My tree is very vigorous too, it is the most vigorous pluot that I have (a little bit more vigorous than DD, which is quite vigorous too). Brown Rot is very well under control with my spray regimen, the only pluot that had rot last year was DD and only in the fruits with split pits, which cannot be controlled by spraying. I spray fungicide (Infuse or Bonide Fruit Tree & Plant Guard)/insecticide with NuFilm every 2-3 weeks starting late April (when Plum Curculio starts showing up) till 3-4 weeks before harvest. With that, BR is really insignificant across the board (not only pluots). I also bag my fruits when they start coloring up, to protect from birds, but it may be helping a little with disease and insects.
@fruitnut I have a different theory for FS’s lack of production. I think it is lack of enough sun/heat in the few weeks following pollination/fruit set. Last year I saw a lot of tiny wild bees working my FS (more than any other pluot)! This year I was away during bloom so can’t tell about pollinators, however, initially I had a very good fruit set, but then 99% of the fruitlets dropped over the following few weeks, which I think was because of cold weather and/or lack of sun, both conditions necessary for light-dependent and non-light dependent biochemical reactions used to make sugars (the source of energy and structural material) by the tree. I know one can argue that the dropped fruitlets were not pollinated, yet, this would not account for lack of fruit set despite hand pollination (experienced by @scottfsmith, me and others). To support my theory, people who reported good fruit set with FS are mainly in CA and @Jwsemo in MO (Flavor Supreme pluots - #10 by Jwsemo), both places have better sun/warmth than the north east at pollination/fruit-set time. Having said that, FS may poorly attract some types (or the more common types) of bees, which could be the cause of poor set in your greenhouse for instance, where you have a single type of bees.