Have you ever seen anything similar?

[Lory]

my ponderosa lemons are 3 years old and look quite healthy in their pots.
They already started to bear fruits and this made me very happy 





During the last times more mature laves started to show a weird yellowing path





This really puzzled me since i've never seen such a kind of "inverted chlorosis" 

Examining the lower side of the leaves with a magnifying lens i found nothing strange.
What could it be??

[brian]

Check here maybe: http://edis.ifas.ufl.edu/ch142

Could be...  " With yellow vein chlorosis, the midribs and lateral veins turn yellow while the rest of the leaf remains a normal green color (Fig. 2). This chlorosis is frequently attributed to girdling of individual branches or the tree trunk. It may also occur with the onset of cooler weather in the fall and winter due to reduced nitrogen uptake by the plant from the soil. "

You said this is happening on old leaves only, though?  If so they might just be old and will turn yellow and fall off eventually.  This is normal... oldest leaves will fall off after some time, not sure how long.  Maybe 6mo to a year?

[Lory]

Thanks for the very interesting link.
I started to think it might be a nitrogen deficiency.
I haven't fertilized my plants for a very long time due to the extremely hot and prolonged dry season.

[DimplesLee]

Hi Lory - where did you buy your Ponderosa? I'm looking for a more reliable seller (citrus collector or nursery) within the Philippines. I have a couple of Ponderosas who have been quite runty from the outset and I have taken to grafting scions onto local dayap in an effort to "save" clones but I would rather yank out the parent plants if I can find a source of healthier/better plants. The original batch I bought a couple of years ago
show symptoms of gummosis and they no amount of mollycoddling seems to be doing them any good.

[Lory]

Hello!
Funny to say but my 3 ponderosa lemons come all from a little cutting donated by some russian friends a couple of years ago.
They have an old though little potted plant living in their livingroom.
At beginning,  i was not really so interested in that little branch, i remember i just removed all the leaves but one and i literally just inserted it  in a little pot with some soil and, As it often happens, it startet to grow fast and vigorously.
From that first plant i made another 2 cuttings and now i've a total of 3 all of them fruiting