I've got an old and maltreated container grapefruit from seed that I’ve had for, oh about 15 years now. I planted it from a ruby red seed back when I was a kid. Anyway it's still pretty small, I imagine in no small part to my horrible treatment of it.

Until recently it was in just ordinary soil that had become horribly compacted over the years, got regularly over watered and I hadn't really made sure it got enough light. When I recently became interested in citrus growing I realized just how badly I'd treated it and took steps to help it out (re-potted into potting mix, started fertilizing, and put a light on it when it was indoors for the winter).

After I repotted it the leaves started yellowing, and the new growth was stunted. I originally attributed this to root damage during the transplant. However, about at the same time I found out about Tristeza virus and I'm starting to get worried. My grapefruit is:
1) stunted (15 years old and barely 3' high)
2) Has moderate to severe dieback (during the winter, better lighting seems to help)
3) Has become chlorotic (however until I put it into a new medium it was fine)
Which, except for stem pitting, is more or less all the symptoms of Tristeza.

I'm probably just worrying about nothing, as mentioned above the tree has a pretty good reason for all of its problems. Also, I’ve never been in any area that had any citrus growing in it, so I can't figure anywhere it could have contacted a disease.





Oh and some notes, in picture one you can see the variety of ways the leaves are yellowing. The nice green leaves on the left are from a different plant the stuff on the bottom of the leaf is water, I'd been watering the lawn just before the post. And yes, I know that my lawn need mowing.

In picture two you can see the tiny (but properly green) new leaves. There's a bunch of bean leaves in the way; a nearby bean plant has gotten tangled up in the grapefruit. I imagine it's going to make it a lot of fun when I need to take the grapefruit back in.

It looks malnourished and also sunburned. Did you move this out into full sun from some other location ?

Most strains of tristeza do not have much effect on seedling trees; rather, they affect trees grafted to a susceptible rootstock. There is a form in California, known as "seedling yellows," which can cause decline of a seedling, but I'd think the probability of your tree having acquired that strain to be exceedingly low.

Lazz is correct, the leaves are certainly burnt, however the type of damage shown, (burnt leaf tips and margins), looks to be damage resulting form high soluble salts in the root zone. Evidently, the root zone of this container tree has not been flushed out in a very long time, and apparently each watering has not been sufficient enough so that 20 percent of the irrigation water drains out the bottom of the container. The root zone needs to be flushed out with clean clear water in the amount of 4 times the volume of the container. As bad as this tree is, it could even require an additional flushing a week later. Further, the tree look to be very deficient in iron, perhaps due to pH. The symptoms of iron deficiency in citrus are: NEW leaves with green veins with NO border areas around the vein itself, on otherwise yellow leaf. - Millet (1,250-)