I have been growing a few orange trees from seed for the past year. Most of them are growing fine, but a few months ago one of them began developing patches of orange-brown bark/scarring tissue (?) at all the branch points that looks different to the young bark at the base of the plant. The main branch hasn't grown since and the few new leaves that have tried to grow are a very pale yellow-green and misformed. Does anyone know what's causing this / is it a genetic thing?