Sooty moulds

Are caused by a number of different fungi producing a dark brown or black felt like growth and spores over the surfaces of plants. They usually grow on sugar-rich honeydew, the waste produced by sap-sucking insects as a result of their feeding activities.

A layer of black or dark brown, superficial fungal growth on the stems, buds, flowers and upper leaf surfaces of plants. In the early stages this can take on the appearance of a fine soot-like deposit, and if not treated a thick sheet of growth on plant surfaces. This mould growth is closely associated with sap-sucking pests such as; aphids, mealy bugs, scale insects and whiteflies often found feeding on the plant, above the sooty mould. This mould does not invade the plant tissue but it can cause harm by preventing the affected leaves from functioning properly.