Canterbury
June
Q.
Hi, my lemon tree has black mould on the leaves where the sun doesn't get to, and it is also in direct line of outside heat pump unit. What do you suggest? Thanks Tui
Sandra
A.
Hi Sandra
That is sooty mould, it is caused by sucking insects such as scale or aphids. If you look closely you will see bumps on the stem or leaves, or scale insects in the new foliage on the underside of the leaves. Spraying the tree with milk will remove the sooty mould, but you need to control the insects. We suggest asking your local garden centre or DIY store for a suitable spray for sucking insects.
Thanks, Tui Team
Post a comment
How can I get rid of black mould on my lemon tree leaves? Comments
I see our good orange tree in the Nelson/Tasman area struggling with black soot. I have used Neem oil a couple of times. Do I need to use milk only or can it be watered down somewhat? I very much hope this method will keep it alive. Many thanks, kind Regards Luregn
Luregn
Hi Luregn, the sooty mould is there because you have sap sucking insects such as scale, aphids, or mealy bug on your tree that excrete honey dew as they feed. You may find ants on the tree too, they also feed on the honey dew. Sooty mould is spread by wind, it lives on the honey dew and while it doesn't kill the tree, looks unsightly and reduces the vigour of the tree. If you control the insects the sooty mould will eventually disappear, and can be cleaned up by spraying the tree with undiluted milk or better still, use a horticultural spraying oil that will also control the insects, repeat applications may be required. Eventually the sooty mould will wash off with rain.
Lianne