Corn root aphid

The corn root aphid (Anoecia corni) is a member of the order Hemiptera and the family Aphididae. It is a migratory pest that demonstrates a complex life cycle, alternating between woody plants and various graminaceous species throughout the growing season.

The primary hosts for this aphid are plants of the genus Cornus (dogwood). During the autumn, sexual females deposit eggs on the bark of these trees, where they overwinter. In the spring, the nymphs hatch and begin to form colonies, often causing leaf curling and distortion on the dogwood foliage.

As summer approaches, winged alate forms emerge and migrate from the dogwood to secondary hosts, which include various grasses and cereal crops such as maize and millet. Upon landing, the aphids migrate downward to inhabit the root zones of these plants, where they feed on sap and establish subterranean colonies.

The damage caused by Anoecia corni is primarily linked to the weakening of the host plant's root system. By draining sap from the roots, the aphids interfere with nutrient and water uptake. This often results in stunted plant growth, chlorosis, and in cases of severe infestation, reduced crop yields and increased vulnerability to environmental stress.

Effective management strategies involve a combination of biological and chemical approaches. Cultural practices, such as the removal of host weeds and proper tillage, are essential. When chemical intervention is required, systemic insecticides are preferred due to their ability to reach the aphid populations residing on the plant roots.