Bitumen –an oil ingedient in asphalt- is organic and by that
is the lichen given nutrition.
Lichen creates very strong hold in the asphalt surface and even gets nutrition from damp and dirt that has been gathered in the asphalt. The growth therefore starts quickly and develops quite quick.
As long as the spores is in the surface, the lichen will recur constantly. Lichen is the most difficult affection to treat and prevent. The lichen must be sterilized and the surface must be disinfected for the affections to stop.