On 24 July, 14:54, Dan Griffin Dan.Griffin.
wrote:
Hello Everyone. *This is my first visit to this site and so I may be
posting in the wrong area. *If this is the case, whoops. *Please, I need
some help.

According to the book, 'The House Plant Expert' by Dr DG Hessayon I have
a Dieffenbachia picta Camilla and I have been following the care
instructions contained within. *I have had them (both plant and book)
for about four months and the plant has been growing well until the last
few days. *All of a sudden the lower leaves are yellowing. *They are not
dry to the touch. *Many of the leaves have about a millimetre of 'brown'
and yellow on the tips.

It sits in a well-lit spot out of direct sunlight. *It is never too cold
nor too warm. *I water it every week and a couple of months ago I began
to feed it every three or four weeks (after repotting it on the day of
purchase). *It is in a 10" terracotta pot and currently stands at 10"
high. *As of yesterday I hadn't watered it for a few days.

Last night I dug into the soil at the side of the pot - down to about
three inches - to check if it was waterlogged. *It was very dry and so I
gave it about a half-pint of water. *The leaves are continuing to yellow
rather quickly. *Does anyone know if this plant can be saved? *Am I
doing something horrendously wrong?

Many thanks for your help

--
Dan Griffin
Sounds like the Ph of your soil may be wrong for camillas.
Camillas like an acid soil, have you planted it in an acid pet &have
you been giving it the sequestering stuff? They are unable to gather
nutrients unless the soil is acid.