Melbourne gardeners, check your citrus trees! Citrus gall wasp, unknown in southern Victoria until 18 months ago is spreading and gardeners need to be vigilant about controlling it.
A Melbourne gardener recently contacted GardenDrum for help about what is infesting her lemon tree (see photo above), a tree that had been highly productive until this year. The answer is the dreaded citrus gall wasp which causes lumpy stems as the plant reacts to the laying of wasp eggs under the bark.
This debilitating pest can only be controlled if gardeners check their citrus trees, including lemon, grapefruit, orange, lime and cumquat and prune off any galls before the wasps emerge and then fly off to lay eggs in another tree.
Read more details about what to do and when from Kaye at Save Our CitrusĀ on GardenDrum
It is not accurate to say the the gall wasp was unknown in Melbourne until 18 months ago. In 2009 the lemon tree in my suburban Melbourne garden had so much gall wasp I cut off every branch in an attempt to control it. In 2012 the branches had grown back, and the wasp came back as well. A photo I took of one gall that year was later published in Michael Mobb’s book, “Sustainable Food”. I also have a photo I took in 2013 of a dead lemon tree in a Melbourne garden, where every branch is swollen with galls – multiple years worth of them before the tree died.