Soft Scale Insect Pest Solution: Metaphycus

Metaphycus Description

Metaphycus (Pronounced: METTA-FY-CUSS) helvolus is a small parasitic wasp about 2mm in length. The female is yellow in colour and parasitises the young stages of soft scale when they have settled on the plant. It is quite active, walking quickly over the leaf surface. Metaphycus is pictured parasitising a scale.

Parasite Life Cycle

The adult female lays up to 6 eggs a day into soft scales. Before laying an egg, she tests the scale with her ovipositor (egg laying tube).  In so doing she kills up to four times as many scales.

The larva develops inside the scale and eventually kills it. These parasitised scales appear darker and flatter than normal. The parasite pupates inside the scale body and the adult emerges by cutting a circular hole in the dead scale. Adults can live for up to 2 months if enough food is available. From egg to adult takes about 11 days at 30°C and 30 days at 20°C.

Metaphycus Usage

  • Metaphycus is only suitable for use in a greenhouse or conservatory.
  • Metaphycus requires a minimum temperature of 22°C (72°F) for at least a few hours each day. This limits use to late spring and summer or hot greenhouses and conservatories.
  • Metaphycus requires good levels of light.
  • Metaphycus cannot be stored and needs to be used immediately upon receipt.
  • Like all Defenders biological controls, Metaphycus is harmless to children, pets and wildlife.

Biological Soft Scale Insect Control Product Details

Defenders supply Metaphycus as adult wasps, occasionally with another species of wasp. The wasps are fragile and cannot survive long away from moisture and food, so should be released in the greenhouse as soon as possible.

Product Name

Area Treated


Soft Scale Parasitoid Mix 25

Contains 25 adult wasps, usually enough for a conservatory or greenhouse up to 150 ft² in area.

Currently Unavailable


All packs are sent with full release instructions contained in the document wallet on the package.

NB. Metaphycus will only be available from late spring to early autumn, it can sometimes be difficult to supply and may become temporarily unavailable. We therefore strongly advise that customers check availability before placing an order for Metaphycus.

Remember! Biological controls are living creatures and can be effected by chemical usage. If you've used any pesticides recently check with us before ordering Metaphycus.