From the economics point of view the cereals make up the great majority of the production seeing that they cover over 9 million hectares and are grown on one out of two of all farms. Their role in crop rotation is especially significant in that these farms are very large-scale operations.   

Three species of aphids regularly occur on wheat, barley and maize:

• Rhopalosiphum padi is particularly abundant on maize at the end of summer and beginning of autumn, and on early-sown winter cereals (beginning of October)
• Metopolophium dirhodum and Sitobion avenae in their active stage mainly in spring, on barley but especially on wheat

See Aphid damage on Poaceae

In the Aphid key folder you will find simplified keys based on photos or morphological criteria to help with identification of species.

These aphids are followed by a whole procession of parasitoids, which in turn are divided into frequent and occasional species. In the Parasitoid key folder you will find a simplified key based on morpohological criteria  (wing venation) backed with photos.

In a similar way the parasitoids are followed by a procession of hyperparasitoids as listed here. In the Hyperparasitoid key folder a simplified key is presented based on morphological criteria and backed with photos.