Aphids are herbivores. They suck plant juices out of the leaves, stems, or roots of plants. The juices they drink often have much more sugar than protein. Aphids have to drink so much sugary juice to get enough protein that they excrete a lot of the sugar.

Do aphids kill plants?

Although aphids seldom kill a mature plant, the damage they do and unsightly honeydew they generate sometimes warrant control. ... On mature trees, such as in citrus orchards, aphids and the honeydew they produce can provide a valuable food source for beneficial insects.

Do aphids eat vegetable plants?

These soft-bodied insects damage plants by piercing the leaves and stems, then sucking out sap. Aphids on vegetables are green, yellow, red or brown, and pear-shaped. ... Although aphid feeding may not kill a vegetable plant, they often spread viral and bacterial diseases, which can wipe out an entire crop.