Rooney said
The experience you had pruning and having to remove white faced hornet nest was interesting! Thanks for the extra context regarding pests and deterrence. If this hornet thing is a real solution to larvae apple damage then my guess would be so would paper wasps. The latter are fairly easy to manage safely than hornets. But what's the trick (if any) what makes them attractive to trees?

Possibly queen paper wasps in a screen cell is one idea. It's the way honeybees are sold and moved around from place to pace commercially. I had a bee beard around my hand once with honeybees as a teenager. The farmer allowed me to move bees from raspberry so pickers could harvest the rows.

I have always had paper wasp nests and also codling moths.  There is probably some predation going on but I don't think there is a lot.  The hornets seem to be on a mission when foraging.  i.e. I see them fly up and down every branch.  The paper wasps seem to just be wandering around.

When I encounter the hornets away from the nest, they do not seem aggressive.  The problem is I do not know where they may have a nest.  If I get too close they will defend it.

I did find one apple yesterday with codling moth damage.  But it is definitely way below normal for me.

I also have mono wasps (mason bee parasite).  Does anyone know if they also parasitize codling moth?