Might be a plant disease, or it might be the result of a change in growing conditions that have produced plant chlorosis. What might have changed with this plant? Soil pH? Watering? Is it pot bound?

http://extension.illinois.edu/focus/index.cfm?problem=chlorosis

lets see a pic of the whole. is this a giant plant in an old tiny pot ...

pot media does wear out ... how long in that pot???

ken

What plant is it? (The name, please.)

Growing indoors or out?

And where are you?

Perhaps a virus?

Was it a sudden onset or gradual? Almost looks like water damage caused from really cold water. Didn't y'all recently have a bunch of rain, some with hail? Would make for some really cold rainwater. Is it spread evenly throughout or more so to outer/top leaves? How's the new growth?