Scale insects are Leaf-sucking insects that look like tiny oval limpets. They cling to leaves, stems or branches of trees and shrubs. There are several types of scale, some attacking a wide range of plants but others only attacking specific ones.
For most of their lives the adult females stay in one place, protected by the waxy brown ‘shell’. Their feeding on the sap causes yellowing of the leaves, weakening the plant. They lay their eggs under the scales. The newly hatched scale insects crawl all over the plants, so that unless dealt with the infestation spreads.
The pests can be controlled by spraying with bifenthrin when the young scale insects are hatching. Adult scales can be scraped off with the fingernails or, better, wiped off with methylated spirit which also destroys any eggs that may remain.