"Willow" writes:
Ouch! Thanks for the information John. Do you know if the fungus affects
citrus at all? The lemon's leaves are about a 1m off the ground, but the
leaves of the mandarin are very close.

I'd guess not. I have a lemon whose lower branches sweep down onto the
ground. They seem perfectly healthy. I can't bring myself to prune them
off because these branches fruit well, too. I do have a lot of straw
under the tree, so the leaves rest on that, rather than moist soil: it's
moist because the tree needs a lot of watering, the surface of our sandy
soil drys out quickly in the heat, and citrus are very shallow rooted.
Perhaps you could layer newspapers under your tree, conceal them with a
layer of straw or something, and poke the hose into a couple of holes to
get water to the roots? I have heard conflicting things about using news-
papers around the garden, that they stop rain getting to the roots. But
if rain falls on the newspaper, and doesn't get to the roots, where does
it go to??? I can see that a light sprinkle might not get through, but
once the paper is soaked through, further rainfall must get through.

There could be a drawback to having leafy branches right down to ground
level: reduced air circulation. So anyone living in a humid climate and
having problem with mould might be advised to thin out the branches and
encourage air to circulate under and through the tree. Also, just because
the leaves seem uneffected by contact with the soil, I'm hesitant to
believe that the same would go for any fruit resting on the soil; I'd at
least layer plenty of dry coarse straw for the fruit to rest on.
--
John Savage (for email, replace "ks" with "k" and delete "n")