A couple of years back I planted a fever tree outside our gate. The tree never really took off. It didn’t die or look sickly, it just never seemed to grow. I put it down to the fact that the soil I had planted it in was this terrible, sandy, red earth and decided to give it some time to come right.
However, earlier this year, I noticed a black moss growing on the trunk and branches of the tree and thought I better do something about it. First I Googled black moss but didn’t come up with anything useful. Then I went to take a closer look at the tree and noticed hundreds of small, black ants moving up and down the tree trunk. Could the ‘black moss’ actually be the ants footprints, I wondered?
After a bit more Googling, I found something that surprised me. Both the ants and black moss were indicator species, pointing to the real culprit, aphids. I went back to inspect the tree for a third time and lo and behold, there in the leaves, were hundreds of tiny aphids.
So, in pulling all the pieces of the puzzle together, I worked out that the ants were protecting and ‘milking’ the aphids for their carbohydrate rich excrement, called honeydew. This was also coating the trunk and branches of the tree, providing a perfect environment for the black moss to grow.
Solution, kill the ants and let the aphids natural predators control the population.
Result, the fever tree has suddenly sprung to life.