What Are Aphids & 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 molds 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 Wasps & How Can They Help? Aphidius ervi are natural parasites of Aphids (also known as Greenfly & Blackfly). These tiny beneficial insects will lay their eggs inside the Aphids. The Aphid then dies and turns into a parasitised mummy. This mummy is brown in colour and contains a developing ervi wasp. The wasp will grow and eat its way of the Aphid, puncturing a small hole through the mummified Aphid in order to emerge. This process takes about 2 weeks in a suitable environment. The newly emerged ervi wasp will then start to seek out more Aphids to parasitise 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 Apply Ervi? The ervi are more effective if introduced in a controlled environment such as a greenhouse. When Should I Apply Ervi? The Aphidius ervi should be used in peak Aphid season which is from March to September. How Many Ervi Wasps Do I Need? The ervi are suppled in shaker bottles of either 250, or 500. One bottle of 250 wasps 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 The 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 Natural Pyrethrum or SB Plant Invigorator 2 days prior to use. Other chemical 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.
