That happened when my neighbor sprayed roundup on my plant looked just like that before it died
But it was the whole plant I am a noob tho so I am just sharing I doubt this is the case here
It’s looking like a bad case of leaf septoria, please, follow these links instructions…
In hope it’s gone a help you…, good luck…
That’s what I thought it was . You would think after all the years of growing this would of happened at least once not after 30 years of growing!
Same thing here in CT,USA. We have had a hazy hot and humid 3 months. The blight took over one plant on the lower limbs. I used organic copper spray.You really can’t stop it. I cut all the infected leaves, then sprayed and haven’t seen it in 4 weeks. Knock on wood.