I have several Sungold tomato plants that have recently developed dark brown mottling on the lower, older leaves, and from what I have read on the web, I reckon this is most likely Early Blight. Like the fool I am , I neglected to clear the remnants of last years tomoto plants from the garden until about February, so I am guessing that's where it came from, but is there anything I can do about it? Or are these plants destined for the bonfire?

Please give me good news!