Infection on Avocado tree?

[reena chengappa]

Hi all,

THis is an Avocado tree in my house in Bangalore.

Does anyone know what those white rounds things on the tree trunk are? And how does one treat this?

Thanks,

Reena

[Mahadeswara]

These are  lichens: composite, symbiotic organisms formed by the association of algae or cyanobacteria and a filamentous fungus.They make interesting pollution indicators, as they won’t grow in polluted air. If lichens start to grow on your trees, that’s good news: a sign that the air is fairly pure! You’ll also see lichens on rocks and sometimes on the bare ground. And while ghostly gray and muddy green are their main colors, they can come in all sorts of shades, even bright oranges, yellows, yes, even pink!

In no way are tree lichens harmful to the bark on which they grow. They are strictly epiphytes, that is, organisms attached to the outside of the bark. They are not parasites (which, by definition, harm their host) and seek nothing from the tree other than a support on which to grow.