Biological Control

Biological control (biocontrol) is a pest-management method that uses natural predators, parasites, or pathogens to reduce pest populations instead of relying on chemical pesticides. It's one of the core tools inside integrated pest management (IPM).

Verified for the 2027 AP Environmental Science examLast updated June 2026

What is Biological Control?

Biological control means fighting pests with living organisms instead of chemicals. You introduce or encourage a pest's natural enemy (a predator, a parasite, or a disease-causing pathogen) so it knocks the pest population down for you. Classic example: releasing ladybugs to eat aphids, or bringing in a parasitic wasp to attack a crop pest.

In the AP CED, biocontrol shows up as one of the methods bundled inside integrated pest management (IPM) under EK STB-1.C.1. IPM combines biological, physical, and limited chemical methods so you control pests while minimizing damage to the environment. Biocontrol is the "biological" piece of that combo, sitting alongside crop rotation, intercropping, and other tactics. The whole point is to lean on natural processes first and save chemicals for last.

Why Biological Control matters in AP Environmental Science

Biological control lives mainly in Unit 5: Land and Water Use, specifically topic 5.14, and connects back to Unit 2: The Living World through ecosystem services. It directly supports learning objective AP Enviro 5.14.A (describe IPM) and AP Enviro 5.14.B (the benefits and drawbacks of IPM). Per EK STB-1.D.1, biocontrol and the rest of IPM reduce the risk pesticides pose to wildlife, water supplies, and human health. Per EK STB-1.D.2, those benefits come with a cost: IPM can be complex and expensive to run. On the exam, that benefit-versus-drawback tension is exactly what you're asked to weigh.

How Biological Control connects across the course

Integrated Pest Management (IPM) (Unit 5)

Biocontrol isn't a standalone strategy on the exam, it's one ingredient in the IPM recipe. IPM stacks biological, physical, and limited chemical methods together, so anytime a question mentions natural predators it's really testing whether you can place them inside the larger IPM toolkit.

Predators and Parasites (Unit 2)

Biocontrol is just predation and parasitism put to work for humans. The same ecological relationships you study in community interactions (a wasp parasitizing a beetle, a beetle eating a pest) become a management tool when a farmer deliberately introduces them.

Ecosystem Services (Unit 2)

Natural pest control is a regulating ecosystem service nature already provides for free. Biocontrol works by amplifying that service, which links topic 5.14 straight back to topic 2.2 and the idea that disrupting ecosystems (AP Enviro 2.2.B) can wreck the free pest control you depend on.

Is Biological Control on the AP Environmental Science exam?

Expect biological control in multiple-choice stems framed around IPM scenarios: a citrus orchard with scale insects, a city fighting mosquitoes, or a farmer choosing among strategies. Questions often ask you to pick the most sustainable combination of IPM methods or to identify why one approach minimizes environmental disruption. Watch for the twist where a pest develops resistance to a biological control agent, and you have to choose how to keep IPM effective. On FRQs, biocontrol shows up inside sustainable agriculture and land-use prompts (like the 2023 SAQ on sustainable crop varieties), where you may need to propose a method that reduces pesticide use or explain a benefit and a drawback. The move you'll make most: name biocontrol, then justify it against chemical pesticides on cost, health, and environmental risk.

Biological Control vs Integrated Pest Management (IPM)

Biological control is one method; IPM is the whole strategy that contains it. IPM mixes biological, physical, and limited chemical approaches together. If a question describes using only natural predators, that's biocontrol. If it describes combining several methods to control pests while protecting the environment, that's IPM.

Key things to remember about Biological Control

  • Biological control uses living organisms (predators, parasites, or pathogens) to reduce pest populations instead of chemical pesticides.

  • It's one component of integrated pest management (IPM), not a substitute for it, per EK STB-1.C.1.

  • The main benefit is lower risk to wildlife, water supplies, and human health (EK STB-1.D.1).

  • The main drawback is that IPM, including biocontrol, can be complex and expensive to implement (EK STB-1.D.2).

  • Natural pest control is a regulating ecosystem service, which links topic 5.14 back to ecosystem services in topic 2.2.

  • On the exam, you'll often weigh biocontrol against chemical pesticides or place it inside a multi-method IPM plan.

Frequently asked questions about Biological Control

What is biological control in AP Environmental Science?

It's a pest-management method that uses natural predators, parasites, or pathogens to reduce pest populations without chemical pesticides. In the CED it's one of the biological methods bundled inside integrated pest management (IPM) under topic 5.14.

Is biological control the same as integrated pest management?

No. Biological control is just one tool; IPM is the broader strategy that combines biological, physical, and limited chemical methods. Think of biocontrol as one ingredient inside the IPM recipe.

Why use biological control instead of pesticides?

Biocontrol reduces the risk pesticides pose to wildlife, water supplies, and human health (EK STB-1.D.1). The tradeoff is that it can be more complex and expensive to set up than spraying chemicals (EK STB-1.D.2).

What's a real example of biological control for the AP exam?

Releasing ladybugs to eat aphids or introducing a parasitic wasp to attack a crop pest. The same idea applies to a citrus orchard fighting scale insects or a city using natural mosquito predators in an IPM plan.

How does biological control connect to ecosystem services?

Natural pest control is a regulating ecosystem service nature provides for free, which ties topic 5.14 to topic 2.2. Disrupting ecosystems can damage that free pest control, which is exactly the kind of consequence AP Enviro 2.2.B asks you to describe.