Chapter 3.1 – Pest Status of Soft Scale Insects: 3.1.1 Economic Importance

As all soft scales ( Coccidae ) are plant-feeding insects, most are potential pests of plants valuable to man. Species of Coccidae imbibe large quantities of plants sap, resulting in a loss of plant vigour, poor growth, die back of twigs and branches, early leaf drop and even, sometimes, death of the entire plant. While penetrating the plant with their piercing stylet-like mouthparts, they also inject saliva that appears to be toxic to the plant and often produces chlorotic, yellow, or red discolouration on the leaves and fruit and/or deformation of the shoots, twigs, and branches. They also cause indirect damage to the plants by excreting (or more correctly eliminating) honeydew, a growth medium for sooty moulds, which produce a black coating over the leaf surface. This coating interferes with photosynthesis and may cause poor growth, a reduction in fruit size and generally give an unsightly appearance to the crop.