Aphids are among the most persistent pests in greenhouse production, capable of rapidly building large populations. Chemical options are available, but they can disrupt beneficial insect programs and often drive resistance in pest populations. This is where Aphidius spp., tiny parasitic wasps, play a vital role in integrated pest management (IPM). Highly efficient at locating and parasitizing aphids, even small, hidden colonies on leaf undersides. Aphidius wasps suppress infestations early, preventing outbreaks without the need for chemicals.
How Aphidius Wasps Control Aphids
A female Aphidius locates aphid hot spots by the smell of honeydew and herbivore-induced plant volatiles. Once it finds a suitable aphid host, it inserts a single egg inside the aphids body. The egg hatches and develops into a larva, the larva slowly feeds on the aphid, keeping it alive until its ready to pupate. During pupation the aphid hardens into a swollen, golden-brown shell known as a “mummy.” A few days later, a new adult wasp emerges from the mummy, ready to parasitize more aphids. This cycle continues, creating a self-sustaining population of natural enemies that increases and decreases with the aphid population.
For growers and IPM specialists, this is a major advantage. Unlike chemical sprays that may require multiple applications, Aphidius spp. expand naturally as long as hosts are present. They provide ongoing suppression, reduce the risk of pest resurgence, and protect other beneficial insects like ladybugs, lacewings, and predatory bugs that are also part of IPM programs.
Lifecycle of Aphidius sp.
Egg Stage: The female wasp deposits a single egg inside an aphid. Once hatched, the larva begins feeding on the aphid’s internal tissues.
Larval Stage: As the larva grows, it kills the host and transforms it into a swollen “mummy.” This stage typically lasts 4–10 days, depending on the temperature.
Pupal Stage: Inside the mummy, the wasp pupates and completes its development. A new adult emerges in about 4–5 days.
Adult Stage: Adult wasps live for roughly one week, during which a single female can parasitize more than 400 aphids, creating a rapid impact on pest populations.
Key Aphidius Species Used in Greenhouses
AphidLiv Aphidius colemani – Widely used against green peach aphid (Myzus persicae), melon or cotton aphid (Aphis gossypii), and other small aphid species.
Aphidius ervi – Best suited for controlling larger aphids such as potato aphid (Macrosiphum euphorbiae) and foxglove aphid (Aulacorthum solani).
Aphidius matricariae – Effective against several common greenhouse aphid species, especially myzus sp.
Best practices when using Aphidius wasps
Start early – Introduce Aphidius preventively when crops are young or as soon as the first aphids are detected.
Support with banker plants – Banker systems, such as the Aphid Banker Plant, use non-crop, non-harmful aphid species to sustain Aphidius wasps. This provides a continuous food source and ensures parasitoids remain active even when pest aphid pressure is low.
Distribute evenly – Place wasps across the greenhouse, focusing on hotspots like new growth where aphids often establish.
Use multiple small releases – Several smaller introductions over time are more effective than a single large release, ensuring a steady population of parasitoids.
Increase rates for outbreaks – In curative situations, higher release numbers may be necessary. Pairing Aphidius with predators like lady beetles or lacewings can improve knockdown.
Check compatibility – Avoid pesticide residues that can harm parasitoids or reduce their effectiveness.
Integrate into IPM – Preventive releases of AphidLiv (Aphidius colemani) help maintain control long term and reduce reliance on chemical sprays.