This appears on quite a number of my Japanese maples. It is dry and crumbly. I am thinking some kind of insect fingy but can't find out for sure. Anybody recognise or can identify the thing?
Hi Sam, Nice to see you back here, hope you've been well. And the maples too. ;) Kind of just looks like lichen to me, hard to tell in the without more of a closeup though. If so, harmless. but a bit unsightly. Can be crumbled off with the fingers. cheers, -E
Tree Lichen wouldn't worry to much about it, some of my JM have exactly the same if it gets to big or just annoys you to much just rub it of with your fingers that's what i do. Check the RHS website for more info if needed,or just 'google' tree lichen.
Hi Emery ... I have been fine thanks ... just getting older etc :) Good to hear that it is harmless ... someone says it shows good quality air :) I will google it anyways ....
Looks like lichen to me, too. Does it have a woodsy, moss-like smell when crumbled? And yes, I've been told it's an indicator of good air quality, too.
The only thing is that it can host pest eggs during the winter, that's why bonsai growers usually remove them. I think if the tree is small enough, you should remove them, for insects can propagate diseases that are more harmful than the damages caused by the insects themselves: they usually don't wash their hands when going from one -infected?- tree to another, do they, so to be on the safe side, I'd remove as much of it as possible.
Indeed! Lichens are widely used as environmental indicators or bio-indicators. If air is very badly polluted with sulphur dioxide there may be no lichens present, just green algae may be found. If the air is clean, shrubby, hairy and leafy lichens become abundant. A few lichen species can tolerate quite high levels of pollution and are commonly found on pavements, walls and tree bark in urban areas. The most sensitive lichens are shrubby and leafy while the most tolerant lichens are all crusty in appearance. Since industrialisation many of the shrubby and leafy lichens such as Ramalina, Usnea and Lobaria species have very limited ranges, often being confined to the parts of Britain with the purest air such as northern and western Scotland and Devon and Cornwall. See: http://www.air-quality.org.uk/19.php Best! Andres
The only bonsai I left lichens on because of the colours. Sorry, it's not a maple, and I will remove them in autumn because I love it and I don't want to see it die (Larix x marschlinsii, syn. Larix x eurolepis, "Dunkeld Larch"). It's about 30cm high and in a very shallow pot, but it's very healthy:
