Lemon tree deficiency

Hello again

This is my originally espaliered dwarf Eureka that I’m now going to grow more as a hedge. It has many baby lemon buds as mentioned in my previous email. But this new growth looks like it has a couple of issues.

The rest of the tree is quite healthy. I was thinking of spraying it with the pictures Yates product. What are your thoughts? Would I spray all over or only in the affected area? It has been fed with the fertilizer we bought from you according to your Fact sheet plus some light topping of cow manure compost.

Thank you in advance.
Heather