So... you had pests, overdid the pest treatment, and now your plant is dying as a result? Is that right?
You say "bud rot" in the title, but never mention any mold. What are your symptoms?
Did you do anything different this time than with the previous, successful grows? Or was it just the aphids that sent things in the wrong direction?
As always, some good photos would be a big help.
Besides growing the right strain, I think many hours a day of really intense light helps there.I've never really been able to get dense flowers no matter what I try. Â¯\_(ツ)_/Â¯