE BIOLOGY OF AN INVISIBLE INVADER

If there is one pest that perfectly illustrates why biology matters more than chemicals, it is the bed bug (Cimex lectularius). Bed bugs have made a dramatic global resurgence over the past two decades, and their success is a direct result of their remarkable biology.

Biology and Life Cycle

Bed bugs are small, flat, reddish-brown insects approximately the size of an apple seed. They are obligate blood feeders — meaning they must feed on blood (typically human) to survive and reproduce. They are nocturnal and are attracted to the carbon dioxide and body heat that sleeping humans produce. A single female can lay 200 to 500 eggs in her lifetime. Eggs hatch in approximately 6 to 10 days. Nymphs (juveniles) must take a blood meal between each of their five molts before reaching adulthood. The entire life cycle from egg to reproductive adult can be completed in as little as five weeks under favorable conditions.

Why They Are So Hard to Eliminate

Bed bugs hide in cracks and crevices near sleeping areas during the day: mattress seams, box spring interiors, bed frame joints, headboard crevices, nightstand drawers, electrical outlet covers, and even behind peeling wallpaper. They are flat enough to fit into gaps the width of a credit card. They can survive for months without feeding. And critically, many populations have developed significant resistance to pyrethroid insecticides — the most commonly used class of chemicals for indoor pest control.

This resistance is not theoretical. Research has documented bed bug populations that can tolerate pyrethroid concentrations more than 1,000 times the dose that would kill susceptible populations. The bugs accomplish this through multiple mechanisms: thickened outer cuticles that reduce chemical penetration, metabolic enzymes that break down pesticides internally, and nerve cell mutations that make the target site less sensitive to the chemical.

The Psychology of Bed Bugs

Understanding bed bug behavior is as important as understanding their biology. Bed bugs are thigmotactic — they prefer to be in contact with surfaces on multiple sides of their body, which is why they wedge themselves into tight crevices. They navigate using chemical cues: aggregation pheromones attract them to harborage sites where other bed bugs are present, while alarm pheromones cause them to scatter when disturbed. When a room is treated with a repellent chemical, bed bugs do not die — they scatter to neighboring rooms, spreading the infestation.

This is why foggers (bug bombs) are specifically not recommended for bed bugs. Cornell University’s bed bug guidance states that total-release foggers place pesticide where it should not go and are ineffective for bed bug control. The chemical mist does not penetrate the crevices where bed bugs hide, and the repellent effect drives bugs deeper into walls and into adjacent units.

The Human Cost

Bed bugs generally do not transmit diseases, but their impact on human well-being can be severe. Bites cause itching, inflammation, and secondary infections from scratching. The psychological toll — insomnia, anxiety, social stigma, and the feeling of being violated in one’s own bed — can be devastating. Many people throw away mattresses, furniture, and clothing in a panic, suffering thousands of dollars in financial losses. The social stigma is especially cruel because bed bug infestations are not caused by uncleanliness. They are hitchhikers that can be picked up in hotels, airports, movie theaters, public transit, and office buildings. Anyone can get them.

QUESTION 3

(a) Why are bed bugs resistant to many common insecticides? Name at least two biological mechanisms.

(b) Why do foggers (bug bombs) often make a bed bug problem worse instead of better?

(c) A person tells you they are embarrassed about having bed bugs and thinks it means their home is dirty. How would you respond?

Your Answer:

HINT: Think about the word “thigmotactic” and what it means for where bugs hide. Consider that bed bugs are obligate blood feeders — they need YOU, not your crumbs.

PART 5: HEAT, COLD, AND FUNGUS — THE NEW ARSENAL AGAINST BED BUGS

If chemicals alone cannot solve the bed bug problem, what can? The answer lies in physics and biology.

Heat Treatment

Bed bugs at all life stages — eggs, nymphs, and adults — die when exposed to sustained temperatures above approximately 120°F to 125°F (49°C to 52°C). Professional heat treatment involves bringing an entire room or structure to lethal temperatures using industrial heaters and fans, typically holding the temperature above 130°F for several hours to ensure heat penetrates into wall voids, furniture, and other harborage areas.

Heat treatment has several advantages over chemicals: it kills all life stages including eggs, it penetrates into areas that sprays cannot reach, bed bugs cannot develop resistance to high temperatures (you cannot evolve your way out of physics), and no chemical residue is left behind. The primary disadvantages are cost (professional heat treatment can run $1,000 to $3,000+ per treatment), the need for specialized equipment, and the risk of heat damage to sensitive items like electronics, vinyl records, or candles.

Cryonite Freezing

On the opposite end of the temperature spectrum, Cryonite technology uses pressurized carbon dioxide (CO₂) snow — reaching temperatures as low as approximately -110°F (-79°C) — to kill bed bugs through rapid cellular freezing. The CO₂ snow is applied directly to infested areas through a specialized nozzle. When the dry ice snow contacts a bed bug, the extreme cold causes the water inside the insect’s cells to crystallize into ice, killing it on contact. The CO₂ then evaporates into gas, leaving no chemical residue, no moisture, and no odor.

Cryonite is particularly valuable in sensitive environments — hospitals, food preparation areas, data centers, and homes with children or pets — where chemical treatments are undesirable or impractical. Because it is a physical mechanism of death (freezing), bed bugs cannot develop resistance to it. However, Cryonite requires direct contact with the bugs, so it is most effective as part of an integrated approach rather than a standalone solution.

Entomopathogenic Fungi: The Biological Weapon

One of the most exciting developments in bed bug control is the use of entomopathogenic fungi — fungi that specifically infect and kill insects. The biopesticide Aprehend, registered by the EPA in 2017, uses spores of the naturally occurring fungus Beauveria bassiana in an oil-based formulation. The spores are sprayed in thin barriers along surfaces where bed bugs travel. When a bed bug walks across the barrier, the microscopic spores adhere to its legs and body. The bug carries the spores back to its harborage, where they spread to other bed bugs through direct contact.

Within 4 to 10 days, the fungal spores germinate, penetrate the bed bug’s exoskeleton, and grow inside the insect, killing it from within. The beauty of this approach is its self-spreading mechanism: a single infected bed bug becomes a vector that carries the biological agent into the very crevices where the colony hides — places that sprays and even heat may not fully reach. The residual barrier remains effective for up to three months. Bed bugs are unlikely to develop resistance to a living pathogenic organism the way they can to a chemical.

Research published in the journal Insects found that Aprehend remained effective even when applied over residues of previously applied chemical insecticides, and in some cases, the combination of fungal and chemical agents enhanced overall efficacy.

Steam

Commercial steam units can deliver steam at temperatures above 200°F directly into mattress seams, box spring interiors, and furniture crevices. Like heat treatment, steam kills through thermal transfer and leaves no residue. However, steam introduces moisture, which must be managed to prevent mold growth. Steam is best used as a targeted tool within a broader IPM strategy.

Diatomaceous Earth (With Caution)

Diatomaceous earth (DE) is a naturally occurring powder made from fossilized algae (diatoms). The microscopic particles have sharp edges that damage the waxy outer layer of an insect’s exoskeleton, causing it to lose moisture and die from dehydration. DE is non-toxic if ingested by humans or pets. However — and this is critical — DE is dangerous if inhaled. The fine particles can cause respiratory irritation and, with prolonged exposure, contribute to silicosis, a serious lung condition. Always use respiratory protection when applying DE, and never use pool-grade DE (which is chemically different and far more hazardous) for pest control.

QUESTION 4

A customer has a severe bed bug infestation in a small apartment. They have a pet cat, a young child, and a limited budget.

(a) Which of the methods described above would you consider combining, and why?

(b) Which methods would you avoid for this particular customer, and why? 

(c) Why is an integrated approach using multiple methods typically more effective than relying on any single method alone?

Your Answer:

HINT: Think about the customer’s specific constraints: a cat and child mean chemical safety matters. A limited budget may rule out whole-room heat treatment. Bed bugs hide in places that require different tools to reach.

PART 6: RODENTS — MAMMALS WITH A STRATEGY

Rats and mice are not insects. They are highly intelligent mammals with complex social behaviors, excellent memories, and an ability to adapt to almost any human environment. Understanding them as mammals — not as oversized bugs — is the key to effective management.

Biology and Behavior

Norway rats (Rattus norvegicus) are cautious, territorial, and neophobic — they fear new objects in their environment. This is why snap traps sometimes fail: the rat sees a new object in its path and avoids it for days or weeks. Successful trapping often requires placing unset, baited traps for several days to let rats acclimate to their presence before setting them. House mice (Mus musculus), by contrast, are curious and will investigate new objects quickly, making them easier to trap but harder to keep out because they will explore every gap and crack.

A female mouse can produce 5 to 10 litters per year, with 5 to 6 pups per litter. A single breeding pair can theoretically produce hundreds of descendants in a year. This exponential reproduction means that killing individual mice without addressing the underlying conditions (entry points, food access, harborage) is mathematically futile.

Exclusion: The Real Solution

A mouse can squeeze through a gap as small as a quarter-inch — roughly the diameter of a pencil. A rat can fit through a half-inch opening. Exclusion — physically sealing every potential entry point with steel wool, copper mesh, concrete, or metal flashing — is the most effective long-term rodent control strategy. Combined with rigorous sanitation (securing food in sealed containers, removing food waste promptly, eliminating water sources), exclusion addresses the root cause rather than endlessly chasing the symptoms.

Maya’s grandmother understood this instinctively: seal the gap, remove the food, and the mice leave. No poison required.

The Humane Trap Debate

Glue traps are widely condemned by animal welfare organizations as inhumane. A mouse stuck on a glue trap can suffer for hours or days before dying of exhaustion, dehydration, or self-inflicted injuries from trying to escape. Some jurisdictions have banned or restricted glue traps. Snap traps, when properly set and positioned, provide a rapid death. Live-catch traps allow for relocation, though rodents released in unfamiliar territory have very low survival rates — which raises its own ethical questions.

The most humane approach is always prevention: make it so the rodent never enters in the first place.

QUESTION 5

(a) Why is a mouse’s rapid reproduction rate relevant to pest management strategy? 

(b) Explain why exclusion and sanitation are more effective long-term rodent control methods than poisons.

(c) What is neophobia, and how does it affect trapping strategies for rats versus mice?

Your Answer:

HINT: If a single pair of mice can produce hundreds of offspring per year, what happens if you kill 10 mice but leave the entry point open?

PART 7: THE POISON CHAIN — HOW RAT POISON KILLED A MOUNTAIN LION

This section is about unintended consequences — and why the decision to use chemical rodenticides should never be taken lightly.

The Case of P-47

In March 2019, National Park Service biologists recovered the body of P-47, a three-year-old male mountain lion, in the Santa Monica Mountains of California. He had no visible wounds. A necropsy — the animal equivalent of an autopsy — conducted by the California Animal Health and Food Safety Lab found massive internal hemorrhaging in his head and lungs. Testing of his liver revealed six different anticoagulant rodenticide compounds: brodifacoum, bromadiolone, chlorophacinone, difethialone, diphacinone, and difenacoum. He had been poisoned not by eating rat bait directly, but through the food chain.

Mountain lions eat coyotes and other medium-sized predators. Coyotes eat ground squirrels and other small mammals. Small mammals eat rodent bait. At each step up the food chain, the poison concentrates. This is called secondary or tertiary poisoning, and it is devastating to predators at the top of the food web.

The Scope of the Problem

P-47 was not an isolated case. NPS researchers have documented the presence of anticoagulant rodenticide compounds in the vast majority of local mountain lions they have tested — including a three-month-old kitten. In a 2024 California statewide survey, anticoagulant rodenticides were found in 95 percent of mountain lions and 69 percent of all non-target wildlife tested. The EPA has found that these poisons are threatening at least 78 endangered species nationwide, including California condors, Florida panthers, and black-footed ferrets.

The irony is bitter: anticoagulant rodenticides may not even be effectively controlling rodent populations. Natural predators — hawks, owls, coyotes, bobcats, foxes — are nature’s rodent control system. By poisoning these predators, we remove the very species that would otherwise keep rodent populations in check, creating a cycle where more poison leads to fewer predators leads to more rodents leads to more poison.

How Anticoagulant Rodenticides Work

Anticoagulant rodenticides work by blocking the enzyme vitamin K epoxide reductase, which is essential for blood clotting. Without functional clotting factors, the animal bleeds internally and eventually dies. First-generation anticoagulants (like warfarin) require multiple feedings and have shorter half-lives. Second-generation anticoagulants (SGARs) like brodifacoum are far more potent — a single feeding can be lethal — and they persist in the liver for months, which is exactly why they are so dangerous to predators that eat poisoned prey.

QUESTION 6

(a) Explain secondary poisoning in your own words. Use the mountain lion example to illustrate the food chain pathway.

(b) Why might killing natural predators with rodenticides actually make a rodent problem worse over time?

(c) If a customer asks you to put out rodent poison near their barn, and you know there are owls and hawks in the area, what would you recommend instead?

Your Answer:

HINT: Think about what happens to a food chain when you remove the top predators. Also think about the word “secondary” — the mountain lion is not eating the poison directly.

PART 8: BARN CATS, BAT HOUSES, AND THE ART OF BIOLOGICAL DETERRENCE

Before chemicals, humans managed pests by working with nature. Many of these strategies are not only still effective — they are often more effective, more sustainable, and less expensive than chemical alternatives.

Cats as Rodent Deterrents

Barn cats have been used for rodent control for thousands of years, and the science behind their effectiveness goes beyond direct predation. Research has shown that the scent of cat urine can deter rodents from an area even when no cat is physically present. The mere presence of a predator’s chemical signature triggers avoidance behavior in prey species. That said, cats are not a complete rodent control program — they are a supplemental deterrent that works best alongside exclusion and sanitation.

Bat Houses for Insect Control

A single little brown bat can consume 600 to 1,000 mosquito-sized insects per hour. Installing bat houses on a property provides natural, ongoing, no-cost insect control. Bats are especially valuable for controlling moths, beetles, and flies in agricultural settings. Many state wildlife agencies provide free bat house plans and installation guidance.

Barn Owls and Raptors

A family of barn owls can consume 3,000 or more rodents in a single nesting season. The Hungry Owl Project and similar programs distribute nest boxes to farms, vineyards, and rural properties to encourage barn owl populations as a natural rodent control alternative. Hawks and other raptors provide similar services. This is one of the strongest arguments against anticoagulant rodenticides: by poisoning the rodents that raptors eat, you kill your most effective allies.

Companion Planting and Trap Crops

In agriculture, companion planting uses the properties of certain plants to repel pests from neighboring crops. Marigolds, for example, produce compounds that repel nematodes and many insect species. Basil planted near tomatoes can repel aphids and whiteflies. Trap crops work on the opposite principle: you plant something that pests prefer even more than your cash crop, drawing them away from the plants you want to protect. A border of mustard plants, for instance, can lure flea beetles away from a cabbage field.

Visual and Auditory Deterrents

Reflective tape, holographic streamers, and fake predator decoys (owl statues, hawk silhouettes) can deter birds and some mammals through visual confusion and fear responses. Fladry — lines of hanging fabric strips — has been used for centuries in Europe to direct wolves away from livestock and is now being studied for use with feral hogs. The limitation of all visual deterrents is habituation: animals are intelligent and will eventually learn that the fake owl is not real. Effective use requires regularly moving and varying deterrent types.

Neem Oil

Neem oil, extracted from the seeds of the neem tree (Azadirachta indica), has been used as a natural insect repellent in India for thousands of years. It contains azadirachtin, a compound that disrupts insect feeding, molting, and reproduction. While less acutely toxic than synthetic insecticides, neem oil is not completely harmless — it can affect beneficial insects if applied carelessly, and it should be used according to label instructions like any pest control product.

QUESTION 7

Maya is helping a small organic farm that is losing lettuce crops to slugs and aphids, and also has a mouse problem in the barn. The farm does not want to use any synthetic chemicals.

(a) Design an integrated management plan that uses at least three biological or natural methods from this section.

(b) For each method, explain what it targets and why it is appropriate for this situation. 

(c) What are the limitations of relying entirely on natural methods?

Your Answer:

HINT: Slugs are deterred by copper barriers and attracted to beer traps. Aphids are eaten by ladybugs and lacewings, which are attracted by flowering plants like yarrow and dill. Mice in barns are deterred by cats and excluded by sealing gaps.

PART 9: FERAL HOGS — AMERICA’S SIX-MILLION-STRONG INVASIVE ARMY

Feral hogs (Sus scrofa) may be the most destructive invasive species in the United States. With an estimated population of over six million animals spread across at least 35 states, they cause an estimated $1.5 billion to $2.5 billion in damage annually to crops, livestock, native wildlife, property, and ecosystems. They are smart, prolific, adaptable, and nearly impossible to control with conventional methods.

Origin and Biology

Feral hogs are descendants of domestic pigs brought to North America by Spanish explorers in the 1500s, crossed with Eurasian wild boars imported for sport hunting in the early 1900s. They are omnivores that will eat virtually anything: crops, acorns, roots, grubs, bird eggs, small mammals, reptiles, and even deer fawns. A single sow can produce two litters per year, with 4 to 12 piglets per litter. This reproductive rate means that wildlife managers must remove at least 70 percent of a feral hog population annually just to prevent growth.

An adult male can weigh 200 to 500 pounds. Their rooting behavior — using powerful snouts to dig up soil in search of food — devastates agricultural fields, destroys native plant communities, accelerates erosion, contaminates water sources, and damages levees and infrastructure. One farmer in Mississippi reported losing 40 to 60 acres of corn and soybeans annually to feral hogs.

Why Traditional Methods Are Failing

Hunting alone cannot control feral hog populations. Hogs are primarily nocturnal, highly wary, and learn quickly. A sounder (social group) that has been shot at will change its behavior, becoming harder to locate and more cautious. Trapping entire sounders using corral-style traps with remote-triggered gates is currently the most effective removal method, because it removes multiple animals simultaneously. Removing only a few members of a sounder allows the remaining animals to reproduce and quickly replenish their numbers.

Emerging Chemical Tools: Sodium Nitrite

Researchers at the USDA’s National Wildlife Research Center have been developing a sodium nitrite-based toxic bait specifically for feral swine. Sodium nitrite is a common food preservative (it is used to cure bacon and sausages), but when consumed in large amounts over a short period, it causes methemoglobinemia — a condition where blood can no longer carry oxygen. The mode of death is similar to carbon monoxide poisoning: the animal becomes disoriented, loses consciousness, and dies, typically within 2.5 to 3 hours.

Pigs are uniquely vulnerable because they produce very low levels of the enzyme (methemoglobin reductase) that counteracts sodium nitrite. Humans and most other mammals produce much higher levels of this protective enzyme, which is one reason sodium nitrite is considered relatively species-specific. The bait is delivered through specially designed hog-specific feeding stations that require an animal to use its snout to lift a heavy lid — a behavior that raccoons, deer, and most other non-target species cannot replicate.

However, the EPA has not yet approved sodium nitrite for widespread operational use against feral swine in the United States. Field trials have revealed challenges: the bait can crumble during consumption, allowing fragments to fall to the ground where non-target species might access them. Researchers are working on improving the bait formulation — making it the consistency of gummy bears, as one LSU researcher described it — to ensure hogs consume a full lethal dose without dropping pieces.

The Warfarin Controversy

In 2017, Texas approved a warfarin-based feral hog toxicant called Kaput, which uses a low-dose blood thinner to cause fatal hemorrhaging. The product was controversial from the start: concerns about non-target exposure, environmental contamination, and the slow death the product causes led to its registration being temporarily revoked within weeks. As of this writing, research on warfarin-based hog toxicants continues, but the regulatory and public acceptance hurdles remain significant.

Whole-Animal Utilization

One creative approach to the feral hog problem is to create economic incentives for removal by maximizing the value of harvested animals. Feral hog meat can be processed for human consumption (it must be inspected by USDA or state authorities), organ meats can feed humans and animals, hides can be tanned into leather, bristles can be used for brushes, and connective tissues can be processed into animal-grade adhesives. Creating a market for feral hog products could help offset the cost of removal and incentivize more aggressive harvesting.

QUESTION 8

(a) Why must at least 70% of a feral hog population be removed each year just to prevent growth? What does this tell you about their reproductive biology?

(b) The sodium nitrite bait uses specially designed feeders that require a snout to open. Why is the design of the delivery system as important as the toxicant itself? 

(c) Propose one way that communities could create economic incentives to encourage feral hog removal. Think creatively.

Your Answer:

HINT: Think about the concept of exponential growth. If a sow produces 8 to 24 piglets per year, and half of those are female, and those females can breed within a year... the math gets very large very fast.

PART 10: WHEN WOLVES CHANGED THE RIVERS — THE YELLOWSTONE TROPHIC CASCADE

In 1995, after a 70-year absence, gray wolves (Canis lupus) were reintroduced to Yellowstone National Park. What happened next is one of the most remarkable ecological stories of the modern era — and it carries profound lessons for anyone in the field of nuisance species management.

Before the Wolves

When wolves were eliminated from Yellowstone in the 1920s, the elk population exploded. Without their primary predator, elk herds grew unchecked and stopped moving. They browsed heavily on young willow, aspen, and cottonwood trees, particularly along rivers and streams, eating seedlings down to stumps. Without tree roots to stabilize the banks, rivers widened and eroded. Songbird populations declined because there were no trees for nesting. Beaver colonies collapsed from a recorded 25 colonies in 1921 to roughly 6 by the 1950s because their food and dam-building materials had been consumed by the overbrowsing elk.

After the Wolves

When wolves returned, they did not simply reduce the elk population — they changed elk behavior. Elk could no longer safely lounge in river valleys eating everything in sight. The threat of predation forced them to move, to be vigilant, to avoid certain areas. Ecologists call this a “landscape of fear” — the wolves’ mere presence changed where elk would and would not go.

The results cascaded through the entire ecosystem. Willows and aspens began to recover. A 20-year study found a roughly 1,500 percent increase in average willow crown volume. Songbirds returned to nest in the regrowing trees. Beaver colonies expanded from 1 to eventually over 85 documented colonies. Beaver dams slowed stream flow, recharged water tables, provided cold shaded water for fish, and created new habitat for amphibians, reptiles, and otters. Grizzly bears benefited from both wolf-killed elk carcasses and the regrowth of berry-producing shrubs. Even the physical course of rivers began to change as stabilized banks narrowed the channels.

Meanwhile, wolves also reduced coyote populations by approximately 80 percent in areas they occupied. Fewer coyotes meant more small rodents survived, which provided food for raptors like eagles, hawks, and ospreys.

The Lesson for Pest Management

The Yellowstone story is a powerful illustration of a trophic cascade — the principle that changes at the top of a food chain ripple all the way down to the bottom. It demonstrates that removing a single species from an ecosystem can have consequences that take decades to manifest, and that restoring that species can trigger a chain of recovery that touches virtually every other organism in the system.

For anyone in nuisance species management, the lesson is this: you are not just managing one pest. You are intervening in an ecosystem. Every action you take — every poison you deploy, every predator you remove, every habitat you alter — has consequences beyond the immediate target. The professional who understands ecology will make better decisions than the one who only understands chemicals.

QUESTION 9

(a) In your own words, explain what a trophic cascade is, using the Yellowstone wolf example.

(b) How did the wolves change elk behavior even beyond reducing elk numbers? What is a “landscape of fear”?

(c) What parallel can you draw between the Yellowstone story and the mountain lion rodenticide poisoning case from Part 7?

Your Answer:

HINT: Both cases involve food chain effects. In one case, removing a top predator damaged the ecosystem from the top down. In the other case, poison placed at the bottom of the food chain damaged it from the bottom up.

PART 11: LIVING IN HARMONY — BEAVERS, GEESE, AND THE CASE FOR COEXISTENCE

Beavers: Nature’s Engineers

In early 2025, the Czech government had spent seven years and $1.2 million planning a dam project to restore wetlands south of Prague. The project was stuck in bureaucratic delays. Then eight beavers showed up and did the job in a matter of weeks — for free. The beaver-built dams created a thriving wetland that provided habitat for rare crayfish, frogs, and aquatic insects. “They built the dams without any project documentation and for free,” said the head of the local protected landscape area. Scientists estimate the beavers saved Czech taxpayers approximately $1.2 million.

Beavers are frequently viewed as nuisance animals because their dams flood areas that humans want dry. But beaver wetlands provide enormous ecological services: they filter pollutants, recharge groundwater, reduce downstream flooding, provide fire breaks during droughts, and create habitat for hundreds of other species. The solution is often not removal but conflict reduction — flow devices that limit water levels while preserving the dam, and tree guards that protect valuable trees while allowing beavers to harvest others.

Canada Geese

Canada geese can be a significant nuisance in parks, golf courses, and corporate campuses, fouling lawns and sidewalks with droppings and occasionally becoming aggressive. However, they are protected under the Migratory Bird Treaty Act, and in many jurisdictions it is illegal to harm them, disturb their nests, or destroy their eggs without a federal permit. Humane deterrence options include trained herding dogs (Border Collies are particularly effective at convincing geese that an area is not safe), habitat modification (allowing grass to grow tall near shorelines, which geese dislike because it blocks their sightlines), and egg addling programs conducted under federal permit.

Feral Cats and TNR

Feral cat colonies are a contentious issue. Cats are effective predators of rodents and other small animals, but they also prey on birds and can carry diseases. Trap-and-euthanize programs are both emotionally distressing and often ineffective: when cats are removed from a territory, new cats from surrounding areas move in to fill the vacancy. This is called the vacuum effect.

Trap-Neuter-Vaccinate-Return (TNVR) programs take a different approach. Feral cats are trapped, spayed or neutered, vaccinated against rabies, ear-tipped for identification, and returned to their territory. The existing colony cannot reproduce, but it continues to occupy the territory and repel newcomers. Over time, the colony size naturally declines through attrition. TNVR does not instantly solve the problem, but evidence suggests it is the most effective long-term strategy for humanely managing feral cat populations in most urban and suburban settings.

When Coexistence Is the Answer

Not every wildlife encounter requires intervention. Opossums eat ticks. Bats eat mosquitoes. Snakes eat rodents. Spiders eat flies. Many “nuisance” animals are actually providing valuable pest control services. The professional who understands ecology knows when to manage, when to deter, and when to simply leave the animal alone and explain its value to the customer.

QUESTION 10

Think about a time when you encountered an animal that most people would consider a nuisance — a spider, a snake, a stray cat, a raccoon, a colony of ants. 

(a) What was the animal doing, and why was it there? 

(b) Was it actually causing harm, or was it simply present?

(c) If you were a professional called to handle the situation, what would you recommend?

Your Answer:

HINT: The question is not “Is this animal inconvenient?” but “Is this animal causing actual damage, and if so, is there a way to resolve the conflict without removing or harming it?”

PART 12: THE FUTURE — GENE DRIVES, CRYONITE, AND FUNGAL BIOPESTICIDES

The technologies emerging in nuisance species management today would have seemed like science fiction a generation ago.

Gene Drives

A gene drive is a genetic engineering technique that can cause a particular gene to spread through a population faster than normal inheritance would allow. In theory, a gene drive could be used to spread a sterility gene through an invasive species population, causing it to decline over generations without the use of any poison. Research is ongoing on gene drives for invasive rodents on islands, mosquitoes that carry malaria, and other target species. The technology is extraordinarily powerful — and extraordinarily controversial, because a gene drive released into a wild population could be difficult or impossible to recall if something goes wrong.

AI and Sensor Networks

Modern pest management is increasingly using technology: camera traps with AI-powered species identification, acoustic monitors that can detect rodent movement inside walls, drone-based thermal imaging for locating feral hog sounders, and smart trap systems that send a notification to your phone when they activate. The pest management professional of the future may spend as much time interpreting data as applying treatments.

Wildlife Contraceptives

Chemical contraceptives and immunocontraceptive vaccines are being developed for several species, including feral horses, white-tailed deer, and (experimentally) feral swine. The idea is to suppress reproduction in a target population without lethal removal. The primary challenges are delivery (how do you dose a wild animal?), duration (most contraceptives require repeated doses), and cost.

Insect Growth Regulators (IGRs)

Insect growth regulators are chemicals that mimic or disrupt insect hormones, preventing juveniles from maturing into reproductive adults. They do not kill adult insects directly; instead, they break the reproductive cycle. IGRs are highly targeted — they affect insects but generally not mammals, birds, or fish — and are increasingly used in combination with other IPM methods for long-term management of cockroaches, fleas, and bed bugs.

Every technology discussed in this section is either experimental, partially deployed, or evolving rapidly. The student who pays attention to these developments will be prepared for the profession that exists five years from now, not just the one that exists today.

QUESTION 11

(a) What is a gene drive, and why is it both exciting and concerning as a pest management tool?

(b) How might artificial intelligence change the day-to-day work of a pest management professional?

(c) Choose one emerging technology from this section and explain how it could complement (not replace) the IPM Decision Ladder from Part 3.

Your Answer:

HINT: Think about the word “complement.” The best emerging technologies do not replace the fundamentals — they enhance them. You still need to identify, monitor, and prevent before intervening.

PART 13: THE BIG PICTURE — YOU ARE NOT JUST REMOVING PESTS

Step back and look at what Maya has learned. She understands why pests are present, not just what they are. She can trace the food chain from a rat bait station to a dying mountain lion. She knows that ancient Egyptians used cats, ancient Chinese used ants, and modern researchers are engineering fungi to fight bed bugs. She can design an IPM plan that starts with prevention and ends with targeted, least-toxic intervention. She can explain trophic cascades to a farmer and TNVR to a city council.

These are not just exterminator skills. These are the skills of an ecologist, a public health professional, a community problem-solver, and a scientific thinker. The person who understands why cockroaches thrive in a building understands moisture, ventilation, sanitation, and building maintenance. The person who understands feral hog biology understands population dynamics, invasive species ecology, and agricultural economics. The person who understands the Yellowstone wolf story understands how entire ecosystems are connected in ways that are invisible until something goes wrong.

This field is about solving problems that other people do not want to deal with. That is a public service. It takes courage, knowledge, and professionalism. And it takes empathy — empathy for the customer whose home has been invaded, empathy for the ecosystems you are managing, and yes, even empathy for the animals you are tasked with controlling.

The best professionals in this field do not enjoy killing things. They take no pleasure in it. They do what is necessary, as humanely as possible, and they work to prevent the conditions that made the intervention necessary in the first place. That is the mark of a true professional.

PART 14: RESOURCES FOR FURTHER LEARNING AND PROFESSIONAL DEVELOPMENT

The following organizations and programs can help you continue learning and pursue professional credentials in pest management and wildlife services.

Professional Organizations

Certifications to Explore

State Pesticide Applicator License (required in all states; contact your state Department of Agriculture)

NPMA Pro Certified (national pest management certification)

Associate Certified Entomologist (ACE) through the Entomological Society of America

Certified Wildlife Control Professional through NWCOA

EPA Section 608 Certification (refrigerant handling, for HVAC crossover)

QualityPro Certification (NPMA business and service standards)

PART 15: KEY VOCABULARY

Anticoagulant Rodenticide: A class of poisons that kill by preventing blood clotting, causing internal hemorrhaging. Can persist in the food chain and poison non-target predators.

Beauveria bassiana: A naturally occurring entomopathogenic fungus used as a biological control agent against insects, including bed bugs.

Biological Control: The use of living organisms (predators, parasites, pathogens) to manage pest populations.

Cryonite: A pest control technology that uses pressurized CO₂ snow to freeze and kill insects on contact without chemicals.

Entomopathogenic: Causing disease in insects. Entomopathogenic fungi infect insects through their exoskeletons.

Exclusion: The practice of physically sealing entry points to prevent pests from accessing a structure.

Gene Drive: A genetic engineering technique that causes a modified gene to spread through a population faster than normal inheritance.

Habituation: The process by which animals become accustomed to a deterrent and stop responding to it.

Insect Growth Regulator (IGR): A chemical that disrupts insect development, preventing juveniles from maturing into reproductive adults.

Integrated Pest Management (IPM): A systematic approach to pest management that prioritizes prevention and uses chemical control as a last resort.

Methemoglobinemia: A condition in which blood loses its ability to carry oxygen. The mechanism by which sodium nitrite kills feral swine.

Neophobia: Fear of new objects. A behavioral trait in Norway rats that complicates trapping efforts.

Secondary Poisoning: When a predator is poisoned by consuming prey that has ingested a toxicant.

Sounder: A social group of feral hogs, typically consisting of related females and their offspring.

Thigmotaxis: The tendency of an organism to seek contact with surfaces. Explains why bed bugs wedge into crevices.

TNVR: Trap-Neuter-Vaccinate-Return. A humane strategy for managing feral cat colonies.

Trophic Cascade: A chain of ecological effects triggered by changes at the top of a food chain that ripple down to lower levels.

Vacuum Effect: When removal of animals from a territory causes surrounding animals to move in and fill the vacated space.

SOURCES AND REFERENCES

The following sources were referenced in the creation of this module. Web links are provided where available for instructors and program coordinators. Learners who do not have internet access can reference these citations for further study upon release.

1. EPA. “Integrated Pest Management (IPM) Principles.” epa.gov/safepestcontrol/integrated-pest-management-ipm-principles

2. Cornell University. “Managing Bed Bugs.” cals.cornell.edu

3. NC State Extension. “Bed Bugs: Biology and Control.” content.ces.ncsu.edu

4. National Park Service. “Mountain Lion Found Dead, Poison Suspected.” nps.gov/samo (P-47, P-41, P-76, P-54 case reports)

5. Center for Biological Diversity. “New California Report: Rat Poisons Still Causing Widespread Harm to Wildlife.” biologicaldiversity.org (November 2024)

6. USDA APHIS. “Sodium Nitrite Toxic Bait for Feral Swine.” aphis.usda.gov

7. USDA APHIS. “Feral Swine Damage Management.” aphis.usda.gov/wildlife-damage

8. Texas A&M AgriLife Extension. “Coping with Feral Hogs: Chemical Control.” feralhogs.tamu.edu

9. LSU AgCenter. “LSU Working on Way to Kill Hogs Humanely.” laforestry.com (October 2021)

10. Ripple, W.J. et al. “The Strength of the Yellowstone Trophic Cascade After Wolf Reintroduction.” ScienceDirect (January 2025)

11. National Geographic Education. “Wolves of Yellowstone.” education.nationalgeographic.org

12. YellowstonePark.com. “Wolf Reintroduction Changes Ecosystem in Yellowstone.” yellowstonepark.com

13. Shikano, I. et al. “Effects of Chemical Insecticide Residues on Aprehend for Bed Bug Management.” Insects 12(3):214 (March 2021). PMC 7998477

14. Purdue University. “Integrated Pest Management Courses.” eventreg.purdue.edu/info/pest

15. NPMA. “Online Learning Center.” npmapestworld.org

16. Entomological Society of America. “Online Programs and Courses.” entsoc.org

ADDITIONAL DISCLAIMER AND SAFETY NOTICE

This module discusses case studies, research findings, and emerging technologies related to nuisance species management. The content is intended to develop critical thinking, introduce students to the biological and ecological foundations of the field, and prepare them for further professional training. It is NOT a substitute for the professional training, licensure, supervised apprenticeships, and hands-on experience required to legally and safely practice pest management, wildlife control, or pesticide application in any U.S. state.

Many of the substances discussed in this module are regulated poisons. Anticoagulant rodenticides, sodium nitrite, warfarin, and various insecticides can cause serious injury or death to humans, pets, livestock, and non-target wildlife when improperly handled. The recent death of multiple mountain lions in Southern California — animals found with six different anticoagulant compounds in their livers, poisoned through the food chain by consuming prey that had eaten rodent bait — is a sobering reminder that these chemicals do not stay where you put them. They move through ecosystems in ways that are often invisible until it is too late.

Several technologies discussed here — including sodium nitrite baits for feral swine, gene drives, entomopathogenic fungi, and wildlife contraceptives — are experimental, partially approved, or subject to ongoing regulatory review. Their inclusion in this module reflects their value as examples of innovative thinking, not an endorsement of their unregulated use.

Before taking any action to manage pests, nuisance wildlife, or invasive species, you must: consult with licensed pest management professionals, follow all applicable federal, state, and local laws and regulations, obtain all required licenses and certifications, use only EPA-registered products according to their labels, wear appropriate personal protective equipment, and consider the impact on non-target species and the broader ecosystem.

Be good stewards. Protect yourselves, your health, your community, the environment, and the animals — including the non-target pets and wildlife that share our world.

A NOTE TO OUR STUDENTS

If you have read this far, you have already demonstrated something that matters far more than any test score: curiosity. You want to understand how the world works. You want to learn. That is the foundation of every great professional career.

The field of nuisance species management is about solving problems that most people do not want to think about, let alone deal with. It requires knowledge, patience, humility, and empathy. The best people in this field have a deep respect for the organisms they manage. They do not enjoy causing harm. They understand that every creature — from a bed bug to a feral hog to a mountain lion — is doing what evolution designed it to do: survive. The problem is not the animal. The problem is the conflict between the animal’s needs and ours. The professional’s job is to resolve that conflict with the least possible harm.

We know something about being underestimated. We know something about being written off. If you are reading this from inside a facility, you already know what it feels like when people look at you and see a problem instead of a person. We do not see a problem. We see potential. We see someone who had the initiative to pick up this module, read through dozens of pages of biology and ecology and history, and think critically about how the natural world works.

The people in this profession — and in every skilled trade — do things that other people cannot or will not do for themselves. They solve problems. They protect communities. They contribute. That is what it means to be a professional. And that is what we are preparing you to become.

We believe in you. We are glad you are here.

— The CM-Tech Team

You didn’t fail school, school failed you.