The idea with the double fungicide treatment (before cutting, wait a few days, then spray the cut stumps) as opposed to fungicide treatment after cutting was to reduce the number of live spores in the environment, having been disturbed and become airborne from the cutting. It was suggested to me by a plant pathologist that a single treatment after cutting may be sufficient but it would depend on the fungicide also. The cut stumps would get better fungicide coverage. I don't think it has ever been investigated scientifically which might be better. It would also depend on the fungicides used. Since a soil drench with azoxystrobin (Heritage) was effective for a prolonged period of time, I wonder if that would be a viable alternative.
Whether cutting back (without spraying) as you described would work would likely depend on how long it takes before new growth emerges that could encounter spores that are still alive on the cut stumps.
