hi everyone , i recently bought a monkey puzzle tree from the botanical gardens edinburgh , it's about a foot high , when i got it home i noticed it had some white powdery substace over the leaves , which is getting worse :-( . can anyone tell me what this is and how to get rid off it . any help would be much appreciated , bill
That tree looks diseased, I'm sorry to say. The white material does not look like it's a precipitate, and the black spots definitely look fungal. Unfortunately I can not give you any more information than that as I'm not very well versed in what diseases affect species of Araucaria. Also, you might know this already but be aware that "monkey puzzle" is a common name which generally refers to the species that's the more cold hardy and can be planted outside in parts of the UK, but the species you have is sometimes mistakenly referred to as a "monkey puzzle" as well, but will not be hardy below 0 degrees Celsius. THe more cold hardy one is native to Chile, the one you have is Araucaria Bidwillii and is native to Queensland. It can easily be grown as a houseplant as well, though.
May be scale insects of some sort. Try washing it off with a pressure hose; if the problem re-appears, then try a systemic insecticide.
would like to see a photo more of the whole plant please to tell whether it is a bunya pine or monkey puzzle and yes that looks nasty and diseased and in need of a fungicide spray.cheers graeme wild wood arboretum.