In "The fruit expert by DG Hessayon" he suugests painting all wounds with arbrex. (also to avoid pruning in winter)

What is arbrex (some kind of wood sealant?)?

My local garden centre chap reckons this is an outdated tecnique and current practice is to leave the wounds alone so what ever gets in isnt sealed in.

What does everyone think?

Cheers

Ed