Hello, bb! First of all, you need to remember that any healthy plant can tolerate some aphids. You can probably keep them in check with frequent sprays of water. Because they multiply so rapidly, you'll need to tend to this chore regularly.

In most situations, ants aren't a problem. However, some ant species can make an aphid problem worse by defending them against the other critters that may feed on or control aphids.

And we also do not want fire ants in our gardens or anywhere that they may cross paths with people or pets. Not only because their stings are painful and can be dangerous, but fire ants are also capable of doing damage to our plants.

Aphids can be a problem in gardens but the simplest ways to control them start with your soil and a balanced nutrient level. Many entomologists, people that study insect behavior, will tell you that Aphids are more attracted to plants that are growing in soils with excess Nitrogen levels.
Understanding something about Aphids can help control them.

Here is a link that might be useful: About Aphids

The above seems to think that all aphids behave the same with some 4000 different species across 10 different families, that is making a huge jump in reality.

Aphids congregate to different plants for different reasons - lush new growth that may be caused by excessive nitrogen is only one. And not even a significant one at that. Lupine aphids show up on old, spent flower stalks, ditto hellebore aphids. And fertilizing or the lack of fertilizing has no bearing - they just paper. To make the assumption that just focusing on the quality of your soil will have a major impact in controlling any aphids is just not so.

Sprout aphids (actually cabbage aphids) ARE hard to control if they become numerous, primarily because they hide away inside the emerging sprouts or cabbage heads.
Neem oil, insecticidal soap or even all-season horticultural sprays can be effective if you are early and persistent but I'd go with a strong water spray first.

The aphids generally don't ruin the plant although they can make it look rather funky. And no worries if you don't get them all........just a little extra protein with your veggies :-)

Aah Gardengal, numerous garden writers such as Lee Reich, Ann Lovejoy, Rebecca Cole, Elliot Coleman, and many more that I cannot even remember would disagree with you because they have been telling people for some years now that a good healthy soil that grows strong and healthy plants will have fewer insect problems then plants growing in just any soil.
The entomologists that contributed to the article I attached above write in that article that Aphids are more likely on plants growing in soils with too much Nitrogen, as you would learn if you read the article, or one of the many others available from university research people.
Soil is not just an anchor to keep plants from floating off into space, soil contributes much to a plants nutritional needs if that soil is properly prepared, and that means much more then simply throwing some NPK on the soil occasionally.

Yes, its true that excess nitrogen can result in excess aphids. However, it is a vast oversimplification to suggest that you can control aphids, much less all insect pests, by improving your soil. In my experience with cabbage aphids, if you get the nitrogen level so low that the aphids do poorly, then the plants are underfed and grow poorly as well. The tricky thing about cabbage aphids in brussels sprouts is that once they get inside the "sprout", they are very difficult to get rid of with anything. To grow this crop, you need to watch for cabbage aphids and start some treatment program, even spraying water, as soon as you find any.

Aphids are also attracted to the succulent newest growth, which is more nitrogen rich than the older counterparts....naturally. Even in times of nitrogen deprivation, tissue testing will reveal that nitrogen is mobile within the plant, ensuring continued new growth.

Pest insects have an extremely strong drive to feed on plants.....some of them are genetically marked to seek out specific kinds of plants. We all know that if we plant a vegetable garden, there will be a wide assortment of phytophagous insects having a party on our plants.

What kimmsr SHOULD be emphasizing is that plants grown under ideal horticultural standards are likely to suffer fewer consequences and to recover more quickly than those in poor condition in the first place.

YES, there is ample and easily accessed research data to show that some pests AND diseases infest and infect plants in poor health. I learned about that in my university studies over 30 years ago as well during 30 years of hands on and eyes on professional experience.

One shouldn't ignore genetics OR culture in our desire to help others with their garden woes. Kimmsr, one cannot control aphids 'simply ' by starting with the soil. It's much more complex than that.

Thank you Dorie and Bob - that was exactly point I was trying to make. Oversimplification or attributing aphids to only a single cause is misleading and not the slightest bit helpful.

aphids when washed away with water will simply walk or fly right back onto the plants and can even be spread to other parts of the same plant or to other plants. some thousands of years of dealing with rain I think that have found a way to over come water. aphids feed by sucking liquid from the plants, they can breed either by direct mating or by cloning them selves so even a single female aphid can turn into hundreds before you know it. the best insecticide is a systemic killer as it makes the whole plant toxic but these can not be used of food crops for the same reasons. so the next best thing is natural killers like ladybug and lacewings, nematodes, or soaps. the ants you see at the aphids are farming and taking care of the aphids. the aphids give off a honeydew liquid that the ants feed on, so the ants will protect, help, and even move them to better plants and move the aphids out of the rain. ladybugs are cheep and eat aphids with a passion both the adult and baby ladybugs eat aphids and as long as there is food they will stay where they are needed. a great place I found to find natural control and other garden items is http://eartheasy.com/

Scorp....the chances of aphids walking back to a host plant is next to nil. We aren't talking about a gentle downpour but a rather sharp, directed spray.

Most think that water sprays (and squishing) should be the first course of action against aphids, rather than buying ladybugs and shipping them in.

Populations of wild, native ladybugs are being decimated and 'farm raised' insects are usually the Asian ladybugs.

A far better solution is to foster a native and natural population of a variety of predatory and parasitic invertebrates.