A sharp stream of water knocks the Aphids off the plant, it does not crush or otherwise harm them, and they are too stupid to find their way back to where they came from and they then starve to death.
Some Aphids do have wings, at one stage of their develpment but not all Aphids have wings and even those that do only have them for a short time.
Perhaps this from the University of California will be of some help.

Here is a link that might be useful: About Aphids

and they are too stupid to find their way back to where they came from and they then starve to death.

==>>> well i often curse mother nature..

but here.. lets give her a gold start.. lol .. 2 thumbs up

ken

ps: so i dont need my 2 hundred thousand foot pound pressure water pump for this??? ... lol ..

I've done this to elephant ears, a Gardenia shrub that had 'em BAD, and various potted plants. The force needed to knock aphids off of EE's with a stream from the hose is often cosmetically damaging to the leaves but they continue to function even if they are somewhat damaged. Ants may bring them back eventually.

As I'm sure you know, Ken, aphids like to get on the bottom of leaves and in the crotches of nodes. Knocking them off with water not something you can do with a shower setting, you need a pretty strong stream. So for this reason, I haven't found it to be practical on a large area but works well on plants that I micro-manage. Just knocking a significant amount of aphids off of something like a shrub seems to help a lot, allow the plant to recover faster than the few you missed are sucking it dry.

For house plants I use a squirt bottle set on a direct stream setting. This seems to kill them in some way because they do not crawl or walk around after they get knocked off. I sit down and hold each leaf, check both sides, so I would notice if the ones I knocked off were crawling around. I used to be concerned with turning the plants sideways so the critters wouldn't fall into the pot but I'm a lot less anal about it since they don't seem to come back unless/until the ants bring them. Aphids don't seem to show up unaided/unattended.

Seldom is the pressure of water from the garden hose (45 to 60 psi) necessary to knock Aphids off any plant. A bottle with a sprayer attachment is usually most ample.
Water with the pressure of your supply system can, and will, damage plants.

indoors.. couldnt you just add a bit of dish soap ... to aid the kill ..???

ken

Dish soap is not for plants. This wrong idea needs to be corrected. There are substances in dish soap that are not necessary for insecticidal purposes and can be harmful to plants. If you want to use insecticidal soap, that's what you should get.

I wasn't talking about a garden hose with a naked end above, was assuming there's some kind of adjustable nozzle.

According to Colorado State University...

"Hosing plants can lethally injure aphids and very few surviving aphids that are knocked to the ground can successfully find their way back onto their host plant."

So yes, the water itself can and does kill them due to the fact they are such soft bodied critters.

tj

Today the term "dish soap" can be used by the manufacturers of detergents, synthetic stuff often made from the residue of the petroleum distillation process. Most all of the "soaps" we buy today are really detergents since few are still made by reacting animal fats with lye.

hey junkie.. so they arent that stupid.. lol ... never underestimate ma nature ...

of course.. its all about population control ...

the few that find their way back.. wont do significant damage.. until they replicate a couple billion new kids i suppose ...

ken

With pot plants you can hold the whole thing sideways under the tap/faucet(with one hand over the potting medium so it doesn't wash out) and clean it using your fingers to sloosh the foliage. No need for any additions to the water.