My tree is indeed indoors - unfortunately it can't be kept outdoors at the moment as I live in a flat (with a very narrow windowsill!). I try to have the windows by the tree open whenever I can, but you are probably correct about the lack of air movement. The tree is never in direct sunlight. It is quite warm indoors at the moment (South-East England). I started watering by submerging up to the base of the tree in water, as advised in the bonsai shop, but I now mist the tree instead - I can't see any webs when I do this. I'm afraid I don't know what kind of soil it is - there are lots of small pieces of gravel in the soil. The surface of the soil is convered in small spiky green moss. I feed the tree around once a week with a general fertiliser, again from the bonsai shop (N1.6, P4.3, K5.5, Ca2.3, Mg1.6). The pests really are very small - less than mm, and appear on both sides of the leaf, seeming to congregate around the edges. They seem much keener on younger leaves. Thanks for all your advice so far - any more would be much appreciated. I will try to move the tree to somewhere where it will get as much air as possible. I don't want my first tree to die!