I have just noticed these tinny little black bugs, about 1mm diameter in size.
They are on the very top ticks of the branches of a healthy mandarin tree.
Fruit and Citrus • Pests
It looks like your tree is infested with aphids. We recommend treating them with Yates Nature's Way Citrus & Ornamental Spray. Please click here for more information:
https://www.yates.com.au/product/garden-pest-control/yates-natures-way-citrus-ornamental-spray
yates
Answered: 19 Oct, 2020