Scale Insects: Their Control and Prevention

Scale insects involve small creatures ranging from the size of 2 to 3 mm in length. These are the most common pests performing damage in most indoor plants and orchards. It feeds on the plant tissue by sucking it of its sap; thus, weakening the host plant.

Common Species of Scale Insects in Australia
Scale insects are given this name because of their scaly cover protecting itself. Typical examples of which are the Pink Wax Scale, Soft Brown Scale and the Citrus Red Scale.

Pink Wax Scale, Ceroplastes rubens
The adult insect has a hard wax covering with pink to pale red color. It grows as long as 3 to 4 mm long characterized by a globular and smooth shape with two lobes present on each of its side. It is common in the east coast section of Australia and feeds on mangoes, avocadoes, citrus, longan, custard apple, native Australian shrubs like lillypilly, callistemon, umbrella tree, and pittosporum, and exotic ornamental plants like the ixora.

Soft Brown Scale, Coccus hesperidum
This appears as brown, oval, and flattened insects measuring 2-5 mm long. It commonly appears during the summer season and rests on the midribs and veins of leaves like citrus, daphne, oleander, fig, camellia, and palms. It prefers the warm dry climate and can affect trees even up to ten years of age.

Citrus Red Scale, Aonidiella Auranti
Citrus Red Scale has been proven the most damaging. It has a semi-transparent and reddish brown color, which favors feeding on citrus trees resulting to loss in yield for farmers because of the death of citrus trees. It typically settles on the stems, leaves, branches, and fruits of plants and measures only 2mm in diameter.

Life Cycle and Physical Attributes of Scale Insects
These pests are present all year round, which makes it more difficult to fully guard your plants from its infestation. Nevertheless, the egg are most likely to hatch during the spring season and extends its abundance through the summer months.

It has a round to oval flat body and exhibits an orange brown color to a whitish shade covered with powdery coating. These insects remain fixed in a place for the most of the summer months with very little change, except for a slightly convex shape on its body as it mature.

How to Identify Scale Insect Infestation on your Plant
The following are the symptoms you will find in a plant infested with Scale Insects:

The presence of shell-like bumps on the stems of plants and the underside of the leaves

Poor growth on the plants

Deposit of eggs with the appearance of white waxy fibers during the early


Presence of sooty mold on the leaf of the plant

How to Control the Growth and Spread of Scale Insects
The following are methods used by farmers to get rid of these scale insects in their lawn or orchard:

The Cultural Approach
News of scale insect infestation is immediately acted upon by farmers by removing the infected plant material and disposing of it at the soonest time possible. If the plant has been heavily infested then the only option left is to destroy the plant and replace it with another before it starts infecting other trees and plants as well. In any case, rubbing off the leaf with a damp cloth has been seen as an effective method.

The Biological Natural Approach
The Integrated Pest Management of Australia has proposed the use of parasitic of wasps namely the Aphytis lignanensis, Aphytic melinus, and Comperiella spp. At times, the scale eating ladybird is also utilized for it to feast on the scale insects, particularly that of the Citrus Red Scale. All of which can be purchased from supplier of biological control products for gardening.

The Chemical Approach
The last and quickest option is the use of pesticides to easily eliminate these scale insects. 

Organic, Natural Solution to treat Scale Insects