Golden Cypress help

[Tech]

I bought a golden cypress goldcrest half standard from b&q , it had a small brown patch on it , a couple of months later and the brown seems to be getting worse . I did repot it in a larger container with good compost and have been keeping it watered with use plant food , I have also sprayed it for aphids . Any ideas on how to help it please ?

[bullthistle]

Could be it was denied water before you bought it or else the roots are exposed to air. Once it starts very little can be done to contain its spread.