Types of Biological Pest Control and 4 Other Alternatives

There are three main types of biological pest control: classical (bringing in a natural enemy from the pest’s home range), augmentative (buying and releasing natural enemies) and conservation (protecting the natural enemies already on the farm), as the UC Statewide IPM Program’s guide to natural enemies sets out. Many guides add a fourth group, biopesticides made from microbes, plants or minerals. Biological control is one of five alternative pest control methods; the others are cultural, physical, botanical and genetic.

This guide explains each method in plain terms, with dated numbers from US government agencies and peer-reviewed work. It shows how often classical releases succeed, how far insect-resistant corn has spread and how sterile flies are being used against New World screwworm. A calculator lets you test whether a lower-spray program pays on your own acres.

Types of biological pest control at a glance

Biological control is the use of living things, called natural enemies, to keep pests below the level that causes economic damage. The UC IPM guide groups natural enemies into predators, parasites (often called parasitoids) and pathogens. Most parasites and pathogens, and many predators, attack only a small range of closely related pests. That narrow target range means they usually do little harm to pollinators and other beneficial insects.

1. Classical biological control

Classical control targets pests that arrived from another continent without their natural enemies. Scientists search the pest’s native range, test candidate enemies for safety to native species, and then release them. If the enemy establishes, it can spread on its own and keep working for decades at no cost to the grower.

The record is mixed, and it helps to know the odds. The BIOCAT database, updated by Cock and colleagues in BioControl (2016), counted 6,158 introductions of 2,384 different insect natural enemies against 588 insect pest species in 148 countries up to the end of 2010. Of those introductions, 2,007 (32.6%) led to establishment and 620 (10.1%) gave satisfactory control. The same review found fewer introductions each decade since the 1970s, but a higher share of them now establish and succeed. Better safety testing and better matching of enemy to pest explain part of that change.

Farmers do not run classical programs themselves. In the US they are run by USDA, state agencies and universities, and any release of a new organism needs a permit. What a grower can do is report new pests early and avoid spraying where a released enemy is building up.

2. Augmentative biological control

Augmentation means buying natural enemies from an insectary and releasing them. Inoculative releases put out a small number early in the season so they breed and keep pests down later. Inundative releases flood the crop with large numbers for a quick effect, much like a spray that does not breed.

The UC IPM guide lists the main groups sold for release: predatory mites against spider mites, lady beetles and lacewings against aphids, parasitic wasps such as Trichogramma against moth eggs, and beneficial nematodes against soil insects. Results depend on timing. Releases work best when pest numbers are still low, when the right species is matched to the pest, and when broad-spectrum sprays are avoided before and after release.

Greenhouses suit augmentation best, because the enemies cannot fly away and the climate is controlled. In open fields, releases often need repeating, so the cost per acre is higher. Ask the supplier for release rates per square foot or per acre for your crop, and check shipping times, because live insects lose quality in transit.

3. Conservation biological control

Conservation control costs the least and suits every farm. It means farming in a way that keeps the natural enemies already in and around your fields alive. The UC IPM guide puts protecting natural enemies first among its tips, ahead of buying any.

• Choose selective pesticides, and spot-treat instead of spraying whole fields.
• Plant flowering strips or hedgerows that give adult parasitic wasps and hoverflies nectar and pollen.
• Leave some uncut strips at harvest so predators have somewhere to go.
• Control ants that protect aphids and scale insects from their enemies.
• Reduce dust on leaves along farm roads, which can favour spider mites.

4. Biopesticides

The US Environmental Protection Agency describes biopesticides as pesticides made from natural materials such as animals, plants, bacteria and certain minerals. As of August 31, 2020, EPA’s page on what biopesticides are counted 390 registered biopesticide active ingredients. They come in three classes: microbial pesticides, plant-incorporated protectants (such as Bt traits in crops) and biochemical pesticides (such as insect pheromones). EPA notes that new biopesticides are often registered in less than a year, against an average of more than three years for conventional pesticides.

The best-known microbial product is Bacillus thuringiensis. The National Pesticide Information Center’s Bt fact sheet explains that Bt proteins harm insects only when they eat them, and that different strains target caterpillars, beetle larvae or mosquito and fly larvae. Pick the strain that matches your pest. Biopesticides are still pesticides: read and follow the label, and check local rules before use.

The video below shows one of these types in action: a predatory mite released against spider mites.

▶ How the predatory mite Phytoseiulus persimilis is used to control spider mites, an example of augmentative biological control. · 13:25

How well biological control works

Biological control rarely gives the instant, near-total kill growers expect from a broad-spectrum spray. It works by keeping pests below a damage level over time. That changes what success looks like: a few pests in the field are normal and even useful, because they feed the natural enemies.

The BIOCAT figures above give the clearest long-run view for classical releases. Out of every 100 introductions, about 33 established and about 10 gave satisfactory control. Each success, however, can protect a crop across a whole region without further cost, which is why agencies keep making releases.

For augmentative and conservation methods, results vary by crop, pest and climate. University extension services publish release rates and thresholds by crop; start there before you buy.

Chart

Outcomes of classical biological control releases

Introductions of insect natural enemies against insect pests worldwide, to the end of 2010

Cultural pest control: change the field, not the spray

Cultural control means using normal farm practices to make the field a poor place for pests. The US EPA’s IPM principles page lists it alongside mechanical control as one of the lower-risk options to try before targeted spraying. Common cultural tools are:

• Crop rotation. Moving crops breaks the cycle of pests that stay in one field, such as corn rootworm or soil nematodes.
• Planting date. Planting earlier or later can avoid the peak flight of a key pest.
• Sanitation. Removing crop residue, culls and volunteer plants takes away places for pests to overwinter.
• Trap crops. A strip of a crop the pest prefers draws it away from the main crop, where it can be destroyed or sprayed in a small area.
• Balanced fertility and watering. Too much nitrogen gives soft growth that aphids and mites like; water stress makes some crops more open to attack.
• Clean seed and transplants. Many diseases and pests arrive on planting stock.

Cultural control costs little but needs planning a season or more ahead. It also works best across a whole area, so talk to neighbours about shared pests and timing.

Physical and mechanical pest control

Physical methods block, trap or remove pests directly. They include row covers and insect netting, sticky traps, mulches that confuse aphids, hand-picking, vacuums in strawberries, tillage that exposes soil pests, and flaming for weeds. In stored grain, cooling and drying bins slows insect growth; controlled atmospheres with low oxygen are an alternative to fumigation in some stores.

Pheromone tools sit between physical and biological control. Mating disruption fills an orchard with a synthetic copy of the female moth’s scent so males cannot find mates. In Washington apples, WSU reported that mating disruption for codling moth covered close to 40,000 of about 160,000 bearing apple acres in 1998, roughly 20 to 25%, in a WSU news report from that year. By 2010, Washington State Magazine quoted WSU entomologist Jay Brunner saying better than 80% of the state’s apple acres were treated. It does not give 100% control, but it sharply cut the number of insecticide sprays needed. A USDA Agricultural Research Service report (1997) said some growers in the areawide codling moth program cut insecticide use by 70%.

Pheromone traps also serve as monitoring tools. Trap counts tell you when a pest flight starts, so any spray goes on at the right time instead of by calendar.

Botanical and plant-based pest control

Botanical insecticides come from plants. The common ones are neem oil (and its main active part, azadirachtin), pyrethrins from chrysanthemum flowers, plant essential oils, and horticultural oils made from plant or mineral oil. Insecticidal soaps are a related group.

The NPIC neem oil fact sheet says azadirachtin reduces insect feeding, repels pests and disrupts insect hormones, which makes it harder for them to grow and lay eggs. It breaks down fast: its half-life in soil ranges from 3 to 44 days and in water from 48 minutes to 4 days. NPIC rates neem oil as practically non-toxic to birds, mammals and bees, but azadirachtin is moderately toxic to fish, so keep it away from water.

Plant-based does not mean harmless. Pyrethrins kill bees on contact if they are sprayed on open flowers, and oils can burn leaves in heat. Fast breakdown also means more frequent use. Treat botanicals as one tool in a plan, read and follow the label, and check which products are allowed under your organic or local rules.

▶ Organic ways to manage chilli thrips (Scirtothrips dorsalis), including plant-based sprays and monitoring. · 13:24

Genetic and biotechnology pest control

Genetic methods change the crop or the pest. On the crop side, plant breeders have long selected varieties that resist pests and diseases. Genetic engineering added Bt traits, which let the plant make the same insect-specific proteins as the Bt spray.

Chart

Bt (insect-resistant) corn share of US corn acres

Percent of planted corn acres with Bt traits, selected years

The USDA Economic Research Service reports that Bt corn rose from about 8% of US corn acres in 1997 to 19% in 2000 and 87% in 2025. Bt cotton went from 15% of US cotton acres in 1997 to 37% in 2001. Bt traits now target the European corn borer, the corn rootworm and the corn earworm.

On the pest side, the sterile insect technique (SIT) releases huge numbers of male insects that were sterilised with radiation. When they mate with wild females, no offspring are born, and the wild population falls. SIT is now the main tool against New World screwworm, a fly whose larvae eat living flesh of cattle and other animals.

The USDA APHIS sterile fly page (updated August 2026) says the COPEG plant in Panama produces about 100 million sterile flies per week. A converted plant in Metapa, Mexico was completed in late June 2026 and is ramping up to 100 million per week. A production plant under construction in southern Texas has a projected capacity of 300 million per week, and a dispersal centre at Moore Air Base in Edinburg, Texas can release up to 100 million per week.

Chart

Sterile screwworm fly capacity by facility

Million sterile flies per week; the Texas production plant is under construction

Integrated pest management: putting the methods together

No single alternative replaces every spray. Integrated pest management (IPM) combines them. The FAO definition of IPM describes it as careful use of all available pest control techniques, combining biological, chemical, physical and crop-specific (cultural) measures to grow healthy crops and keep pesticide use and risk low. EPA’s IPM page sets out the same order: set action thresholds, monitor and identify pests, prevent, then control with the lowest-risk tools first, and use targeted sprays only if those fail.

IPM also slows pesticide resistance. EPA’s page on slowing pest resistance notes that many pesticides have lost effectiveness as pests became resistant, and lists steps such as rotating crops so the same products are not used season after season. Rotating modes of action, using non-chemical tools and keeping refuges all reduce the pressure that selects for resistant pests.

How to build an alternative pest control plan: 6 steps

1. Identify the pest. Confirm the species, its life stage and whether natural enemies are already present. A hand lens and your extension office help here.
2. Set a threshold. Decide how many pests or how much damage is acceptable before you act. Extension guides publish thresholds for many crops.
3. Monitor on a schedule. Scout fields weekly in season, check traps and note hot spots. Satellite crop maps can show which parts of a large field are under stress so you scout those first.
4. Prevent with cultural and physical tools. Rotation, clean planting stock, sanitation, netting and trap crops.
5. Use biological tools. Protect existing natural enemies, release bought ones where it pays, and use biopesticides when a quick cut is needed.
6. Spray only as a targeted last step. If you must use a synthetic insecticide, choose a selective one, rotate mode of action, follow the label and treat only the affected area.

Pesticide, biopesticide and release decisions depend on crop, region and law. Read and follow the label, check local rules, and get professional advice from an extension agent or certified crop adviser before changing your program.

▶ The shift from routine spraying to integrated pest management, and how remote sensing supports scouting. · 14:45

Is it worth it? Costs of a lower-spray program

Switching methods changes costs in three places: what you spend on control products, what you spend on labour and scouting, and how much crop you lose. A lower-spray program often costs more in materials (dispensers, released insects) and time, and saves on spray passes. Whether it pays depends on your crop value and how damage changes. Use the calculator below with your own numbers. The defaults are examples only and are set close to break-even.

Try the numbers for your own farm below.

Using satellite monitoring to target pest scouting

Satellites cannot see an aphid. What they can show is where plant cover or vigour drops in part of a field compared with the rest, which can point to pest, disease, water or nutrient problems. Scouts can then walk the weak zones first and confirm the cause on the ground. Farmonaut Satellite + AI Farm Monitoring System gives vegetation index maps for fields you draw once, through the season on web, Android and iOS.

FAQ

What are the types of biological pest control?

The three main types are classical (importing a natural enemy of an invasive pest), augmentative (buying and releasing natural enemies) and conservation (protecting natural enemies already present). Biopesticides made from microbes, plants or minerals are often counted as a fourth group.

What is the most common example of biological pest control?

Familiar examples include lady beetles eating aphids, predatory mites released against spider mites in greenhouses, parasitic wasps attacking moth eggs, and sprays of Bacillus thuringiensis against caterpillars.

Are alternative pest control methods as effective as chemical pesticides?

They work more slowly and rarely kill every pest, but used together in IPM they can keep pests below damage levels and reduce sprays. In Washington apples, mating disruption grew to cover better than 80% of apple acres by 2010 and cut the number of insecticide sprays needed.

Is there an alternative to fumigation?

For stored grain, options include cooling and drying grain, sealed storage with low-oxygen or high-carbon-dioxide atmospheres, and good bin hygiene. In soil, crop rotation, resistant varieties and grafted transplants can reduce the need for fumigants. Check local rules and get professional advice for your situation.

Are botanical pesticides safe for bees?

It depends on the product. NPIC rates neem oil as practically non-toxic to bees, while pyrethrins can kill bees on contact. Do not spray open flowers, and follow the label.

Can I use biological control with chemical sprays?

Yes, if you choose selective products, time sprays away from releases, and treat only where needed. Broad-spectrum sprays kill natural enemies and can cause pest outbreaks later.

Related pages on our site: natural pest control methods in farming; eco-friendly pest control on farms; do-it-yourself pest control tips; product traceability; carbon footprinting; crop loans and insurance; fleet management; farm administration; weather API documentation.