and brown tips
HAVE two problems. My lemon tree has soot-like build up on the leaves
and seems to be lacking the usual number of flowers for this time
of year. Also the new leaves on my hydrangea are curved and deformed
and some have brown marks on the ends. Any ideas?
sample you sent shows that your lemon tree is infested with scale,
the excretions of which encourage the black sooty mould growth on
the leaves. The easiest way to solve the scale problem is to spray
the whole tree thoroughly with an insecticidal oil such as Conqueror,
Clear White Oil or the canola-based Eco-oil. Make sure to get the
spray on as much of the foliage as practicable, particularly the
undersides of the leaves where many of the scales are sheltering.
Avoid spraying in hot, sunny weather or you run risk of burning
the foliage - early morning on a cloudy day is ideal. Once you get
rid of most the scale the sooty mould will shrivel up and drop off.
Don't worry if you don't
get rid of all the scale, as most lemon trees produce quite good
crops even with a moderate population of scale on them. And give
the tree a good feed with citrus fertiliser to encourage new growth
and better flowering.
The hydrangea sample
was not in very good condition, but I suspect the distorted growth
and brown tips may have been caused by some adverse environmental
condition such as a particularly cold biting wind, a drying wind
or perhaps a light frost which has damaged the new growth. If that's
the case then the plant should quickly recover and subsequent new
growth should be fine.
Gardener, Issue 186, 2005, Page 33
Reproduced with permission from the former Weekend Gardener magazine. The views expressed here are not necessarily those of the RNZIH.