These grubs are not Caterpillars, but are insects in the family Pseudococcidae. They are often mainly white due to an outer layer of wax which controls their water loss, although different species have other colours.

(Photo: courtesy of Sharon Adnum, Bowral)

They all feed by sucking sap from the host plant through a tubular mouth that is poked into the plant. Many species are fussy, and only attack particular plants.

(Photo: courtesy of Todd Burrows, South Stradbroke Island)

They grow to a length of about 1 cm. They are often attended by ants as they exude excess sugar syrup. The syrup is also deposited on the leaves, which then can become mouldy, reducing the light reaching the leaves The mould, the loss of nutrients, and the injection of poisons into the plant all damage infected plants.