What is attacking my Viburnum hedge in my Canberra garden?
A silvery/brown effect has been more prevalent in recent years especially on Viburnum hedges and especially on Viburnum tinus.
Due to some mild Winters and plenty of rain, conditions have been good for insect populations.
The silvery/brown effect is caused by sap sucking insects such as greenhouse thrips and sometimes the two-spotted mite.
They feed on the undersurface of the leaf resulting in a silvery/brown damage on the top side of the leaf.
Control option 1 - Keep the plant happy and healthy by fertilising in Spring and Autumn and light pruning in Spring and early Autumn.
This will keep the plant growing actively and producing new fresh growth to replace/cover the older affected leaves
Control option 2 - Repeat control option 1 but add a low toxicity spray (eg. Eco Oil or Pest Oli/Pyrethrum etc) used in November and December and January. Use these sprays as directed but try to get the spray to contact the insects on the back sides of the leaf as much as is possible.