# Beneficial Insects and Biological Pest Control > Beneficial Insects and Biological Pest Control is about using animals instead of chemicals: which predators eat which pests, how the industry that sells insects actually works, why the famous… Canonical: https://wiki.soapbox.community/wiki/Beneficial_Insects_and_Biological_Pest_Control Section: Plants and preparation Last updated: 2026-10-04 Publisher: Library of Ashurbanipal (Van Kush Family Research Institute), https://wiki.soapbox.community **Beneficial Insects and Biological Pest Control** is about using animals instead of chemicals: which predators eat which pests, how the **industry that sells insects** actually works, why the famous ladybird-and-aphid pairing is **mostly sold wrong**, and how the whole thing connects to keeping poultry and — genuinely — to **farming aphids on purpose**. Alpha. ## 1. The three kinds of biological control - **Conservation** — change the farm so the predators that already live there stay and breed: flowering strips, beetle banks, hedgerows, not spraying broad-spectrum insecticides. **Cheapest, most durable, and the one most people skip.** - **Augmentation** — buy and release natural enemies. Either **inoculative** (release a few early and let them build up, the greenhouse model) or **inundative** (release huge numbers as a living pesticide, with no expectation they persist). - **Classical** — import a specialist natural enemy from a pest's homeland against an invasive pest, release once, and it establishes permanently. Spectacular when it works, and the source of the field's worst disasters (§6). ## 2. Who eats what ### Predators - **Ladybirds / ladybugs** (Coccinellidae) — aphids above all, plus scale, mealybugs, mites. A larva eats far more than the adult; **the larva is the workhorse** and looks nothing like the beetle (small, spiky, alligator-shaped, often black and orange). Many people kill them not recognising them. - **Lacewings** (*Chrysoperla*) — the larva is called the **aphid lion** and is a more reliable buy than ladybirds. Adults eat only nectar and pollen. - **Hoverflies** (Syrphidae) — larvae are serious aphid predators; adults are pollinators. **Attracted by flowers, not bought** — pure conservation control. - **Predatory mites** — ***Phytoseiulus persimilis*** is the specialist against two-spotted spider mite and is one of the most effective biological controls in existence. ***Amblyseius*** / ***Neoseiulus*** species handle thrips and broad mites. - ***Orius*** (minute pirate bugs) — thrips, mites, small larvae. - **Rove and ground beetles** — soil-dwelling pests, slugs, root maggots; conserved rather than bought. - **Spiders** — generalists, enormously important, almost never credited. ### Parasitoids — the ones that do the heavy lifting A parasitoid lays an egg in or on a host; the larva eats it from inside and kills it. **This is the category commercial control mostly runs on.** - ***Aphidius*** wasps — lay in aphids, which turn into bronze "**mummies**". Seeing mummies means control is already working. - ***Encarsia formosa*** — against glasshouse whitefly, **used commercially since the 1920s** and the oldest ongoing biological control programme in the world. - ***Trichogramma*** — tiny wasps that parasitise moth and butterfly **eggs**, so the caterpillar never hatches. Sold by the million. - ***Aphelinus***. ***Diglyphus*** — leafminers. ***Dacnusa***. ***Cotesia*** — caterpillars. - **None of these sting people.** Most are a millimetre or two long. ### Pathogens and nematodes - ***Bacillus thuringiensis*** (Bt) — a bacterium whose crystal protein destroys the gut of specific larvae. ***kurstaki*** for caterpillars, ***israelensis*** for mosquito and fungus-gnat larvae. Selective and the backbone of organic caterpillar control. - ***Beauveria bassiana*** and ***Metarhizium*** — fungi that infect insects through the cuticle. Need humidity. - **Entomopathogenic nematodes** — ***Steinernema*** and ***Heterorhabditis***, microscopic worms that enter soil pests and release a lethal bacterium. Excellent for fungus gnats and grubs; must be watered in and kept moist. ## 3. The ladybird problem — why the famous one is usually sold wrong This is the most instructive failure in the whole retail trade. - Most ladybirds sold in North America are ***Hippodamia convergens*** that were **not reared — they were harvested**. They aggregate in huge overwintering masses in the Sierra Nevada and are **vacuumed up by the gallon** from the wild. - Those beetles are physiologically primed to **migrate** when they warm up. Released on a garden, **most simply fly away within a day or two**. - They also arrive carrying whatever the wild population carried, including the parasite ***Dinocampus coccinellae*** and microsporidian infections — so you may be importing disease into your local population. - **What actually helps if you buy them:** refrigerate, release at **dusk**, water the plants first (they will not leave while drinking), and release at the base of infested plants. Even then, expect heavy loss. - **What actually works better:** buy **lacewing larvae** or ***Aphidius*** instead — reared, not harvested, and they cannot fly off as larvae — or do conservation control and let your own hoverflies and ladybirds build up. - **The honest summary:** ladybirds are the product people recognise, which is why they are sold. They are rarely the right purchase. ## 4. The industry - It is a real sector. The **International Biocontrol Manufacturers Association** represents it; the large firms are **Koppert** (Netherlands), **Biobest** (Belgium) and **BioWorks**, alongside many regional insectaries. - **Greenhouses are the economic engine** — enclosed space, high-value crops, and pests that have evolved resistance to everything sprayable. Dutch and Belgian glasshouse tomato and pepper production runs substantially on bought predators. - **How it is sold:** mites and wasps in **bottles with vermiculite carrier**, or in **sachets** that hang on a plant and release a trickle of mites over weeks; ***Encarsia*** as pupae glued to cards; ***Trichogramma*** likewise; nematodes as a wettable powder. - **Banker plants** are the elegant trick: grow a plant with a **harmless** pest on it — cereal plants with **bird-cherry oat aphids**, which will not touch your tomatoes — so that the ***Aphidius*** population has something to breed on continuously. **That is deliberate aphid farming, as infrastructure.** - **Living products have real constraints:** they are perishable, they must arrive fast, they are inspected at borders, and in many countries releasing a non-native species requires a permit. **Check before importing anything.** - **Quality varies.** Reputable suppliers state species, life stage, count and a use-by date. A bag of unspecified "ladybugs" is the low end of the trade. ## 5. Aphids, ants and farming them on purpose - **Ants farm aphids** — genuinely. They protect aphid colonies from predators, carry them to fresh growth, overwinter their eggs, and harvest the **honeydew** the aphids excrete. Some ants chemically suppress the aphids' winged forms to stop the herd dispersing. - **Practical consequence:** if you have ants running up a plant, **your biological control will fail**, because the ants will fight off the ladybirds and wasps. **Deal with the ants first** — a sticky band on the stem is usually enough. This single point explains a great many "the predators didn't work" complaints. - **People farm aphids too**, for two reasons: as **banker-plant hosts** to keep parasitoid wasps breeding (above), and as **live feed** for rearing predators in insectaries and for feeding small reptiles, fish and birds. - **Honeydew** is also the source of **honeydew honey** (fir, pine), which bees make from aphid excretion rather than nectar — a premium product in central Europe. ## 6. Poultry, and the limits of letting animals do it - **Chickens, ducks and guineafowl** are real pest control. **Guineafowl** are the specialists for **ticks** and will patrol a perimeter. **Ducks — Indian Runners especially — are better than chickens in a vegetable garden**, because they take slugs and snails without the destructive scratching chickens do. - The **rice-duck** system of East Asia is the classic integration: ducks in the paddy eat insects and weeds, fertilise as they go, and their paddling muddies the water enough to suppress weed germination. - **Chickens following cattle** break parasite cycles by scratching through dung and eating fly larvae. - **The limits, stated plainly:** birds are **not selective**. They eat your beneficial insects alongside the pests, they eat seedlings and fruit, they scratch out mulch and shallow roots, and their manure is a **food-safety consideration** near ready-to-eat crops — which is why commercial standards impose intervals between grazing poultry and harvest. **Use them before planting and after harvest, or in an orchard, rather than in a bed of seedlings.** ## 7. When classical control goes wrong The field's honest record includes serious failures, and they all share one cause: **a generalist was released.** - **Cane toads** in Australia (1935), imported against cane beetles, which they largely failed to control while becoming a continental ecological disaster. - ***Harmonia axyridis***, the harlequin ladybird, introduced widely for aphid control, is now an invasive pest across Europe and North America that **displaces native ladybirds**, eats fruit, and swarms into houses. - ***Rodolia cardinalis*** against cottony cushion scale in California (1888) is the great success and the founding case of the discipline — a **specialist**, which is exactly the point. - **The rule the field learned:** release **specialists** with host-range testing, never generalists. Modern programmes require extensive pre-release testing for precisely this reason. ## 8. Doing it in practice 1. **Identify the pest correctly.** Everything downstream depends on it; the right predator for a spider mite does nothing for thrips. 1. **Stop spraying broad-spectrum insecticides.** They kill predators faster than pests, and the pest rebounds first — the **pesticide treadmill**. 1. **Deal with ants** if there are any. 1. **Release early, at low pest density.** Biological control **manages** a population; it cannot rescue an infestation. This is the most common mistake. 1. **Match the environment** — nematodes need moisture, fungi need humidity, mites need the right temperature. 1. **Give it weeks, not days**, and look for evidence it is working: **aphid mummies**, larvae present, pest numbers flattening rather than crashing. 1. **Provide flowers.** Adult hoverflies, lacewings and parasitoid wasps feed on nectar and pollen; umbellifers (dill, fennel, coriander) and alyssum are the standard choices. ## 9. Where this connects - Botanical and chemical alternatives, and when they are the right tool: Neem, Botanical Pesticides and What Actually Works. - Feeding the plant rather than the pest: Plant Nutrients and Diagnosing Deficiencies: Reading a Leaf. ## Sources - van Lenteren J. C., "The state of commercial augmentative biological control", *BioControl* 57 (2012) — the industry, species sold, and quality control. - Caltagirone L. E. and Doutt R. L., "The history of the vedalia beetle importation to California", *Annual Review of Entomology* 34 (1989). - Roy H. E. and Wajnberg E. (eds.), *From Biological Control to Invasion: the ladybird Harmonia axyridis* (2008). - Stiling P. and Cornelissen T., meta-analysis of biological control success rates, *Biological Control* 34 (2005). - Way M. J., "Mutualism between ants and honeydew-producing Homoptera", *Annual Review of Entomology* 8 (1963). - Hoy M. A., *Agricultural Acarology* (2011) — *Phytoseiulus* and predatory mite practice. - University extension IPM guides (UC IPM, Cornell) on *Hippodamia convergens* collection, dispersal and release practice.