Bio-solution · E12 · Ecology & monitoring
Cassava mealybug classical biological control with Anagyrus lopezi instead of insecticides
Replaces
Insecticide spraying (rarely affordable for smallholders) and uncontrolled crop losses from the invasive cassava mealybug in Africa
Insecticide spraying (rarely affordable for smallholders) and uncontrolled crop losses from the invasive cassava mealybug in Africa
→
Scope
Classical biological control — introduction of the South American parasitoid wasp Anagyrus (Epidinocarsis) lopezi across sub-Saharan Africa (IITA-led Africa-wide Biological Control Programme, from 1981)
Classical biological control — introduction of the South American parasitoid wasp Anagyrus (Epidinocarsis) lopezi across sub-Saharan Africa (IITA-led Africa-wide Biological Control Programme, from 1981)
Suppliers 4
| IITA | Nigeria | active |
| Insectec (Pty) Ltd | South Africa | active |
| BioBee | Israel | active |
| BIOMIP BIOLOGICAL QUALITY SL | Spain | active |
Route into Russia / EAEU CLASSIC
- Regulator
- Rosselkhoznadzor / research institutes
- Typical time
- research-led, years
- Legal basis
- Introduction of exotic biocontrol agents needs a quarantine risk assessment; no commercial product route (verify)
Information, not legal advice — confirm the procedure for your product.
Proof 6 claims
Old process
Chemical insecticide application (though rarely used in practice due to cost and availability).
Chemical insecticide application (though rarely used in practice due to cost and availability).
→
New practice
Classical biological control using the parasitoid Anagyrus lopezi.
Classical biological control using the parasitoid Anagyrus lopezi.
- Displaced at scale?
- yes
- Caveats
- The evidence does not show a displacement of a pre-existing chemical insecticide process, as insecticides were rarely used or available for smallholder cassava farmers in sub-Saharan Africa due to high costs and lack of infrastructure. The biological control program replaced the lack of effective control rather than an active chemical industry.
- Hand review
- D2 Africa: Anagyrus lopezi brought cassava mealybug under control in 95% of fields within a decade (CGIAR); insecticides were rarely used before, so it displaced losses more than spraying.
- checked
- 2026-10-06
| The biological control agent Anagyrus lopezi successfully brought the cassava mealybug pest under control in 95% of all fields. “decade, the biological control agent had spread to all the major mealybug infestations and had brought the pest under control in 95% of all the fields (Herren and Neuenschwander, 1991).” sub-Saharan Africa · 1991 · large measured reduction of the old process | government or intergovernmental ✓ iaes.cgiar.org |
| The presence of A. lopezi resulted in an increase in cassava yield by 2.5 t/ha. “The presence of A. lopezi was thus translated into an increase in yield by 2.5 t/ha and this value was subsequently used by Norgaard (1988) to estimate the economic impact of this classical biological control.” Ghana and Côte d’Ivoire · 1988 · | government or intergovernmental ✓ iaes.cgiar.org |
| The benefit-cost ratios for the biological control of the cassava mealybug range from 94:1 to 800:1. “In summary, the benefit-cost ratios of the biological control of cassava mealybug range from 94:1 (under very pessimistic assumptions) to 800:1 (under optimistic assumptions), showing the substantial net benefits of the biological control program.” · 2000-2001 · | government or intergovernmental ✓ iaes.cgiar.org |
| The switch to biological control was driven by the fact that insecticides were rarely used, often unavailable, too expensive for smallholders, and associated with health and environmental concerns. “In reality, insecticides are rarely used because the chemicals and the equipment to spray insect pests are often not available or are too expensive for the smallholder to use, especially on crops such as cassava that are of low cash value (Neuenschwander 1993, 2004). Moreover, in view of the biodiversity losses and …” · 1993-2004 · | government or intergovernmental iaes.cgiar.org |
| The biological control agent Anagyrus lopezi was released in about 150 sites in 20 countries and established in 26 African countries. “From 1981 onward, A. lopezi was released in about 150 sites in 20 countries. ... During the Africa-wide Biological Control project, the neotropical parasitoid Epidinocarsis lopezi (De Santis) (Hymenoptera: Encyrtidae) was established in 26 African countries, causing a satisfactory reduction in the population density of …” Africa · 1981-2000 · large measured reduction of the old process | government or intergovernmental ✓ iaes.cgiar.org |
| The biological control program resulted in a benefit-cost ratio of about 200 to 740. “A reasonable calculation considering compounded interest resulted in a benefit cost ratio of about 200 when cassava was costed at world market prices, and of about 370–740 when inter-African prices were considered.” Africa · 1974-2013 · not applicable | government or intergovernmental ✓ iaes.cgiar.org |
Details
Replaces: insecticides and unchecked losses · Scope: cassava in sub-Saharan Africa · Evidence: high (control), moderate (as a chemical displacement)
The chemical problem#
- The cassava mealybug (Phenacoccus manihoti) arrived in Africa from South America around 1973 and spread across the cassava belt, causing yield losses of up to 80 %.
- Insecticides were the only conventional answer, but they were expensive, rarely available to smallholders and impractical over millions of hectares — so in practice most farmers had no control.
Product overview#
Classical biological control: the parasitoid wasp Anagyrus lopezi, found in the pest’s native range in South America, was mass-reared and released from 1981 by IITA and partners, including from aircraft. It established in 26 African countries and spread on its own, without any farmer having to buy or apply anything.
Active ingredient / Composition#
- The parasitoid Anagyrus (syn. Epidinocarsis) lopezi, released once per site; it reproduces and spreads naturally.
- No product to apply repeatedly; no residues.
Key facts#
| Parameter | Value |
|---|---|
| Control achieved | Pest under control in 95 % of fields within about a decade (Herren & Neuenschwander 1991, via CGIAR) |
| Spread | Released at ~150 sites in 20 countries; established in 26 countries |
| Yield effect | +2.5 t/ha cassava where the parasitoid was present (CGIAR impact study) |
| Benefit-cost ratio | ~200 at world-market prices, 370–740 at inter-African prices; 94:1 to 800:1 across studies (CGIAR) |
| Caveat | Insecticides were rarely used before — the main displacement is of losses, not of spraying |
Advantages#
- Self-sustaining: after establishment the wasp needs no purchases, labour or inputs.
- Reached smallholders who could never have afforded insecticides.
- No residues, no resistance management, no harm to other natural enemies.
Mode of action#
Female A. lopezi lay eggs inside mealybugs; the larva consumes the host from within, and adult females also kill mealybugs by host-feeding. The wasp tracks mealybug populations across the landscape.
Application#
| User | Target | Method, timing and specifics |
|---|---|---|
| National plant-protection services | Invasive mealybug | Import and release the specific parasitoid under quarantine rules; monitor establishment |
| Research institutes (IITA, CABI) | New invasions | Foreign exploration in the pest’s native range, host-specificity testing |
| Commercial insectaries | Greenhouse/orchard mealybugs | Augmentative releases of Anagyrus species (different market from the cassava programme) |
Limitations#
- Classical biocontrol is a public good, not a product: no company sells it; it needs public research funding.
- Each invasion needs its own natural enemy and years of safety testing.
- Control can weaken locally (drought, ants protecting mealybugs, insecticide drift).
Evidence of displacement — D2: measurable displacement (minority share)#
Assessment (hand-reviewed): Africa: Anagyrus lopezi brought cassava mealybug under control in 95% of fields within a decade (CGIAR); insecticides were rarely used before, so it displaced losses more than spraying.
Figures found (verified as quoted, but the assessment above explains why they do not count as displacement evidence for this substitution):
- displacement — The biological control agent Anagyrus lopezi successfully brought the cassava mealybug pest under control in 95% of all fields. (sub-Saharan Africa, 1991; government or intergovernmental: iaes.cgiar.org)
- performance — The presence of A. lopezi resulted in an increase in cassava yield by 2.5 t/ha. (Ghana and Côte d’Ivoire, 1988; government or intergovernmental: iaes.cgiar.org)
- performance — The biological control agent Anagyrus lopezi was released in about 150 sites in 20 countries and established in 26 African countries. (Africa, 1981-2000; government or intergovernmental: iaes.cgiar.org)
- economics — The benefit-cost ratios for the biological control of the cassava mealybug range from 94:1 to 800:1. (—, 2000-2001; government or intergovernmental: iaes.cgiar.org)
Suppliers — real products and services (from the vendor index)#
Companies below are active vendors in the vendor index whose own card (profile / official website) shows this product or service — matched 2026-10-06 by keyword and checked by hand against the card text. Being listed is not an endorsement; open each card for evidence, contacts and status. Commercial Anagyrus products target mealybugs of greenhouse, citrus and vine crops, not cassava.
| Company | Region · Country | What the index shows | Card |
|---|---|---|---|
| IITA | Africa/ME · Nigeria | biological control programmes incl. cassava mealybug control (research institute, not a seller) | card |
| Insectec (Pty) Ltd | Africa/ME · South Africa | natural enemies incl. ANA-TEC and other agents mainly for mealybug | card |
| BioBee | Africa/ME · Israel | BioAnagyrus and other biocontrol agents | card |
| BIOMIP BIOLOGICAL QUALITY SL | Europe · Spain | ANAGYRUS BIOMIP P and other biocontrol agents | card |
Government funding signals#
Scanned 2026-10-06.
China, Brazil, India — national research grants acknowledged in publications#
Papers since 2015 whose title matches “cassava mealybug” and that acknowledge national government funders (Crossref funder metadata; conservative lower bounds). Signal bands used here: Strong ≥30 · Moderate 5–29 · Weak 1–4 · None 0.
| Country | Papers funded (2015–2026) | Signal | Example funded paper |
|---|---|---|---|
| China | 0 | None | – |
| Brazil | 0 | None | – |
| India | 0 | None | – |
Scientific evidence#
- Herren HR, Neuenschwander P (1991). Biological control of cassava pests in Africa. Annual Review of Entomology 36: 257–283.
- Neuenschwander P (2001). Biological control of the cassava mealybug in Africa: a review. Biological Control 21: 214–229.
- Zeddies J, Schaab RP, Neuenschwander P, Herren HR (2001). Economics of biological control of cassava mealybug in Africa. Agricultural Economics 24: 209–219.
- Note: journal references are checked against Crossref.
Bioeconomy value#
One introduced wasp controlled a continental pest on a staple crop, with returns of hundreds of dollars per dollar spent — and it reached farmers that chemical control never could.
Twelfth article of ecology (added 2026-10-06, evidence-first: grade D2 — strong control evidence, but the old practice it displaced was mainly losses, not routine spraying).