Damage symptoms
Large colonies of mottled arum aphids can greatly reduce plant vigour and kill the plant through sucking of plant sap. However, also at lower densities the aphids can damage plants because they produce large amounts of honeydew, which provides an excellent substrate for the growth of black sooty mould. Large areas of mould covering the leaves can reduce photosynthesis and also result in an unattractive plant with a much lower market value. Neomyzus circumflexus can also transmit plant viruses.