Lemon Trees

Question

Half of my lemon tree has a black mouldy substance on the fruit, what is the cause ans how do I eradicate it?

Answer 1

This could be sooty mold, which can affect both the leaves and the fruit surface. It follows an infestation with aphids or other insects, so controlling the insects is the best way to prevent its appearance. Here is more information:

https://www.gardeningknowhow.com/plant-problems/disease/how-to-get-rid-of-sooty-mold.htm
http://ipm.ucanr.edu/PMG/PESTNOTES/pn74108.html