New Question about refreshing Cedar Siding

My house has cedar siding. A few years ago, I hired a professional to power wash and re-stain the house (& garage).
I told him it was cedar, but he thought it was pine because of knots or similar.
Anyway, that same year or the next I had insect problems which I discovered when the woodpeckers started poking holes.
Is it possible that the power-washing destroyed the natural insect repellent character? Is there any way to restore it?
Fortunately, the siding is vertical batten board (not sure of spelling) so only a few bits would need to be replaced.
The house is looking dirty again and before doing anything I would like advice on how to clean while preserving cedar properties.

Rex\'s Mom

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