well, growing lawn around citrus is usually not good. Clear to bare soil for at least 2 feet past the drip line, 4 feet is better.
also while flowers like nasturtiums are good at repelling pests, they also are not good growing in the near root zone of a citrus tree. Bare soil or mulch. I prefer mulch
Mulch also will do several other things, it will cool the soil, temper the water retention, and slowly feed micro-nutrients that the tree need. That will help with the yellowing.
Lastly, for more than half of the fruit to drop is normal, but there should still be some that remains to maturity. I recomend clear out the other vegetation, such as flowers and lawn, and use a good mulch to nourish the soil.

thanks softmentor - I will try all those things. probably made a similar mistake as I planted a dwarf cara cara right next to the ruby red (only2 years old - no fruiting yet) and it displays same leaf coloring and texture as ruby red. there is evidence of holes and eating on some leaves, but not throughout the tree. would you recommend spraying the ruby red for pests in the future and if so what type of spray?
thanks!