Root Aphids

Identification

"Root Aphid" is a very broad term that describes an unknown number of species of aphids that can attack crop roots. They are most commonly seen outdoors, where they feed on leaves of plants and overwinter either as a dormant egg or as a colony feeding on stored sugars/starches in plant roots. Indoors they are common pests due to the concentration of sugars, amino acids, and nutrients in the roots. Aphid eggs are sought after by some species of ants, who will nurture a colony of aphids to feed on their sugar and nutrient rich excrement. A common misunderstanding is the referencing of Root Aphids to phylloxera, which is another family of insects that are very similar to aphids but lacks the telltale "tailpipes" and "honeydew" discharge that distinguishes aphids.

The CHA recommends reviewing the IPM management tools presented by the University of Connecticut Department of Plant Science and Landscape Architecture.  Their research has concluded that:  "Root aphids resemble root mealybugs because they are covered with white wax. However, they are smaller than root mealybugs and have reduced ring like cornicles which are located on the end of their abdomen." (L. Pundt,  2011)

The research from the University of Maryland Cooperative Extension describes certain a genus responsible: "Root aphids in the genus Phemigus are being found with increasing frequency feeding on the root systems of herbaceous perennials. The first thing growers will notice is the white wax that looks like snow-flocking covering the root system.  Root aphids tend to build up populations at the edge of root-balls. Female aphids give live birth to nymphs, and a clustering of aphids builds up on concentrated areas of the root system. Small populations are not a problem; however, when populations become high, the plants are reduced in vigor, and customers will definitely see the white wax." (S. Gill, 2001) university of Connecticut department of plant science

Life Cycle

Root aphids are surprisingly adaptable and their lifecycle can vary tremendously. They reproduce asexually during the growing season. Eggs over-winter in soil or, in warm seasons, are attached to leaves and stems above the root line where they hatch and fall to the ground. The aphid bores into the root, creating scars that leave plants vulnerable to mildew and disease. As infestations increase, “crawlers” will move up the stem to feed. Once a plant is nearly destroyed, some root aphids will develop wings that enable them to seek new plants to attack.

Recommended controls for Root Aphids

Each control will have its own set of parameters that will be best suited for individual environments.  Certain controls may only be available for commercial application.

  Commercial farmers are required to reference their own state laws to ascertain if the recommended controls fall within compliance of their states regulatory guidelines.

Beneficial Insects

Biological Controls

Botanical Controls

CHEMICAL CONTROLS

MECHANICAL AND PHYSICAL CONTROLS

Selected References

Managing Aphids in the Greenhouse. University of Connecticut, L. Pundt,  Revised 2011.

University of Maryland Cooperative Extension, S. Gill, 2001

University of Idaho - Extension