I am a little surprised that immersed Pings die before the aphids
infesting them. Some Pings grow almost as aquatics, naturally
immersed for part of the year, although I can't speak for US Pings.
Aphids are pathetic at holding their breath - if you care to risk
the might of British Law and spray aphids on roses with dilute
washing up liquid, the aphids are dead in a couple of seconds.
Aphids breathe through their skin, and the washing up liquid
contains wetting agents - perhaps aphids are so small that surface
tension enables them to survive immersion in plain water.
Don't spray Pings with dilute washing up liquid as it is strongly
alkaline.
Good Growing, Nigel Hurneyman