3.3.13 - Ornamental and House Plants

The Coccidae or soft scales are notorious pests of ornamental plants, particularly on perennials. The most economically important pest species of Coccidae are usually cosmopolitan in distribution and polyphagous in the choice of host plant. 33 species (with six exceptions) have been selected from several hundred species known from ornamentals, because they are mainly polyphagous and have been reported as pests from at least two continents. Coccidae produce sugar-rich honeydew that provides a medium for the growth of sooty mould. This mould covers the leaves with a black coating of mycelia that interferes with photosynthesis, causing the plants to decline in vigor and to lose their aesthetic value.