Aphids attack a multitude of plants in all stages of plant growth. They are small, pear shaped and come in a variety of colors. They are recognized by the 2 tubelike structures at the end of their body called cornicles. Aphids feed by using their mouthparts to suck plant juices out of leaves and fruit. They secrete a sticky substance called honeydew that ants love. Sometimes ants farm aphids, moving them around. Generally, natural enemies of aphids keep them in check. However, if you have sprayed an indiscriminate insecticide, the lady beetles, syrphid fly larvae, aphid lions and small wasp parasites known as braconids will also be killed and an aphid population can increase exponentially. A strong stream of water will knock most aphids off the plant and in doing so break off the mouthparts so they can’t eat anymore. For more information on aphids, here is a link from K-State Research and Extension.
https://hnr.k-state.edu/extension/info-center/common-pest-problems/common-pest-problem-new/Aphids.pdf
https://hnr.k-state.edu/extension/info-center/common-pest-problems/common-pest-problem-new/Aphids.pdf