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Winter Bronzing Bug (Thaumasticoris sp.)

by Andrew Scales | May 21, 2010
Winter Bronzing Bug (Thaumasticoris sp.)


Are your Gum trees turning red-yellow or appear to be dying off?

If so, maybe they are being affected by the sap sucking, Winter Bronzing Bug………………

 Host range

The family Thaumastocoris has had a devastating impact on many Eucalypt species in the Sydney metropolitan area. The host range of this bug has increased from two eucalypt species, Eucalyptus scoparia and Eucalyptus nicholii, to other common eucalypts throughout Sydney’s urban forest.

The pest

The symptom of infestation is so widespread it has a common name “winter bronzing” due to the red-yellowing of the leaves within the cooler months followed by leaf drop. Severely infested trees are usually removed unless early detection and treatment is implemented.

Adult Thaumastocoris bugs are 2mm long and pale brown in colour, with a distinctive ‘X’ on the upper body.  The bugs feed by inserting their sharp, tube-like mouthparts into the plant stem and sucking out the sap. The plants lose water and nutrients, becoming pale and defoliating.


Preventative and curative control is possible with tree injection methods used by Naturally Trees. The products are designed by tree care professionals and university researchers specifically for managing and controlling the insect pests threatening our natural and urban forests.

Injectable tree insecticide is the only trunk injectable insecticide available for use in Australia and is the most environmental and cost effective ways to achieve insect control in trees. 

What are the risks?

Many of the pesticides that were once used in the landscape were quite dangerous to us, our trees and to the environment however the good news is that there is now a very safe and effective product on the market.  Direct injection of the product into the tree presents a very low risk to applicators, the general public and non-target organisms; eliminates the water requirements associated with other conventional application techniques and provides greater flexibility in terms of application in difficult sites.

The tree injection methods can be used in various tree species in gardens, parks, forests, picnic grounds, streetscapes and other areas where protection of trees is warranted.



Winter bronzing damage of a Scoparia gum in Sydney


Winter bronzing bug

Close up of a Thaumasticoris bug