Brown scale are sap sucking insects often found on woody plants.
Brown scale are convex, oval, dark brown 'shells', 3-6mm diameter/long, they are most likely found on the woody stems of plants.
To Get Rid of Scale Insects:
Control Ants and the Sap Sucking Insects they 'Farm' in Trees, Shrubs and Ornamantals
There are many species of scale insect in the family Coccoidea. In New Zealand common pest species include: