From: Friends of Jerrabomberra Wetlands
I’ve been very concerned to see that most Blakely’s Red Gums in our area appear to be suffering some fairly sudden and severe dieback. Blakely’s Red Gum (Eucalyptus blakelyii) is one of 2 key species in the nationally critically endangered plant community Yellow Box – Red Gum Grassy Woodland.By dieback I am referring to trees that appear sick or dying, without an obvious cause. There are many possible causes of dieback: phyphthophera infection, uncontrolled and sustained insect attack (generally resulting from a lack of small woodland birds), exposure to herbicides, or other stressors such as salinity or prolonged drought. It’s thought that there is generally a combination of stressors that result in dieback that eventually kills trees.A listener to The Gardening Show on local ABC radio this morning raised this issue, and several others chimed in with similar concerns. I was so relieved to hear Graham “Willow” Williams, that cheerful, kind and keen horticulturist, arborist and long-time Canberran, say he reckons it is caused by Autumn Gum Moth caterpillars (Mnesampela privata). He thought this largely because it is so sudden, particularly affecting E. blakelyii, and it’s at this time of year. He says it is probably just a bad year for them (well, a good year for the moths!), and the red gums will generally make a full recovery.
From Geoff Butler of Wamboin
I was wondering whether the infestation on E. blakelyi is not Psyllids (lerp) rather than autumn gum moth as the infestations of psyllids around Wamboin and Murrumbateman are very extensive this year. Look for small translucent “scales” all over the leaves.