New Leaf Problem

[Tim DH]

Does anyone recognize this problem? Its new to me!

It is affecting all the plants in one bed (6 different cultivars) They are all grafted plants. Other beds not affected. Lower leaves are yellowing. Higher up, the main/primary leaflet of each leaf turns first, mostly from the tip.

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Any ideas/advice gratefully accepted!!

Tim DH

[bower]

Lower leaves yellowing, usually means there's a shortage of N, and perhaps those low leaves are also not getting much light, so the plant withdraws the nutrients from the lower leaf to feed new growth. It may also be damp in the lower canopy, which is ideal for early blight (Alternaria) to invade, especially if the plant is poaching nutrients from those oldest leaves.
The last two pictures could be early blight. Check for a "ring spot" with a darker line around a lighter center - this would be typical and your last pic does look like it.
OTOH the tip yellowing as seen in the first pic, in upper canopy (which in the greenhouse tends to be warmer and dry) is something I see here and which I've been blaming on mites. Some kind of tiny pest which does best in heat and dryness, which always attacks those upper canopy leaf tips here when it gets sunny and warm.
The pic 3 leaf is notably yellowing from the tips - which is not really typical of Alternaria blight, those spots appear at random placements - so I would suspect a combination problem involving tiny pest plus Early Blight.

[MissS]

@Tim DH It looks to me like you have a bit of Early Blight. As Bower has said eventually you will be seeing some type of halo effect around the spots.

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I would suggest removing the affected leaves and then spraying your plants with a fungicide and a week later with copper as a preventative. Keep alternating between the two. Clean up all plant material as the can live in your soil.

[bower]

When leaf tips are affected I often just pinch off the affected tip, instead of taking the whole leaf.
I figure it simulates herbivory and might stimulate plant defenses.
OTOH I'm not skilled with sprays, but they might work much better.