Corn leaf aphid

Definition

A cosmopolitan aphid species (Rhopalosiphum maidis, family Aphididae) that is the most economically damaging pest of maize (Zea mays) and a significant pest of sorghum, rice, and other cultivated and wild monocots. Adults and nymphs feed in dense colonies within the whorl and on developing leaves, reducing yield through direct sap removal, honeydew secretion promoting sooty mold, and transmission of maize dwarf mosaic virus and other plant pathogens. Populations thrive in warm, dry conditions and are particularly problematic in tropical and subtropical agricultural systems.

Etymology

Common name derived from its primary host plant (maize/corn) and typical feeding location on leaves; scientific name Rhopalosiphum from Greek rhopalon (club) + siphon (tube), referring to the siphunculi, and maidis from Latinized maize (Zea mays).

Example

In the U.S. Corn Belt, heavy infestations of corn leaf aphid during the tasseling stage can reduce grain yields by 15–50% and may require insecticide intervention when economic thresholds exceed 100 aphids per plant.

Synonyms

• Corn aphid
• Rhopalosiphum maidis

Related Terms

• aphid
• Siphunculus
• Honeydew
• vector
• Maize dwarf mosaic virus
• economic threshold
• Integrated Pest Management

Usage Notes

Distinguished from other maize-feeding aphids by its blue-green coloration, dark legs and cornicles, and preference for feeding deep within the whorl of pre-tassel plants. The name "corn aphid" is sometimes used interchangeably, though this can cause confusion with other cereal aphids; "corn leaf aphid" is the preferred common name in entomological literature. Not to be confused with the bird cherry-oat aphid (Rhopalosiphum padi), which also colonizes maize but is smaller and more yellow-green.