Aphid Parasitic Wasp - Aphidius ervi

What are Aphids and how do I identify them?

Aphid is a name for a large group of insects, many of which can cause serious damage to plants. They extract sap from plants causing a reduction in plant growth, reduced yields, and sometimes defoliation. Aphids can also secrete toxic substances into the plants. The Aphids take proteins from the sap and then excrete the excess sugar left in the sap back onto plants. This causes a sticky mess on the leaves, which black moulds often grow on.

Aphids are soft bodied and often shed white skins onto leaves. Adult Aphids can be green, yellow, pink, black, grey or brown.

What are Aphidius ervi predators and how can they help?

Aphidius ervi are natural parasites of Aphids and Greenfly. These tiny beneficial insects lay their eggs inside Aphids. The Aphid then dies and turns into a parasitised mummy. This is brown in colour and contains a developing ervi wasp. The wasp will grow and eat its way out of the Aphid, puncturing a small hole through the mummy in order to emerge. This process takes about 2 weeks in a suitable environment. The newly emerged ervi will then start to search for other Aphids to lay eggs in and kill. This is a classic example of biological control at work. 

The Aphidius ervi are specialist parasitic wasps of the:

  • Glasshouse Potato Aphid (Aulacorthum solani)
  • Potato Aphid (Macrosiphum euphorbiae)
  • Tobacco Aphid (Myzus persicae var nicotianae)

What conditions do the ervi require?

The Aphidius ervi are active in temperatures ranging from 10 - 30.

Where should I use ervi?

The ervi are more effective if introduced in a controlled environment such as a greenhouse.

When should I use ervi?

The Aphidius ervi should be used in peak Aphid season which is from March to September.

How many ervi predators do I need?

The ervi are suppled in shaker bottles of 250. One bottle will treat an average small greenhouse.

Repeat applications may be required for heavy infestations of Aphids, or if treating Aphids over a season. In such cases it is recommended that you introduce the Aphidius ervi every 2 weeks (in a peak Aphid season).

In cases of lighter infestation, it is recommended that the ervi be introduced for at least 3 weeks.

Large Aphid colonies may also require the introduction of Lacewing larvae, Ladybird larvae or the Aphidoletes aphidimyza

If there are multiple species of Aphids present, we recommend the introduction of Aphiscout, a product containing multiple Aphid parasites

How do I apply Aphidius ervi?

Pour the contents of the shaker bottle at the base of plants, on dry material. The wasps will emerge within a few days, fly up from below, and seek out the Aphids. The Ervi can also be applied using our distribution boxes which act as small breeding sites for the wasps, and can be hung onto stems or leaves.

Full instructions will be provided on delivery.

Chemical Pesticides

Aphidius ervi is a living creature and can be affected by any chemical pesticides used within the previous few weeks. As a general guide, refrain from using Pyrethrum or SB Plant Invigorator 2 days prior to use. Other chemicals insecticides can have long lasting residues that could harm ervi and other parasites for much longer periods. Refrain from using these products or check with Dragonfli for information on the effect of these products on our predators.