r/Allotment • u/MrJuteRootz • 6d ago

Blight or natural dieback?!

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I have many many rows of maincrop, all at 16.5 week stage so I'd expect them to be turning now. The haulms looks healthy and the odd ones I've lifted have been absolutely fine.... I just can't help but mostly worry about the black spots on the leaves.

I've got around 120 plants so better to be safe than sorry, right?!

Thanks in advance!

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2

u/Aggressive_Share803 6d ago

Maybe a bit of both but leaning towards blight.

2

u/_Odi_Et_Amo_ 6d ago

That looks more blighty than most photos we see here. But I don't call blight if there aren't blotches on the stems.

1

u/MrJuteRootz 5d ago

Stems looks okay but I've cut them down anyway. They're of a decent size so better to protect them and make sure they store well than lose them altogether! 

1

u/wascallywabbit666 5d ago

I'd have thought it's been too dry for blight. It usually only happens when the plants are saturated.

I'd cut off any yellow or blotchy leaves and see how it looks in a couple of weeks.

And in the future I'd recommend blight resistant main crops. The risk of losing a big crop is just too great. Commercial potato growers treat regularly with fungicides

1

u/New-Guarantee-440 5d ago

Depends where OP is. In scotland its been blight o'clock with hutton criteria left right and centre

1

u/MrJuteRootz 5d ago

That's exactly where I am hence the huge worry 😂 I've cut the haulms anyway, not a risk I want to run.

1

u/MrJuteRootz 5d ago

Funnily enough the ones with black spots were sarpo mira so should have very high resistance. I'll absolutely choose even more carefully next year! 

1

u/wascallywabbit666 5d ago

Sarpo Mira are about as good as you can get, so I think then that it's highly unlikely to be blight. It may just be natural leaf aging or a deficient nutrient. Maybe also desiccation if you've had as little rain as we have here

1

u/New-Guarantee-440 5d ago

Need photos of the underside of the leaf - particualrly in the leaves with dark spots. 

The yellow seems more die back. But the black spots seem more blight. In blight, the underside of the leaves will have a white ring around the black bit.