Root aphid

Symptoms
The foliage turns yellow and practically no new growth is produced. Root aphids attack many garden plants, including aster, Braille, calendula, primrose, and sweet pea, as well as corn and strawberries.

Spot them
Root aphids generally have short legs and short antennae, and, thus, are especially adapted for life in the soil. Where large numbers of these insects are present, they suck out so much sap from the roots that the plants do not receive sufficient nourishment. These little aphids are often attended by ants. The ants not only look after the overwintering aphid eggs, but, in the spring and summer, sometimes actually carry the lice through the soil from one host plant to another. In fact, if a plant, especially an annual, looks sickly and ants are found on the ground nearby, it might be well to hunt for root aphids.