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How to Manage Pests

Identification: Key to Aphids Commonly Found in Small Grains, Corn, and Sorghum in California

Note: This key includes only the aphid species that are most commonly found in small grains (wheat, rye, and barley), corn, and sorghum in California. If you are unable to identify an aphid using this key, contact your local Cooperative Extension farm advisor for assistance.

Numerous aphid species attack small grains, corn, and sorghum in California throughout the growing season.

Most of the aphids found in small grains, corn, and sorghum and included in this key are Russian wheat aphid (Diuraphis noxia (Mordvilko)), bird cherry-oat aphid (Rhopalosiphum padi (L.)), English grain aphid (Sitobion avenae (F.)), greenbug (Schizaphis graminum (Rondani), corn leaf aphid (R. maidis (Fitch)), yellow sugarcane aphid (Sipha flava (Forbes)) and rose-grain aphid (Metopolophium dirhodum (Walker)).

Proper aphid management requires accurate identification, as economic thresholds are developed for individual species.

Use this key to identify winged (alate) and wingless (apterous) adult aphids. While aphids appear to be very simple insects, they are really very complex, both in their biology and their morphology. As with other insects, external morphological features are used to identify individuals to the species level.

Drawing of typical aphid

This drawing of a typical aphid shows a number of morphological features important in identification.

  1. Look at an aphid through a 10x hand lens to see the important characters that distinguish it from others included in this key.
  2. On each page of the key, click on the box that best matches the character of the aphid you’re trying to identify.

Begin the Key

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