utdeedee, This technique is called Companion Planting. It's not so much getting rid of pests, but deterring them. And also to attract beneficial insects that eat the pests we do not want. You can also look up Intercropping , here is a good place to start: Intercropping Principles and Production Practices. There is also an entire forum here at GW devoted to the topic: GardenWeb Companion Plants Forum Here is a link that might be useful: Lengthy List of Companion Plants

Sevin, Carbaryl, is a very broad spectrum poison that will kill beneficial insects as well as the target insect, and has been so overused over time that many insects are developing immunities to that product and so it is no longer effective against them in some places. If the sharp spray of water, which does need to be repeated often and frequently, does not work (keep in mind that many people do not understand the life cycle of an aphid and will claim that sharp spray of water will not work because they know not) maybe, possibly you might need to move up the toxicity ladder to Neem products or pyrethrins which also are very broad spectrum poisons that will kill any insect, good, bad, or indifferent, they contact. Aphids will start to produce live young almost as soon as they are born, live, themselves so by the time you see any Aphids on your plants you could easily have 5, or more generations of Aphids there. Spraying those you see off your plants leaves a vacancy for the next generation to move in. Those you knock off are not smart enough to know where they came from and do not climb back up, they will however starve to death since they do not know where their food source is. So you knock some Aphids off today and tomorrow there are more that need to be knocked off, not the same ones you already did. Knock those off, keeping in mind the buggers have been producing more young that will appear in a bit for you to knock off. The best control for Aphids is however to be sure the soil your plants are growing in is a good and healthy soil that will produce strong and healthy plants that are better able to withstand insect pests. Plants that have a lot of insect pests on them are telling you there is a problem that needs to be addressed, and that most often involves the soil.

Hello Diana....I have around 50 potted Angel Trumpets in a spare room of my house, last week I noticed aphids on about half of them...I searched on Googel for a cure, many different opinions on how to cure these little things....I used 1 tspn of dawn dish liquid in a qt bottle sprayer, I tryed this, but it didn't seem to effect them...So I added just a tiny bit more dawn, sprayed again and it killed all of them....There was no effect on the leaves....You may want to wait on other opinions here before you try this, I don't know what effect this will have on banana leaves....Merry Xmas, SNC299

To expand what ken said, the aphids secretes a sweet substance that the ants feed on, so as Ken says ...get rid of the aphids and you will get rid of the ants by spraying them with water or using insecticidal soap..... As for the "critter in the spit".....it is a spittle bug that is sucking the plant juices from your plant and is protected by the frothy foam......best way to rid them is to wash them off with water.... Here is a link that might be useful: spittle bug