Diatomaceous earth is great because it's nontoxic to your garden but deadly to the aphids killing your plants. Aphids feast on plants by piercing the plant and sucking its moisture. In doing so, they actually transmit a virus into the plant which makes it curl and distorts its growth. If left unchecked, aphids can wreak havoc in your garden. While there are various kinds of pesticides, many people look for organic aphid control as a safer treatment option.
A single aphid can produce 80 offspring in a week. They come in a variety of colors such as green, red, brown, black, and yellow. Check your plants a couple times a week as you walk through the garden or do other activities such as watering and weeding. Look for plants that are yellowing, curling, or exhibiting distorted growth. This could be a sign of an aphid infestation.
If a particular plant is covered in aphids, it might be better to just cut it off and dispose of it. This won't completely eliminate the problem, but it can slow it down enough so you can keep ahead of the aphids.